Comparison of Two Fixed Beta-Blocker-Pilocarpine Combinations

Purpose

To compare the efficacy and safety of a newly developed ophthalmic solution containing carteolol 2% and pilocarpine (2% (CBS341A) with a timolol 0.5% and pilocarpine 2% fixed combination.

Patients and Methods.

A randomized, double-masked, multicenter study was conducted in 209 patients with primary open-angle glaucoma or ocular hypertension, whose intraocular pressure (IOP) was higher than 21 mm Hg on bet-blocker twice a day alone. The test medications were administered twice daily for 4 months. IOP was measured at 9 and 11 a.m. at the beginning of the study (with beta-blocker alone) and after one and four months of treatment. Adverse effects were recorded.

Results

Both combinations caused a similar, statistically significant decrease in IOP. At four months, in the CBS341A group a 2.4 mm Hg (9%) reduction in IOP was achieved at 9 a.m. and 4.1 mm Hg (17.3%) at 11 a.m. compared with respectively 3 mm Hg (11%) and 4.5 mm Hg (19.5%) in the timolol-pilocarpine group. No statistical difference was observed between the two groups in safety and efficacy.

Conclusions

The carteolol-pilocarpine combination appears as safe and as effective as the timolol-pilocarpine combination in the medical treatment of primary open-angle glaucoma or ocular hypertension.

Corneal Epithelial Deficiency Induced by the Use of β-Blocker Eye Drops

Two studies were conducted to check the effects of β-blocker eye drops, 2% carteolol (Mikelan®) and 0.5% timolol (Timoptol®), on regeneration of corneal epithelium in rabbit eyes. For the short-term study, epithelial deficiency was artificially induced in the cornea of albino rabbits. One of the β-blocker eye drops or 0.005% benzalkonium chloride was applied in the right eye and physiological saline solution was applied to the left eye four times a day, and wound healing rate was calculated. Two weeks later, images of the surface epithelium were analyzed by scanning electron microscopy and proliferative capacity was studied, using proliferating cell nuclear antigen as a marker. The long-term study was conducted similarly except that the eye drops were applied twice a day and epithelial deficiency was re-induced every two weeks.

In the short-term study, epithelial wound healing rate was slowed in β-blocker groups. Significant differences were detected between the Mikelan® and Timoptol® groups, and the benzalkonium and physiological saline groups. The β-blocker groups had severe epithelial cell desquamation, as well as detachment. In the long-term study, the Mikelan® group had significantly delayed wound healing at first induction, the benzalkonium group showed delay up to the third induction and the Timoptol® group up to the fifth induction. These studies indicate that β-blocker eye drops delay corneal epithelial wound healing and supported the concept that corneal epithelial deficiency occurs clinically after the long-term administration of β-blocker eye drops.

Color Doppler Imaging Study in Patients with Primary Open-Angle Glaucoma Treated with Timolol 0.5% and Carteolol 2%

Purpose

To evaluate with color Doppler imaging (CDI), in patients with primary open-angle glaucoma (PDAG), the possible influence on ocular hemodynamics of a beta-blocking agent with intrinsic sympathomimetic acitivity (carteolol 2%) compared to a beta-blocker agent without this activity.

Methods

A study was carried out on 20 patients, with bilateral POaG, intraocular pressure (IOP) ≤ 20 mmHg, all treated twice a day with timolol maleate 0.5% ophthalmic solution. The visual field was evaluated (Octopus 2000 perimeter, G1 program) examining the mean sensitivity (MS) and the mean defect (MD). CDI was carried out to evaluate the resistance index of the internal carotid artery (ICA), the ophthalmic artery (OA), the central retinal artery (CRA), and the short posterior ciliary arteries (SPCA). After these examinations, the therapy was changed to carteolol 2% twice a day. After six months of treatment the examinations were repeated. The data were analysed statistically using Student's t test.

Results

The mean intraocular pressure during treatment with timolol 0.5% was 16.7 ± 1.67 mmHg and 16.33 ± 1.72 mmHg after treatment with carteolol 2%, the difference not being significant (p=0.494). After six months of treatment with carteolol 2% the MS increased significantly from 22.4 ± 2.5 dB to 24.1 ± 1.8 dB (p=0.018), and the mean defect (MD) fell from 5.3 ± 0.8 dB to 4.7 ± 0.6 dB (p=0.011). There was no significant difference in the resistance index of the CA, the OA and the CRA with the two treatments, whereas the resistance index of the SPCA dropped significantly, from 0.80 ± 0.05 to 0.77 ± 0.02 (p = 0.017).

Conclusions

CDI did not show significant differences in the resistance indexes of the internal CA, the OA, and the CRA after treatment with carteolol 2% but the resistance index of the SPCA was significantly reduced. Carteolol 2% induced significant changes in the perimetric indexes examined, with an increase in MS and a decrease in MD. These findings suggest that the intrinsic sympathomimetic activity of carteolol may reduce peripheral vascular resistance of the SCA, thus improving perfusion of the optic nerve head, with a protective effect on visual function.

Randomized, Controlled, Phase 3 Trials of Carteolol/Latanoprost Fixed Combination in Primary Open-Angle Glaucoma or Ocular Hypertension

PURPOSE

To assess the intraocular pressure (IOP)-lowering effects and safety of a carteolol/latanoprost fixed combination drug (OPC-1085EL) vs latanoprost (Study 1) and carteolol (Study 2) in patients with primary open-angle glaucoma (POAG) or ocular hypertension (OH).

DESIGN

Multicenter, randomized, evaluator-masked (Study 1)/double-masked (Study 2), parallel-group studies.

METHODS

Setting: Twenty-eight clinical sites (Study 1) and 19 clinical sites (Study 2) in Japan.

STUDY POPULATION

Outpatients with bilateral POAG or OH whose predose IOP was 18 to <35 mm Hg in the study eye after 4 weeks' treatment with latanoprost (Study 1) or carteolol (Study 2) (defined as baseline).

INTERVENTION

In Study 1, 237 patients applied OPC-1085EL (n = 118) or latanoprost (n = 119) for 8 weeks. In Study 2, 193 patients applied OPC-1085EL (n = 78), carteolol (n = 78), or carteolol/latanoprost concomitant therapy (n = 37) for 8 weeks.

MAIN OUTCOME MEASURE

Adjusted mean IOP reduction at predose from baseline to week 8.

RESULTS

In Study 1, the adjusted mean IOP reductions (95% confidence interval [CI]) were 2.9 (2.5-3.3) mm Hg and 1.6 (1.2-2.0) mm Hg in the OPC-1085EL and latanoprost groups, respectively (P < .0001). In Study 2, the adjusted mean IOP reductions (95% CI) were 3.5 (3.1-3.9) mm Hg and 1.6 (1.2-2.0) mm Hg in the OPC-1085EL and carteolol groups, respectively (P < .0001). All adverse drug reactions of OPC-1085EL observed in both studies were mild in severity and only 1 patient in each study discontinued because of an adverse drug reaction.

CONCLUSIONS

OPC-1085EL is superior to latanoprost or carteolol alone in terms of lowering IOP, and was well tolerated.

[Effect of 0.004% travoprost and 2% carteolol on intraocular pressure in patients with ocular hypertension after laser peripheral iridotomy or trabeculectomy in primary angle-closure glaucoma]

OBJECTIVE

To compare the intraocular pressure (IOP) lowering effect of 0.004% travoprost and 2% carteolol in patients with ocular hypertension (OHT) after laser peripheral iridotomy (LPI) or trabeculectomy in primary angle-closure glaucoma (PACG).

METHODS

Clinical case control trial. 52 consecutive PACG patients (52 eyes) with IOP > 21 mm Hg (1 mm Hg = 0.133 kPa) after LPI or trabeculectomy were enrolled. 24 patients received topical application of 0.004% travoprost (once daily) and 28 received 2% carteolol (twice daily). IOP lowering effect of travoprost and carteolol before and after treatment was measured by Goldmann tonometer and compared using t-test. The relationship of IOP lowering effect and the degree of angle open was performed by gonioscope and analyzed using Spearman rank correlation.

RESULTS

Compared with pre-treatment, the IOP was significantly reduced in 24 patients (24 eyes) in 0.004% travoprost group [pre-treatment: (24.67 ± 3.08) mm Hg, post-treatment: (18.58 ± 2.71) mm Hg; t = 6.600, P < 0.05], while significantly reduced in 28 patients (28 eyes) received 2% carteolol [pre-treatment: (23.57 ± 1.60) mm Hg, post-treatment: (19.57 ± 1.60) mm Hg; t = 5.130, P < 0.05]. 0.004% travoprost group is more significant in both quantity and percentage of IOP lowering than 2% carteolol (t = 2.533, 2.532; P < 0.05). There was no correlation between the IOP lowering effect and the degree of angle open in both groups (0.004% travoprost r = 0.145, 0.009; P > 0.05; 2% carteolol r = 0.090, 0.183, P > 0.05).

CONCLUSIONS

Both of 0.004% travoprost and 2% carteolol reduce IOP in patients with OHT after LPI or trabeculectomy in PACG. 0.004% travoprost is more effective than 2% carteolol in IOP lowering. However, the decrease of IOP is not acted through the alteration of anterior chamber angle in both study groups.

[Long-acting carteolol hydrochloride 2% ophthalmic solution phase IV study--investigation of the effectiveness, safety and plasma concentration]

PURPOSE

We investigated the effectiveness, safety and plasma concentration of long-acting carteolol hydrochloride 2% ophthalmic solution (LA) as compared with the original carteolol hydrochloride 2% ophthalmic solution(CA).

METHODS

Patients with primary open angle glaucoma and ocular hypertension were randomized to 62 patients of LA group (LA once a day) and 62 patients of CA group (CA twice a day) in this multicenter, open-label trial. The intraocular pressure (IOP), pulse rate, blood pressure and plasma concentration were examined for 8 weeks.

RESULTS

The IOP reduction and reduction rate were not significant at any point between the two groups. Systolic blood pressure decreased significantly in both groups, however, diastolic blood pressure decreased only in the CA group. The plasma concentration of the LA group was significantly lower than that of the CA group.

CONCLUSIONS

The IOP reduction effect of the LA group was the same as the CA group. This study suggests that long-acting treatment with alginic acid can be useful for reducing systemic side effects.

Changes in optic nerve head blood flow induced by the combined therapy of latanoprost and beta blockers

PURPOSE

To assess the effects of combined therapy with latanoprost and beta blockers on optic nerve head (ONH) blood flow in normal-tension glaucoma (NTG) patients.

METHODS

Intraocular pressure (IOP), ONH blood flow (laser speckle flowgraphy) and blood pressure were measured in 15 eyes of 15 NTG patients (41-76 years old) before treatment or after a 1-month washout period. Similar measurements were performed at 2 months after the commencement of treatment with latanoprost and at 3 months after the start of combined therapy of latanoprost with 0.5% timolol or 2% carteolol in a crossover study using the envelope method. Measurement was carried out 2-3 hr after the morning application of eyedrops.

RESULTS

Latanoprost decreased IOP with no significant change in ONH blood flow. Concomitant use of timolol or carteolol further decreased IOP with no significant difference between these two drugs. Only the combined therapy of latanoprost with carteolol significantly (p < 0.01) increased ONH blood flow by approximately 10%, compared to initial levels. There was no significant change in mean blood pressure, ocular perfusion pressure or pulse rate as a result of these therapies.

CONCLUSION

Topical latanoprost-carteolol combined therapy increased ONH blood flow in NTG patients, unlike latanoprost-timolol therapy. Because ocular perfusion pressure was unchanged, direct vasodilative effects were suspected as the mechanism.

Environmentally Responsive Ophthalmic Gel Formulation of Carteolol Hydrochloride

Environmentally responsive gel formulation for ocular controlled delivery of carteolol hydrochloride (HCl) was developed in an attempt to improve ocular bioavailability and hence decrease its systemic absorption and side effects. The viscosity and the ability of the prepared formulations to deliver carteolol HCl in vitro and in vivo were monitored and compared with an aqueous commercial solution. The effect of polymer concentration and drug concentration on the in vitro release of carteolol HCl was examined. Gelrite formulations showed pseudoplastic behavior with thixotropic characteristics and the viscosity of the prepared systems increased as the concentration of the polymer increased. At fixed drug concentrations, as the Gelrite concentration increased, the drug release decreased. At fixed polymer concentrations, as the drug concentration increased the release of drug increased. Gelrite formulation (0.4% w/w) containing 1% drug showed significantly improved bioavailability compared with the commercial aqueous solution (Arteoptic 1%). The developed in situ gel formulation showed potential for use as delivery systems with superior ocular bioavailability of carteolol HCl.

[Ocular hypotensive effect of 1% carteolol long-acting eye drops--a double-masked, randomized phase III study in ocular hypertension or primary open-angle glaucoma patients comparing long-acting carteolol eye drops vs. current product]

PURPOSE

To compare the ocular hypotensive activity and safety profile of long-acting 1% carteolol hydrochloride eye drops (long-acting formulation) to those of 1% carteolol hydrochloride eye drops(currently prescribed drug) for reduction of intraocular pressure.

SUBJECTS AND METHODS

Patients with primary open-angle glaucoma or ocular hypertension (146 cases) were assigned randomly to the long-acting drug group (74 cases) and the currently-prescribed drug group (72 cases). Long-acting eye drops were instilled once a day in the morning (along with one drop of placebo at night), and currently-prescribed eye drops were instilled twice a day in the morning and at night. Eye drops were administered for 8 weeks. Intraocular pressure was monitored at 2, 4, and 8 weeks after the initiation of drug instillation for evaluation of equivalence.

RESULTS

Intraocular pressure was significantly reduced during the entire follow-up period in both groups. In the long-acting drug group, the reduction of intraocular pressure was--3.5 +/- 0.2,--4.3 +/- 0.2 and--4.6 +/- 0.3 mmHg at 2, 4, and 8 weeks, respectively (paired t test). In the currently-prescribed drug group, the reduction of intraocular pressure was--4.1 +/- 0.2,--4.4 +/- 0.3 and--4.6 +/- 0.2 mmHg at 2, 4, and 8 weeks(paired t test). The safety profile was similar in both groups, and the tolerance for the long-acting eye drops was as good as for the currently-prescribed eye drops.

CONCLUSION

Because the efficacy of both drugs was equivalent, with an identical safety profile, the long-acting eye drops seem to be an efficacious formulation for clinical use in Japanese glaucoma patients.

[The deleterious effect of certain surface active agents on the ocular surface]

Most ocular solutions enter the eye through the corneal epithelial barrier. In order to pass through this barrier, these hydrosoluble drugs require to be associated with a detergent agent to increase topical efficiency. Although these agents have a preservative action, it was recently demonstrated that, after short or long term use, toxic side effects on the ocular surface will occur.

Measurement of inflammatory cytokines by multicytokine assay in tears of patients with glaucoma topically treated with chronic drugs

AIM

To investigate the ocular surface inflammatory response to chronic topical treatments in patients with glaucoma by measuring the cytokine level in tears using multiplex bead analysis.

METHODS

Tear samples were collected from 21 patients with glaucoma and 12 healthy volunteers. Tears were analysed for the presence of 17 cytokines: interleukin (IL)1beta, IL2, IL4, IL5, IL6, IL7, IL8, IL10, IL12, IL13, IL17, granulocyte-colony stimulating factor, granulocyte-macrophage stimulating factor, interferon (INF)gamma, monocyte chemotactic protein (MCP)1, macrophage inflammatory protein 1beta and tumour necrosis factor (TNF)alpha. The cytokines in each sample of tears were measured using multiplex bead analysis with microspheres as solid support for immunoassays.

RESULTS

In the tears of treated patients, proinflammatory cytokines (IL1beta, IL6, IL12, TNFalpha) were significantly increased compared with controls. T helper (Th)1 (INFgamma, IL2) and Th2 (IL5, IL10, IL4) type cytokines were also significantly higher (p<0.05); however, the most marked increase was observed with Th1 cytokines. The expression of chemokine IL8 and MCP1 was also increased in the treated group.

CONCLUSION

This study shows that pro-inflammatory cytokine secretion by conjunctival cells is increased in response to topical treatments for glaucoma. The characterisation of cytokines in tears was previously limited by the small volume attainable, a limitation that has been overcome by multiplex analysis.

Comparison of the Additive Effects of Nipradilol and Carteolol to Latanoprost in Open-Angle Glaucoma

PURPOSE

To compare the effects of nipradilol and carteolol on intraocular pressure (IOP) when added to latanoprost treatment for glaucoma patients.

METHODS

Fifty patients with primary open-angle glaucoma were treated with latanoprost 0.005% once daily for 3 months. Then they were assigned to one of two groups randomly. One group received nipradilol 0.25% twice daily (nipradilol preceding group; n = 25), and the other carteolol hydrochloride 2% twice daily (carteolol preceding group; n = 25), for 3 months in addition to latanoprost. Then, nipradilol and carteolol were switched, and the subjects were treated for 3 more months. One eye was selected randomly for analysis.

RESULTS

In the nipradilol preceding group, IOP was 21.4 +/- 2.3 mmHg (mean +/- SD) at baseline, and 16.8 +/- 1.9 mmHg at the end of latanoprost monotherapy (P < 0.01). The addition of nipradilol decreased IOP to 15.8 +/- 1.7 mmHg, and the change to carteolol, to 15.3 +/- 2.0 mmHg. In the carteolol preceding group, IOP was 21.2 +/- 2.0 mmHg at baseline, and 17.0 +/- 2.1 mmHg at the end of latanoprost monotherapy (P < 0.01). The addition of carteolol decreased IOP to 15.4 +/- 1.8 mmHg, and the change to nipradilol, to 16.3 +/- 1.9 mmHg. Additional IOP reduction was greater with carteolol than with nipradilol (cross-over analysis of variance; P = 0.0005).

CONCLUSIONS

Both nipradilol and carteolol have additive effects when used in combination with latanoprost. Carteolol, however, may have a more potent effect than nipradilol.

Comparison of carteolol plasmatic levels after repeated instillations of long-acting and regular formulations of carteolol 2% in glaucoma patients

BACKGROUND

A new long-acting (LA) formulation of carteolol 2% instilled once daily has been shown to provide a therapeutic effect similar to that of the regular formulation of carteolol 2% instilled twice daily. This study was designed to test whether the new formulation reduces the systemic delivery of carteolol.

METHODS

In this double-masked, randomised, intra-subject comparative study, 23 patients with bilateral primary open-angle glaucoma or bilateral ocular hypertension received sequentially, according to the randomised order of administration, each of the 2 following treatments: carteolol 2% LA once daily for 2 months and carteolol 2% regular twice daily for 2 months. Treatments were instilled in both eyes throughout the study period. At the end of each period of treatment, blood samples were taken immediately before the last morning instillation (residual time), then 30 min, 1 h, 2 h and 4 h after this instillation in order to measure the carteolol plasma concentrations.

RESULTS

The mean values of maximal plasma concentration (C(max)), residual level and area under the curve obtained following carteolol 2% LA treatment were significantly lower than the values obtained after carteolol 2% regular treatment (mean+/-SD): C(max) (ng/ml): 1.72+/-0.85 versus 3.64+/-3.65; residual level (ng/ml): 0.70+/-0.58 versus 1.80+/-0.84; area under the curve (ng/mlxh): 5.50+/-2.66 versus 10.27+/-5.46. Regarding safety, two drug-related, non-serious adverse events were reported in the LA group: one case of moderate, superficial, punctate keratitis and one case of "bitter taste in the throat." Both treatments appeared to be well tolerated.

CONCLUSIONS

The data from this study showed that the systemic delivery of carteolol is lower for the once-daily LA formulation than for the regular twice-daily formulation. Consequently, long-acting carteolol eye-drops should reduce the risk of beta-blocking systemic side effects.

Ocular Factors Relevant to Anti-Glaucomatous Eyedrop-Related Keratoepitheliopathy

PURPOSE

To evaluate the ocular factors contributing to keratoepitheliopathy in glaucoma patients treated with or without anti-glaucomatous eyedrops, and the influences of each anti-glaucomatous eyedrop to keratoepitheliopathy.

METHODS

The presence and severity of keratoepitheliopathy was investigated in 193 eyes of 110 glaucoma patients. The ocular factors examined were the status of the lipid layer of the tear fluid as assessed by a specular reflection video-recording system, tear volume assessed by Schirmer's test, and tear film stability assessed by tear break-up time. The influences of combined anti-glaucomatous eyedrops and each anti-glaucomatous eyedrops to keratoepitheliopathy were investigated.

RESULTS

The overall occurrence of superficial punctate keratitis was 29.0%. Superficial punctate keratitis was more frequently observed in patients who used more than two anti-glaucomatous eyedrops (35.9%) than in those who used without (19.7%) and one (30.9%). Results of Schirmer's test and break-up time were worse in patients who used combined medication. The occurrence of superficial punctate keratitis in patients who used timolol (46.2%) was significantly more frequent than in those who used carteolol (4.2%). Severity of superficial punctate keratitis and break-up time in patients who used timolol were significantly worse than in those who used carteolol. There were no differences of keratoepitheliopathy and ocular factors between patients who used latanoprost and unoprostone.

CONCLUSION

The usage of multiple anti-glaucomatous eyedrops induces keratoepitheliopathy by reducing the tear volume and the tear film stability. Carteolol may be used more safely for corneal epithelium.

[Efficacy and safety of long-acting carteolol 1% once daily. A double-masked, randomized study]

PURPOSE

Carteolol is a beta-adrenoceptor antagonist with intrinsic sympathomimetic activity. Used topically to reduce intraocular pressure, it is typically applied twice daily. In an effort to provide a once-daily dosing regimen, carteolol was formulated with 1% alginic acid. Sodium alginate is a natural polymer product with bioadhesive properties providing increased corneal contact time and a better carteolol penetration through the cornea. The objective of this study was to evaluate the efficacy and safety of long-acting 1% carteolol alginate solution compared to standard 1% carteolol solution.

METHODS

This was a double-masked, parallel group, multicentre study. Patients with ocular hypertension or open angle glaucoma (n=151) were randomly assigned to receive either 1% carteolol alginate once daily (AM) or standard 1% carteolol solution twice daily for 2 months. The masking was maintained through the use of a placebo in the evening for the alginate group. Entry into the study required unmedicated intraocular pressure (IOP) between 23 mmHg and 32 mmHg at 9 AM and 11 AM. Patients using ocular hypotensive medication were required to undergo a washout. All patients provided written informed consent. Excluded from the study were patients with angle closure, congenital, secondary glaucoma or advanced glaucoma; any intraocular infection or inflammation, ocular trauma, ocular surgery or laser trabeculoplasty within the previous 3 months; contraindications to the use of beta adrenoceptor antagonists; systemic medications likely to modify IOP prescribed or modified during the previous 3 months; ocular steroid use; contact lens wear; and pregnant and lactating women. Patients were evaluated at baseline, 15 and 60 days, with IOP measurements at 9 AM and 11 AM. At day 15 and day 60, IOP was measured just before instillation of medication (9 AM) and 2 hours after (11 AM). Slit lamp examinations were performed at each follow-up examination, together with measurement of heart rate and blood pressure (10 AM) and ocular tolerance after medication (11 AM). The primary efficacy criterion was the decrease in IOP from baseline at day 60 for each measurement at 9 AM and 11 AM. The study eye was the eye with the higher IOP at day 0 or, if equal, the right eye.

RESULTS

Efficacy-of the 151 patients included in the study, 149 were evaluated (two patients were lost to follow-up after day 0): 74 in the alginate group and 75 in the standard group. Both treatment groups were comparable at day 0 except for sex, diastolic blood pressure, and IOP in the fellow eye. At 09.00 hours (presumed trough) on day 60, mean reductions from baseline in intraocular pressure were 6.32+/-2.87 and 5.67+/-3.30 mmHg for the alginate carteolol and standard groups, respectively. At 11.00 hours (presumed peak), mean reductions were 6.70+/-2.81 and 6.55+/-3.35 mmHg, respectively. At each evaluation time, the two unilateral t tests were highly significant (p<0.005), confirming the equivalence of both treatments. Conclusions were not modified taking into account sex and diastolic blood pressure. Safety- Slight decreases in heart rate and blood pressure means were observed in both groups at follow-up visits with no significant difference between groups. Subjective tolerance upon instillation was judged good or very good at day 60 by 100% of alginate patients and by 98.7% of standard patients. Transient discomfort (mainly stinging or burning sensation) was reported by approximately 4% - 6% of patients in each treatment group at each visit. A blurred vision sensation was reported by 2 out of 74 patients of the alginate group. Among the 17 reported adverse events, three were assessed as drug-related: one vertigo, one superficial punctate keratitis in the alginate group and one decrease in blood pressure in the standard group. No serious adverse events were reported.

CONCLUSIONS

The new alginate formulation of long-acting carteolol 1% given once daily is as effective as standard 1% carteolol given twice daily, with no meaningful differences regarding safety. This efficacy wasy was verified at 9 AM (24 hours after the last drop of long-acting carteolol or 12 hours after that of standard carteolol) and at 11 AM (2 hours after the morning drop). The new alginate formulation of long-acting carteolol 1% given once a day is effective and well tolerated by glaucoma patients who require chronic treatment.

Pharmacokinetic and pharmacodynamic differences between ocular and nasal instillation of carteolol on intraocular pressure and heart rate in Japanese men with high CYP2D6 activity

Sublingual administration of carteolol or instillation into one eye reduces intraocular pressure (IOP) in both eyes. This suggests that carteolol absorbed systemically can reduce IOP and that the extra-ophthalmic route (e.g., the nasal route) can be an alternative method of drug administration. The authors compared the differences between ocular and nasal instillation relating to the pharmacokinetic and pharmacodynamic effects of a carteolol-ophthalmic solution on IOP and heart rate (HR) in a randomized, double-blind, crossover, placebo-controlled design in 11 healthyyoung extensive metabolizers for CYP2D6. The tmax, Cmax, and AUC0-t of carteolol (0.8 mg) instilled into the nostril were significantly higher than those into the eye (p < 0.05): tmax (h) = 0.25 (0.17-5.0),1.0 (0.17-5.0) (median value with range in the parenthesis, ocular vs. nasal); Cmax (ng/ml) = 1.33 +/- 1.57, 2.29 +/- 2.09; and AUC0-t (ng x h/ml) = 9.36 +/- 2.04, 21.13 +/- 1.58 (geometric mean +/- SD, ocular vs. nasal). The reduction of IOP after ocular instillation persisted significantly longer than that of nasal instillation (p < 0.05). The HR was significantly reduced after both ocular and nasal instillation (p < 0.05), although there were no significant differences between them. In conclusion, ocular instillation of a carteolol-ophthalmic solution has advantages over nasal instillation in controlling IOP and the potential to decrease adverse reactions due to lower plasma concentrations.

Ocular drug delivery using 20-kHz ultrasound

The cornea is a major pathway for drug delivery to diseased eye structures. We have investigated the application of 1-s bursts of 20-kHz ultrasound, at I(SAPA) of 14 W/cm(2) (I(SATA) of 2 W/cm(2)), for enhancement of corneal permeability to glaucoma drugs of different lipophilicity (atenolol, carteolol, timolol and betaxolol). The permeability of rabbit cornea increased by 2.6 times for atenolol, 2.8 for carteolol, 1.9 for timolol and 4.4 times for betaxolol (all p-values < 0.05), after 60 min of ultrasound (US) exposure in vitro. The differences between the treatment and control experiments were statistically significant after 10 to 30 min of US exposure for all four drugs. US application appeared to produce epithelial disorganization and structural changes in the corneal stroma. Further studies are needed to determine the optimal US parameters for a safe and effective treatment.

Alginic acid effect on carteolol ocular pharmacokinetics in the pigmented rabbit

The effect of alginic acid addition to 1% or 2% carteolol solutions on the ocular penetration of the drug has been evaluated in the pigmented rabbit. During single dose studies, an increase in bioavailability ranging from 40% to 60% was observed in the aqueous humor and in the iris-ciliary body. During repeated dose studies, this increased ocular bioavailability of carteolol in the presence of alginic acid led to an equivalent concentration in the target tissue, although the dosage was only once a day compared with twice a day for the usual carteolol eyedrops. 14C-carteolol distribution studies demonstrated the binding of carteolol in pigmented ocular tissues. Thus, the presence of alginic acid as a new excipient supports a possible decrease in dosage regimen, while retaining sufficient ocular bioavailability to lower intraocular pressure.

Cardiovascular considerations in using topical, oral, and intravenous drugs for the treatment of glaucoma and ocular hypertension: focus on beta-adrenergic blockade

Glaucoma and ocular hypertension are highly prevalent conditions in individuals over the age of 40 and are commonly seen together in patients with cardiovascular disease. Many of the antiglaucoma medications, when systemically absorbed, affect the sympathetic and parasympathetic nervous systems of patients and can cause cardiovascular toxicity. Such adverse effects are frequently associated with the long-term use of potentially toxic agents in elderly people, who are most prone to chronic eye disease. Moreover, patients may not associate their symptoms with the topical eye medications, and consequently may not report adverse drug effects. Drug-drug interactions can also occur when patients are taking medications for both cardiovascular disease and glaucoma. This review focuses on beta-adrenergic blockers as topical antiglaucoma medications and other topical antiglaucoma drugs. The systemic toxicity of these agents is reviewed, along with the possible drug interactions. Brief mention is also made of other antiglaucoma medications used alone and in combination with topical beta-blockers.

Color Doppler imaging of retrobulbar hemodynamics after topical carteolol in normal tension glaucoma

BACKGROUND

Carteolol is a nonselective adrenergic blocking agent. The aim of this study was to evaluate the effect of topical carteolol on retrobulbar hemodynamics in patients with normal tension glaucoma (NTG).

METHODS

Twelve NTG patients received twelve-week topical treatment of 2% carteolol. Color Doppler imaging (CDI) was used to evaluate the hemodynamic effects before and after drug therapy. Measurements were obtained from the central retinal artery (CRA), the lateral posterior ciliary artery (LPCA) and the medial posterior ciliary artery (MPCA). From each vessel, peak systolic velocity (PSV), end-diastolic velocity (EDV), resistance index (RI) and Gosling's pulsatility index (PI) were collected and analyzed.

RESULTS

After topical carteolol treatment for twelve weeks, mean resistance index reduced significantly from 0.83 to 0.74 in the CRA (p = 0.03), from 0.74 to 0.68 in the LPCA (p = 0.09). Moreover, mean pulsatility index of the LPCA decreased from 1.45 to 1.26 (p = 0.08).

CONCLUSIONS

Twelve weeks of 2% carteoiol treatment may decrease the vascular resistance in NTG patients possibly due to the intrinsic sympathomimetic activity (ISA) of carteolol.

Ocular hypotensive efficacy and safety of once daily carteolol alginate

BACKGROUND/AIM

Carteolol is a beta adrenoceptor antagonist used topically to reduce intraocular pressure, typically twice daily. In an effort to provide a once daily dosing regimen, carteolol was formulated with 1% alginic acid. The objective of this study was to evaluate the efficacy and safety of carteolol alginate solution in comparison with standard carteolol solution.

METHODS

This was a double masked, parallel group, multicentre study. Patients with ocular hypertension or open angle glaucoma (n=235) were randomly assigned to receive either carteolol alginate once daily [corrected] or standard carteolol solution, twice daily. The masking was maintained through the use of a vehicle in the evening for the alginate group. Patients were evaluated at baseline, 15, 60, and 120 days.

RESULTS

At 0900 (presumed trough) on day 60, mean reductions in intraocular pressure (IOP) from baseline were 6.09 (SD 2.97) and 6.09 (3.18) mm Hg for the standard carteolol and alginate, respectively. At 1100 (presumed peak), mean reductions were 6.51 (2.53) and 6.47 (2.76) mm Hg, respectively. Results were similar at other times (day 15 and day 120). The most common side effect was transient stinging on instillation of drops, which did not differ significantly between groups. There were no differences of note in other ocular or systemic signs or symptoms.

CONCLUSION

The new alginate formulation of carteolol 2% given once daily was as effective as standard carteolol 2% given twice daily with no meaningful differences regarding safety.

A new long acting ophthalmic formulation of carteolol containing alginic acid

Alginic acid was evaluated as a potential vehicle in ophthalmic solutions for prolonging the therapeutic effect of carteolol. This anionic vehicle was expected to slow down drug elimination by the lacrimal flow, both by undergoing in-situ gel formation and by interacting with the mucus. In vitro studies indicated that carteolol is released slowly from alginic acid formulations, suggesting an ionic interaction. The adhesive behavior of alginic acid solution was better than that of another polymer, hydroxyethylcellulose (HEC). Intraocular pressure (IOP) measurements of rabbit eyes treated with a 1% carteolol formulation with or without alginic acid showed that this polymer significantly extended the duration of the pressure-reducing effect of carteolol to 8 h. The increased ocular bioavailability of 1% carteolol in the presence of alginic acid led to an equivalent concentration in the target tissue although administration was only once a day compared with twice a day for 1% carteolol alone. The overall results of this study indicate that the alginic-acid vehicle is an excellent drug carrier, well tolerated, and could be used for the development of a long-acting ophthalmic formulation of carteolol.

Comparison of the effects of 0.5% timolol maleate, 2% carteolol hydrochloride, and 0.3% metipranolol on intraocular pressure and perimetry findings and evaluation of their ocular and systemic effects

PURPOSE

To compare the effects of 0.5% timolol maleate, 2% carteolol, and 0.3% metipranolol on intraocular pressure (IOP) in 45 patients with primary open-angle glaucoma (POAG) and ocular hypertension. A secondary goal of this study was to evaluate the ocular and systemic side effects of these medications.

METHODS

Measurements of IOP were taken at baseline (pretreatment) and 2, 6, and 12 hours after instillation on treatment days 15, 30, 60, and 90. Mean sensitivity (MS) and mean defect (MD) values of perimetry before and after treatment and the effects of the three beta blockers on serum lipid profiles were determined. Ocular and systemic side effects were recorded.

RESULTS

The most prominent IOP lowering effect was noted with metipranolol at 2 and 6 hours on day 15, and with timolol maleate at 12 hours on day 15 and at all hours of the subsequent days on which measurements were taken. Timolol maleate produced a significant decrease in IOP at 12 hours on day 15 compared with carteolol. There was not a statistically significant difference between the MS and MD values on perimetry before and after treatment for any treatment. There was a statistically significant decrease in levels of total cholesterol and high-density lipoprotein (HDL) cholesterol and a significant increase in triglyceride levels; these changes were observed for all treatments.

CONCLUSION

The effects of the three medications were not statistically different from each other in terms of IOP reduction and visual field changes. Careful monitoring of blood lipid levels is necessary with long-term treatment with beta blockers, because these agents reduced serum levels of HDL and total cholesterol while increasing triglycerides. Such changes in lipid levels could lead to increased incidence of complications, particularly in patients with atherosclerosis or coronary heart disease.

Effect of continuous intravenous infusion of carteolol chloride on tissue blood flow in rabbit optic nerve head

PURPOSE

To investigate the effect of an intravenous infusion of carteolol on tissue blood flow in the optic nerve head (ONH) of rabbits.

METHODS

Rabbits received either a 3-week topical instillation, or a single intravenous injection (10, 20, 30 microg/kg) or a continuous intravenous injection (2.5, 5, 20, 40, 80 microg/kg per hour) of carteolol. The plasma carteolol level was determined by the gas chromatography negative-ion chemical ionization mass spectrometric method. The ONH blood flow was determined by the hydrogen clearance method.

RESULTS

The plasma level of carteolol after a 3-week instillation was 5.55 ng/mL, and a continuous intravenous injection (5 microg/kg per hour) led to approximately the same plasma level. The continuous intravenous infusion of 5 microg/kg per hour of carteolol significantly increased the ONH blood flow compared to the controls from 30 minutes to 2 hours after the beginning of the infusion (n = 10). The mean blood pressure and intraocular pressure (n = 6) were not significantly changed during the continuous intravenous infusion of carteolol.

CONCLUSIONS

These results suggest that the plasma carteolol level in rabbits after long-term instillation can increase the ONH blood flow. We conclude that the increase resulted from a reduction in the vascular resistance in the ONH.

Effects of topical carteolol and timolol on tissue circulation in the iris and choroid

PURPOSE

To evaluate the effects of topical carteolol or timolol on tissue circulation in the iris and posterior choroid.

METHODS

After a topical instillation of 20 microl of 2% carteolol, 0.5% timolol, or physiological saline (for control) into one eye, and physiological saline into the other eye of pentobarbital-anesthetized Dutch pigmented rabbits, normalized blur value; a quantitative index of tissue blood velocity in the iris (NB(iris)) and posterior choroid (NB(cho)) was obtained using the laser-speckle method. Intraocular pressure (IOP), blood pressure and pulse rate were serially monitored for 2 hours after instillation. Using separate groups of rabbits, NB(iris) and IOP were measured before and after 20-day twice-daily unilateral treatment of carteolol or timolol.

RESULTS

After a single instillation of carteolol, NB(iris) was significantly greater only in the treated eyes than control eyes (P = 0.0050, repeated measures two-way ANOVA), while NB(cho) showed no significant change. IOP in the treated eyes significantly reduced (P = 0.0005). Bilateral reductions of tissue vascular resistance in the iris were found after carteolol instillation (P = 0.0183 approximately 0.0322). After timolol instillation, serial changes in NB(iris) and NB(cho) in the treated eyes were significantly different from those in control eyes (P = 0.0129, 0.0031), while there were no significant differences at any of time points (Mann-Whitney test); IOP in both eyes was significantly reduced (P = 0.0096 approximately 0.0005); tissue vascular resistance in the iris and posterior choroid showed no significant changes. After 20-day treatment, NB(iris) in the both eyes of carteolol-treated rabbits significantly increased from the baseline (P = 0.0280, 0.0425, Wilcoxon signed rank test) and NB(iris) in timolol-treated eyes significantly decreased (P = 0.0280).

CONCLUSIONS

A single instillation of topical carteolol significantly increased the iris tissue blood velocity in the treated eye and reduced the tissue vascular resistance in both eyes. Topical timolol tended to decrease tissue blood velocity in the iris and choroid of the treated eye, but showed no significant effects on tissue vascular resistance in the both tissues.

Effects of carteolol and timolol on plasma lipid profiles in older women with ocular hypertension or primary open-angle glaucoma

PURPOSE

To determine the effect on serum lipid levels of carteolol hydrochloride 1.0% or timolol maleate 0.5% given twice a day to women age 60 years and older with primary open-angle glaucoma or ocular hypertension.

METHOD

We included 112 patients in this double-masked, randomized, multicenter trial. Fasting clinical laboratory studies were evaluated at baseline and at 12 weeks. Patients were instructed not to change their dietary, alcohol consumption, or exercise habits during the study.

RESULTS

For the carteolol group, the high-density lipoprotein (HDL) and total cholesterol/high-density lipoprotein (TC/HDL) ratio at baseline of 50.1 +/- 1.5 mg/dl and 4.7 +/- 0.2 changed by the 12-week visit to 51.3 +/- 1.9 mg/dl (P = .25) and 4.6 +/- .02 (P = .47), respectively. For the timolol maleate group, the baseline HDL and TC/HDL ratio of 53.6 +/- 2.2 mg/dl and 4.4 +/- 0.2 changed to 50.2 +/- 1.9 mg/dl (P < .001) and 4.7 +/- 0.2 (P = .001), respectively, at the 12-week visit. Carteolol patients showed no significant change from baseline, whereas the HDL (P < .001) and TC/HDL ratio decreased (P = .001) significantly in the timolol maleate group. There also was a significant difference in the change from baseline at 12 weeks between carteolol and timolol maleate groups for the HDL and TC/HDL ratio (P = .01 and .012, respectively). No differences in TC, low-density lipoprotein (LDL), or triglycerides (TG) or in changes from baseline were observed between groups at 12 weeks (P > .05). At 12 weeks, no differences were observed between carteolol and timolol maleate groups in intraocular pressure or safety (P > .05), except that patients given carteolol demonstrated fewer solicited ocular symptoms (P = .007).

CONCLUSIONS

Carteolol appears to be neutral in its effect on serum lipid levels, whereas timolol maleate adversely affects the HDL and TC/HDL ratio in women age 60 years and older with ocular hypertension or primary open-angle glaucoma.

[The effect of continuous and intravenous application of carteolol chloride on tissue blood flow in the rabbit optic nerve head]

The effect of systemic application of carteolol, which induces almost the same plasma carteolol level as obtained by a long-term instillation on rabbit eyes, on the tissue blood flow in the optic nerve head (ONH) was investigated in rabbits. The plasma carteolol levels in 27 rabbits which received 3-week instillation, intravenous injection (10, 20, 30 micrograms/kg), or continuous intravenous injection (2.5, 5, 20, 40, 80 micrograms/kg/hr) were measured by gas chromatography-negative-ion chemical ionization mass spectrometry. The plasma level with 3-week instillation was determined as 5.55 ng/ml and a continuous intravenous injection (5 micrograms/kg/hr) caused nearly the same plasma level. The intravenous injection of this dose significantly increased the ONH blood flow which was determined by the hydrogen clearance method, compared with controls from 30 minutes to 2 hours after the injection (n = 10). The vascular resistance in ONH was thought to be reduced because mean blood pressure and intraocular pressure (n = 6) were not significantly changed. The results suggest that the plasma carteolol level in rabbits after a long-term instillation can increase ONH blood flow due to a decreased vascular resistance.

Effect of topical carteolol on iridial circulation in pigmented rabbit eyes

The effect of a single instillation of topical carteolol on iridial tissue circulation of pigmented rabbits was studied. The blood flow rate and a quantitative index of tissue blood velocity (NBiris) were measured simultaneously, using the microsphere technique and the laser speckle method, before and 2 hours after the instillation of 20 microliters of 2% carteolol or the vehicle. Consecutive changes of intraocular pressure and NBiris were also studied at 30-minute intervals for 2.5 hours after a single instillation of 2% carteolol in one eye and the vehicle in the contralateral eye. To provide a control, intraocular pressure and NBiris were measured according to the same schedule after the vehicle instillation in both eyes. Two hours after carteolol instillation, iridial blood flow rate and NBiris significantly increased to 127 +/- 8% and 122 +/- 9% (mean +/- SEM, n = 8) of the baseline. Unilateral instillation of carteolol significantly reduced intraocular pressure by about 9 mm Hg in both the carteolol- and vehicle-treated eyes (P < 0.001, analysis of variance); and NBiris was significantly increased by about 20% in both eyes (P < 0.001, analysis of variance), compared with control eyes.

Effect of topical carteolol on tissue circulation in the optic nerve head

The effect of topical 2% carteolol on tissue circulation in the albino rabbit optic nerve head (ONH) was investigated using a laser speckle tissue circulation analyzer. In the first experiment, the normalized blur (NB) value, a quantitative index of tissue blood flow velocity in the ONH, intraocular pressure (IOP), blood pressure (BP), and pulse rate were measured under general anesthesia before as well as 30, 60, 90, and 120 minutes after a 20-microL instillation of carteolol in one eye and the vehicle in the other eye in a masked, randomized manner. In the second experiment, one eye of a rabbit received carteolol twice daily for 20 days and the fellow eye received the vehicle in a masked, randomized manner. The IOP was measured every 5 days, and the NB in the ONH and IOP were measured before treatment and 2 hours after the last instillation on the 20th day. After a single instillation of carteolol, pulse rate showed a maximum reduction of 15%, and IOP in the carteolol-treated eyes showed a maximum decrease of 22%. The NB in the ONH and BP did not show any significant change during the experiment. After 20-day treatment with carteolol, IOP showed a maximum decrease of 25% in the carteolol-treated eyes and 21% in the vehicle-treated eyes. The NB showed a significant increase of 15% (P < 0.01) in the carteolol-treated eyes and 11% (P < 0.01) in the vehicle-treated eyes. It was indicated that long-term topical carteolol increased the blood velocity in the ONH tissue both in the carteolol- and vehicle-treated contralateral eyes in albino rabbits.

Short-term comparative study of topical 2% carteolol with and without benzalkonium chloride in healthy volunteers

AIM

A crossover, randomised double blind study was undertaken in 30 healthy volunteers, in order to compare the tolerance of 2% carteolol with and without preservative in short term use.

METHODS

Complete ophthalmic examinations were performed before and 30, 60, and 180 minutes after instillation of one drop of the solution, and after 3 days of preservative treatment. After a 5 day washout, the same examinations were done with the second drug.

RESULTS

Results showed good general tolerance for both formulations. No significant difference in subjective tolerance, corneal aesthesiometry, punctuate keratitis, Schirmer's test, intraocular pressure (IOP) decrease (about 25% in the two groups at 3 hours, 10% after 3 days of treatment), resting cardiac frequency, or blood pressure was observed. However, break up time was significantly reduced from baseline by preserved carteolol both at 3 hours (10.40 (5.9) seconds to 6.15 (3.9) seconds, p = 0.001) and after 3 days (7.72 (5.5) seconds, p = 0.04). Preservative free carteolol did not significantly change the break up time (baseline 9.08 (5.7) seconds; 3 hours = 7.88 (5.5) seconds, not significant; day 3 = 8.35 (5.8), non-significant).

CONCLUSIONS

These results confirm that carteolol is well tolerated, either with or without preservative. The preservative free group showed better stability of the tear film, without loss of effect on IOP. This difference, although mild in the healthy young subjects in the present study could be much more relevant in those patients treated long term, older patients, and/or those suffering from ocular surface disorders. In such instances, preservative free drugs could be of potential benefit to protect the lacrimal fluid integrity and corneoconjunctival surface.

Effects of topical adrenergic agents on tissue circulation in rabbit and human optic nerve head evaluated with laser speckle tissue circulation analyzer

The effects of topical adrenergic agents on the tissue circulation of the optic nerve head (ONH) were studied in animal and human eyes with use of a laser speckle tissue circulation analyzer. Drugs studied were nipradilol, a beta1-2-blocker with weak alpha-blocking and nitroglycerinlike activities; bunazosin, a selective alpha1-blocker; carteolol, a beta1-2-blocker with intrinsic sympathomimetic activity; and betaxolol, a selective beta1-blocker. In the animal experiment, one eye each of nine albino rabbits received 0.25% nipradilol (N = 9) twice daily for 15 days or 0.01% bunazosin (N = 10) twice daily for 20 days; the fellow eye received the vehicle of each drug in a randomized masked design. Normalized blur (NB) in an area of ONH free of visible surface vessels, a quantitative index of peripheral blood velocity in ONH, was measured under general anesthesia before treatment and 2 hours after the last instillation on the 15th or 20th day. At 15 days, intraocular pressure and NB in the nipradilol-treated eyes decreased by 4.3 mm Hg (P < 0.01) and increased by 15.9% (P < 0.01), respectively, while those in the vehicle-treated eyes showed little change. At 20 days NB in both bunazosin- and vehicle-treated eyes showed little change, while intraocular pressure decreased only in the bunazosin-treated eyes (P < 0.01). In the human volunteer experiment NB was averaged over five pulses (mean NB) in both eyes before and 1.5, 3.0 and 4.5 hours after a 30 microL instillation of the vehicle of carteolol or betaxolol to serve as a control. Intraocular pressure, blood pressure and pulse rate were also measured. One week later a 30 microL drop of 2.0% carteolol (N = 6) or 0.5% betaxolol (N = 10) was instilled in one randomly chosen eye and the vehicle for each drug in the other eye, and those parameters were measured as above in a double-masked manner. In the carteolol experiment, mean NB in both eyes was significantly higher at 3 hours than it was in the control experiment (P < 0.05), while intraocular pressure was significantly lower in both eyes and blood pressure and pulse rate showed little change. In the betaxolol experiment, intraocular pressure at 1.5 hours and blood pressure at 4.5 hours were significantly lower than those in the control experiment (P < 0.05), while mean NB and pulse rate showed little change. In summary, using the laser speckle method we found that topical nipradilol and carteolol increase ONH blood velocity in rabbits and humans, respectively. This finding suggests that some topical beta-blockers used clinically may influence the ONH tissue circulation in patients and that this method may be used in clinical situations to assess the effect of various drugs on ONH circulation.

Effect of topical beta-blockers on tissue blood flow in the human optic nerve head

PURPOSE

To study the effect of topical 0.5% timolol and 2% carteolol on tissue blood flow in the human optic nerve head (ONH).

METHODS

Using a laser speckle tissue blood flow analyzer, normalized blur (NB), a quantitative index of tissue blood velocity, was measured every 0.125 s in the temporal site of the ONH free of visible surface vessels and averaged over 3 cardiac pulses (NBONH). To serve as a baseline, NBONH and intraocular pressure (IOP) in both eyes, blood pressure (BP) and pulse rate (PR) were recorded in healthy volunteers before, 1.5, 3 and 4.5 hrs after a 30L instillation of the vehicle of timolol or carteolol. From the following day and twice daily for 3 weeks, 30L of either 0.5% timolol or 2% carteolol was instilled into one eye and the respective vehicle into the fellow eye in a masked manner. NBONH, IOP, BP and PR were again recorded on the 21st and last experiment day. IOP was also recorded on the 7th and 14th days. Carteolol concentration in the plasma was also recorded after instillation of carteolol on the 21st day.

RESULTS

During the baseline experiments, all the parameters recorded showed no significant change. After topical timolol, IOP was significantly reduced bilaterally with more reduction in the timolol-treated eye. Bilateral NBONH, BP and PR showed little change on the 21st day. After topical carteolol, IOP was significantly reduced bilaterally with more reduction in the carteolol-treated eyes on the 21st day. NBONH in the carteolol- and vehicle-treated eyes was significantly higher on the 21st day than recorded in the same eye in the baseline experiment (P = 0.013 and 0.047), while BP and PR showed little change. The maximum carteolol concentration in plasma at 3 hrs on the 21st day averaged 1294 pg/ml.

CONCLUSIONS

Results indicated that 3-week twice daily topical timolol treatment had no deleterious effect on the ONH tissue blood flow in the human eye, and that 3-week twice daily topical carteolol treatment may increase the tissue blood flow in the human ONH.

Intracerebral penetration of carteolol hydrochloride in rats

To elucidate the penetrability of carteolol, a beta-adrenoceptor antagonist (beta-blocker) into the brain of rats, intracerebral and serum concentrations of the compound were determined in male rats receiving single or repetitive oral administration of carteolol hydrochloride at 30 mg/kg. The time-course of the intracerebral concentration of carteolol following single IV administration of the compound at 10 and 30 mg/kg was also studied in male rats. A high-performance liquid chromatography method was used to determine the intracerebral and serum concentrations. Following single oral dosing, the intracerebral concentration of carteolol reached a maximum of 0.074 microgram/g at 2 h postdosing and declined with a half-life of 3.7 h, and the Cmax and AUC of carteolol in the brain were 12.5% and 19.8% of those in serum. The intracerebral and serum concentrations of carteolol were determined in male rats receiving repetitive oral dosing of the compound once daily for 7 days. The concentration of carteolol in the brain and serum at 1 h postdosing varied within a range of 0.059-0.091 microgram/g and 0.321-0.443 microgram/ml, respectively, throughout the dosing period, showing no changes in the penetrability of the compound into the brain due to repeated dosing. The concentration of carteolol in the brain and serum increased in a dose-dependent manner in rats receiving a single IV administration of the compound. The elimination half-life of carteolol in the serum and brain was 0.6-0.8 h and 1.3-1.7 h, respectively, in rats following single IV dosing of the compound. The half-life in the brain was about twice as long as that in the serum. The brain to serum concentration ratio was 0.306:0.499. From the above results, it was concluded that carteolol is distributed from the circulation to the brain with low penetrability.

Role of central nicotinic and beta-adrenergic receptors in the onset and further development of tail-tremor induced by repeated nicotine administration to rats

The effects of nicotinic and beta-adrenergic receptor antagonists on tail-tremor induced by repeated nicotine administration were investigated in rats. The daily administration of nicotine (0.5 mg/kg/day, s.c.) for 8 days resulted in an augmentation of tail-tremor. However, repeated administration of dimethyl phenyl piperazinium iodide (1 mg/kg/day, s.c.) for 8 days did not cause tail-tremor. Mecamylamine (0.5 mg/kg, i.p), administered before the nicotine injection on each day, abolished the tail-tremor. After discontinuation of the mecamylamine treatment, nicotine injections caused tail-tremor augmentation. Propranolol (20 mg/kg, i.p.), administered before the nicotine on each day, suppressed the appearance of tail-tremor. After the discontinuation of propranolol treatment, the degree of tail-tremor induced by a single injection of nicotine on day 9 was much greater in the propranolol-treated group than in the saline-treated control group. Neither carteolol (20 mg/kg, i.p.) nor metoprolol (20 mg/kg, i.p.) treatment showed such effects. Intraspinal injection of 6-hydroxydopamine markedly enhanced the tail-tremor induced on the first day of nicotine injection. This effect became more intense on subsequent administration of nicotine. The enhanced tail-tremor following 6-hydroxydopamine treatment was abolished by mecamylamine (0.5 and 1 mg/kg, i.p.), and was suppressed by propranolol (5-20 mg/kg, s.c.) in a dose-dependent manner. These results suggest that central nicotinic receptors are essential for the onset and for the further development of tail-tremor induced by the repeated administration of nicotine, and that beta 2-adrenoceptors are associated with the tremor mechanism. Moreover, spinal noradrenergic mechanisms may be involved in the manifestation of this phenomenon.

Cardiovascular effects of topical carteolol hydrochloride and timolol maleate in patients with ocular hypertension and primary open-angle glaucoma. Night Study Group

PURPOSE

To compare the effects of topical timolol maleate 0.5% and carteolol hydrochloride 1% on pulse rate and blood pressure.

METHODS

In a randomized, double-masked, parallel-design, multicenter clinical trial, we compared the effects of timolol and carteolol on pulse rate and blood pressure measured by 24-hour ambulatory blood pressure monitoring in 169 adult patients with either ocular hypertension or primary open-angle glaucoma.

RESULTS

From noon to 8 PM, baseline mean pulse rate of 82 to 83 beats per minute (bpm) had decreased by 4 to 6 bpm in both groups after 4 weeks of therapy with timolol or carteolol. From midnight to 4 AM, the pulse rate in the carteolol group was significantly above baseline (P = .005), while the timolol group was significantly below baseline (P < .001). Four times as many patients became bradycardic (heart rate, < 60 bpm) on timolol (18.4%) as did patients on carteolol (4.5%) from midnight to 4 AM. More than twice as many patients exhibited a resolution of their bradycardia with carteolol (46.7%) as did patients treated with timolol (18.2%) from midnight to 4 AM. Overall cardiovascular adverse effects were reported significantly more frequently in the timolol than the carteolol group (P = .002).

CONCLUSIONS

Timolol causes significantly lower mean heart rate during the nighttime and more nocturnal bradycardia than carteolol does in patients with ocular hypertension and primary open-angle glaucoma. These differences may be because of the intrinsic sympathomimetic activity of carteolol.

[Effect of topical carteolol on visual function in normal-tension glaucoma]

The effects of carteolol hydrochloride on visual function in normal-tension glaucoma (NTG) were investigated. 22eyes of NTG patients were divided into two groups, i.e., (1) a group receiving topical application of 2% carteolol hydrochloride b.i.d. and 2 an unmedicated group. During a 18 month period, intraocular pressure and visual field (measured by Humphrey automated perimetry) were measured every 3 months, and the measurements obtained in the two groups were compared. Analysis of the results revealed a considerable reduction in intraocular pressure in the carteolol group as compared with the control group. The progression of mean deviation tended to be less in the carteolol group, but the intergroup difference in this respect was not statistically significant. However, increase in corrected pattern standard deviation was clearly less pronounced in the carteolol group than in the control group. These results supported the conclusion that carteolol is effective in inhibiting deterioration of the local visual field. This is attributed to increased ocular perfusion due to diminished intraocular pressure, as well as an inhibitory effect upon vasoconstriction in the optic nerve head due to intrinsic sympathomimetic activity, preventing decrease in papillary blood flow and adverse effects upon ocular circulation.

[Effect of non-surgical ocular hypotensive therapy in normal-tension glaucoma]

We investigated the effects of the topical ocular hypotensives with or without half circumference argon laser trabeculoplasty (ALT) on intraocular pressure (IOP) of normal-tension glaucoma (NTG) eyes. Seventy-two NTG patients whose pretreatment mean IOP was > or = 15 mmHg at least in one eye were included and one randomly chosen eye from one patient were used for analysis. They were followed for at least 15 months after commencement of the therapy. The mean pretreatment IOP averaged 17.2 +/- 1.6 mmHg (mean +/- standard deviation, n = 72). All eyes were first treated with topical 2% carteolol. In eyes where IOP reduction was considered unsatisfactory, topical 1% pilocarpine or 0.04% dipivefrine was added. In eyes where IOP reduction was still unsatisfactory even with the two medications, half circumference ALT was performed. Mean IOP reduction was 1.5 mmHg in the eyes treated with topical medications alone and 2.5 mmHg in those treated by topical medications plus ALT. The mean outflow pressure reduction was 16 and 26%, respectively. In 40% of the all eyes, satisfactory IOP reduction was obtained by topical medications with or without additional ALT.

Topical beta-blockade with intrinsic sympathomimetic activity offers no advantage for the respiratory and cardiovascular function of elderly people

Topical therapy with beta-antagonists, such as timolol, may cause unrecognized impairment of respiratory and cardiovascular function in elderly people. Beta-antagonists with intrinsic sympathomimetic or cardioselective properties, such as carteolol or betaxolol, may cause less impairment. In a randomized, double-masked study of glaucoma patients, over 60 years of age, without history of bronchospasm and who were using timolol (0.5%), 60 patients were allocated to betaxolol (0.5%) or carteolol (2%) or continued timolol (0.5%) treatment. Spirometry, pulse and blood pressure were measured on enrollment and after 4 weeks. In the timolol and carteolol groups there were no significant changes in mean spirometric values. Changing to betaxolol improved mean peak flow (PF) by 9.1%, from 310 to 3411/min (p < 0.05) and forced expiratory volume in 1 second (FEV1) by 9.4%, from 1.74 to 1.861 (p < 0.05). Differences in the changes in PF and FEV1 between betaxolol and timolol as well as betaxolol and carteolol groups were statistically significant (p < 0.05). Twenty-one per cent of those allocated to betaxolol showed clinically significant improvement in FEV1. There was no change in pulse or blood pressure when carteolol was substituted for timolol but an increase of 10 beats per minute (p < 0.05) in mean resting pulse in the betaxolol group. Therapy with cardioselective beta-blockade may offer significant advantages in respiratory function for elderly people with glaucoma over non-selective drugs, even if they have sympathomimetic activity.

[Effect of topical carteolol on tissue circulation in rabbit optic nerve head evaluated with the laser speckle microcirculation analyser]

The effect of topical 2% carteolol on the tissue circulation in the albino rabbit optic nerve head (ONH) was studied using a laser speckle microcirculation analyser. In the first experiment, normalized blur (NB), the quantitative index of peripheral blood flow rate in the ONH, intraocular pressure (IOP), blood pressure (BP) and pulse rate (PR) were measured under general anesthesia before, and 30, 60, 90, and 120 minutes after a 20 microliters instillation of carteolol in one eye and a placebo in the other eye in a masked randomized manner. In the second experiment, one eye of another group of rabbits received carteolol twice daily for 20 days and the fellow eye a placebo in a randomized masked manner. The NB in the ONH and the IOP were measured before treatment and 2 hours after the last instillation on the 20th day. After a single instillation of carteolol, PR showed a maximum reduction of 14% and the IOP in the carteolol-treated eyes showed a maximum decrease of 22%, while NB in ONH and BP did not show any significant change during the experiment. After 20-day treatment, IOP showed a maximum decrease of 25% in the carteolol-treated eyes and 17% in the placebo-treated eyes. The NB showed a significant increase of 16% (p < 0.01) in the carteolol-treated eyes and 10% (p < 0.05) in the placebo-treated eyes. This indicates that long-term use of topical carteolol increases peripheral blood flow in ONH tissue in the living rabbit eye.

Ocular distribution of carteolol after single and repeated ocular instillation in pigmented rabbits

To investigate the distribution and elimination of carteolol in pigmented rabbits, 14C-carteolol eye drops were instilled singly and repeatedly. After single ocular instillation, the radioactivity in the iris and ciliary body reached maximum levels at 24 h. The elimination rate of pigmented tissues decreased at a half-life of approximately 15 days. The concentration of radioactivity in pigmented tissues increased markedly by repeating the ocular instillation and reached a maximum after the 80th repeated instillation. The concentration of radioactivity at 1 h after 80th instillation was 63.7 times that in the iris, 61.1 times that in the ciliary body and 17.2 times that in the retina & choroid after single instillation. No accumulation of radioactivity was found in other ocular tissues.

Topical ophthalmic beta-adrenergic blockade for the treatment of glaucoma and ocular hypertension

Since the late 1970s, topical beta-adrenergic blockers have been the drugs of choice in treating ocular hypertension and associated glaucoma. The currently available drugs are timolol, betaxolol, levobunolol, metipranolol, and carteolol. All reduce intraocular pressure by decreasing the production of aqueous humor. Although these drugs are applied locally in the eye, they may enter the general circulation and reach concentrations high enough to cause systemic effects, including alterations in heart rate and rhythm, bronchoconstriction, dyslipidemia, and central nervous system abnormalities. Interactions with other drugs may also occur. Ocular beta- blockers differ in beta 1-selectivity (betaxolol is beta 1-selective, whereas the other drugs are nonselective) and in intrinsic sympathomimetic activity (ISA) or partial agonist properties (only carteolol possesses ISA). These differences give betaxolol and carteolol potential advantages in minimizing certain side effects. The advantage of betaxolol vis-à-vis systemic side effects is more clearly established than that of carteolol. Further systematic study is needed to determine what advantages, if any, are conferred by the presence of ISA.

Ambulatory blood pressure and heart rate during once-daily, randomized, crossover administration of carteolol and atenolol

This study evaluated the effect of beta-adrenoceptor blocking agents (beta-blockers) with or without intrinsic sympathomimetic activity on the 24-hour blood pressure profile of 15 untreated patients with essential hypertension. After a 4-week run-in period, subjects were randomly assigned to an 8-week treatment period of once-daily carteolol (15 mg/d) or atenolol (50 mg/d). The groups were crossed over at week 8. Office blood pressure and heart rate were recorded every 2 weeks and 24-hour ambulatory blood pressure monitoring was performed immediately preceding and at the conclusion of each period. Both drugs significantly reduced (P < 0.01) office blood pressure and heart rate throughout the two treatment periods. The 24-hour ambulatory blood pressure monitoring at 0.5- and 1-hour intervals revealed that systolic blood pressure in 2 of 8 sleeping hours and diastolic blood pressure in 4 of 8 sleeping hours were significantly higher (P < 0.05) after carteolol treatment than after atenolol treatment. The average values for both daytime and nighttime blood pressures, however, were significantly lower at the end of both periods. Although atenolol lowered heart rate throughout the 24-hour period, there was a smaller reduction in heart rate with carteolol than with atenolol during daytime (-5.4 +/- 4.9 beats/min vs -12.7 +/- 6.6 beats/min, P < 0.005, respectively). Heart rate increased during nighttime (P < 0.02) and was significantly greater than with atenolol treatment (5.0 +/- 7.2 beats/min vs -5.7 +/- 8.0 beats/min, P < 0.001, respectively). These results suggest that the different effects of the two beta-blockers on heart rate and nighttime blood pressure may be attributed to the presence or absence of intrinsic sympathomimetic activity.

A comparison of the ocular hypotensive efficacy and systemic safety of 0.5% levobunolol and 2% carteolol

In a 3-month, double-masked, randomized clinical trial, the ocular hypotensive efficacy and systemic safety of 0.5% levobunolol and 2% carteolol were compared in 59 patients with open-angle glaucoma or ocular hypertension. The overall mean decrease in intraocular pressure was 7.3 mm Hg (27.4%) in the 0.5% levobunolol group and 4.1 mm Hg (14.8%) in the carteolol group. This difference was statistically significant (p = 0.0004). Changes in visual field and cup-disk ratios were few and similar between the groups. Effects on mean heart rate were noted in both treatment groups. The mean decrease in heart rate in the carteolol group was greater (-8.4 beats/min) than in the levobunolol group (-3.1 beats/min). This difference had marginal statistical significance (p = 0.059). We conclude that 0.5% levobunolol and 2% carteolol administered twice daily differ in lowering intraocular pressure as well as in their effects on heart rate.

Effects of ocular carteolol and timolol on plasma high-density lipoprotein cholesterol level

Fifty-eight healthy, normolipidemic adult men participated in a prospective, masked, randomized crossover study designed to compare the effects of two topical nonselective beta-adrenergic antagonists, carteolol and timolol, on plasma high-density lipoprotein cholesterol levels. Two eight-week treatment periods were separated by an eight-week drug-free period. Carteolol 1.0% or timolol 0.5% was used, one drop twice daily, in both eyes without nasolacrimal occlusion. Fresh plasma was assayed for levels of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and apolipoproteins A-I and B-100. With indistinguishable effects on intraocular pressure, carteolol and timolol induced different (P = .013) decrements in high-density lipoprotein cholesterol levels. Carteolol treatment decreased high-density lipoprotein cholesterol levels by 3.3% (-0.04 mmol/l) and raised the ratio of total to high-density lipoprotein cholesterol levels by 4.0% (0.15 unit); timolol treatment decreased high-density lipoprotein cholesterol levels by 8.0% (-0.10 mmol/l) and raised the ratio of total to high-density lipoprotein cholesterol levels by 10.0% (0.37 unit). There was no differential drug effect on the other lipid variables measured. Ocular nonselective beta-adrenergic antagonist therapy can produce clinically relevant decrements in high-density lipoprotein cholesterol levels in healthy men.