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.

[Contact allergy to eyedrops containing beta-blockers]

In six patients (4 women aged 80, 62, 43 and 52 years and 2 men aged 58 and 51 years), who used eyedrops containing beta-blockers for the treatment of glaucoma, allergic contact dermatitis of the eyelids was diagnosed. Three were allergic to metipranolol, 2 to levobunolol and 1 to timolol. In literature, less than 50 cases of hypersensitivity to beta-blockers in eye medication have been reported. There are, however, reasons to assume that sensitization is more frequent: (a) not all patients are referred by the ophthalmologist to the dermatologist; (b) false-negative reactions to patch tests with the commercial preparations and with beta-blockers are not infrequent; (c) they are not routinely tested because beta-blockers are difficult to obtain in pure form; (d) cross-reactions with other beta-blockers are infrequent, and changing to another preparation therefore usually solves the clinical problem. Nevertheless it is advisable to test a battery of beta-blockers (befunolol, levobunolol, metipranolol, timolol) in allergic patients. A test preparation of 2% in water or 3%-10% in petrolatum may be suitable. Control testing in non-exposed individuals is necessary to exclude irritation reactions.

Early conjunctival changes following treatment with metipranolol and preservatives are not reversible with dexamethasone

BACKGROUND

Topical medication for the treatment of glaucoma alters the cellular and extracellular composition of the superficial and deep conjunctival layers. We sought to determine whether, after short-term use of metipranolol with preservatives, subsequent application of steroids or metipranolol without preservatives affects these conjunctival changes.

METHODS

Rabbits received topical metipranolol over a period of 6 months. For the following 2 months, one group received metipranolol without preservatives, and another group steroids. For controls, animals were treated with preservatives only or metipranolol with preservatives for 6 months. Superior bulbar conjunctiva was examined by light microscopy, immunohistochemistry, and transmission electron microscopy.

RESULTS

On light microscopic and immunohistochemical examination of conjunctival specimens from all groups, there was an increase of subepithelial collagen deposition in all treated groups. Treatment with steroids or preservative-free metipranolol did not alter the initial effects. By electron microscopy, additional extracellular matrix changes were seen as well as degenerative changes of tissue fibroblasts.

CONCLUSION

The animal model used was able reliably to produce conjunctival changes following antiglaucomatous therapy. The changes seen were early changes, because there was no increase of inflammatory cells. Steroids did not significantly affect the changes. The beneficial effect of steroids used prior to glaucoma surgery remains controversial.

Metipranolol-associated nongranulomatous anterior uveitis

PURPOSE

To describe the findings in a patient with a nongranulomatous anterior uveitis, presumed to be induced by metipranolol.

METHOD

A 69-year-old woman developed bilateral, nongranulomatous, anterior uveitis while undergoing treatment with metipranolol 0.3% for primary open-angle glaucoma. Four months after resolution of the initial episode, the patient was challenged with metipranolol 0.3% in the right eye.

RESULT

On reinstituting metipranolol 0.3%, the patient once again developed a unilateral, nongranulomatous, anterior uveitis in the challenged eye.

CONCLUSION

Metipranolol 0.3% eyedrops, used to treat primary open-angle glaucoma, appear to cause a nongranulomatous anterior uveitis.

Uveitis associated with topical beta-blockers

OBJECTIVE

To assess the incidence of uveitis associated with topical beta-blockers.

DESIGN

Retrospective cohort study.

SETTING

A computerized database of a health maintenance organization was used to identify patients who were prescribed metipranolol or other beta-blockers.

PATIENTS

Two groups: 1928 patients using 0.3% metipranolol and 3903 patients using other beta-blockers.

MAIN OUTCOME MEASURE

Cases of uveitis were identified by noting a prescription of a topical corticosteroid and then conducting a chart review.

RESULTS

No cases of uveitis were identified among the 5831 patients. The upper limits of the 95% confidence intervals for the incidence of uveitis in cohorts of this size are 1.87 cases per 1000 person-years of exposure for metipranolol and 1.38 for other beta-blockers.

CONCLUSION

Drug-induced uveitis from metipranolol or other beta-blocker administration is a rare event, even if a causal relationship exists.

Acute pulmonary edema associated with ocular metipranolol use

OBJECTIVE

To report a case of pulmonary edema associated with the use of ocular metipranolol, a nonselective beta-blocker.

CASE SUMMARY

A 72-year-old woman with no history of pulmonary or cardiac disease presented to the emergency room with signs and symptoms consistent with cardiogenic pulmonary edema. The patient had used metipranolol eyedrops approximately 1 hour before becoming symptomatic. When rechallenged inadvertently while hospitalized, the patient again became symptomatic. The patient's metipranolol eyedrops then were substituted with betaxolol eyedrops. She continued to be free of symptoms of pulmonary edema at subsequent clinic visits 1, 4, and 6 weeks following discharge.

DISCUSSION

This is the first reported case of pulmonary edema associated with metipranolol. There was a reasonable temporal association between use of the eyedrops and the onset of symptoms. Beta-blockers may cause cardiogenic pulmonary edema secondary to their negative inotropic and negative chronotropic effects. The drug's lipid solubility or a deficiency in the enzyme responsible for its metabolism may have allowed the drug to accumulate to a critical concentration over the 6-week period of use.

CONCLUSIONS

Ocular beta-blockers must be used with caution in patients with relative contraindications to beta-blockade. This case illustrates that these agents must be used prudently even in patients with no history of symptomatic congestive heart failure.

Metipranolol-associated granulomatous iritis

PURPOSE

Topical metipranolol therapy for primary open-angle glaucoma has been associated with anterior granulomatous uveitis in the United Kingdom. We studied granulomatous uveitis reactions to topical metipranolol 0.3% therapy for primary open-angle glaucoma in two patients in the United States.

METHODS

Two patients, aged 71 and 81 years, were given topical metipranolol 0.3% therapy for primary open-angle glaucoma.

RESULTS

Both developed granulomatous uveitis. The iritis was associated with an increase in intraocular pressure in both patients and resolved on discontinuation of the drug. One patient was inadvertently rechallenged with metipranolol, and the iritis recurred.

CONCLUSIONS

Topical metipranolol 0.3% therapy may be associated with the development of granulomatous uveitis and a paradoxical increase in intraocular pressure.

[Development of a withdrawal syndrome in a neonate after long-term therapy of the mother with metipranolol during pregnancy]

The authors describe the withdrawal syndrome of a beta-adrenolytic in neonates manifested above all 10-16 hours after delivery by alternating bradycardia and marked tachycardia independently on the infant's activity. The withdrawal syndromes correlate with the increased heart rate of the mother after delivery. The authors draw attention to the fact that the withdrawal syndrome in the neonate may develop after delivery if the mother used during pregnancy not only addictive drugs affecting the central nervous system but also drugs affecting the cardiovascular system such as the beta-adrenolytic metipranolol.

Metipranolol-induced adverse reactions: I. The rechallenge study

Previously unreported adverse drug reactions can be difficult to detect and it may be even more difficult to establish a cause and effect relationship, particularly if the adverse reactions mimic naturally occurring disease. In a previous paper we reported 29 patients with granulomatous anterior uveitis, blepharoconjunctivitis, periorbital dermatitis, marginal keratitis and elevation in intraocular pressure (IOP), suspected to be caused by metipranolol (Glauline). With the approval of the District Ethics Committee 7 of those patients were rechallenged with metipranolol 0.3% compared to timolol maleate 0.5% in a double blind trial. The 7 metipranolol treated eyes developed an adverse reaction within 14 days. Metipranolol (Glauline) has been conclusively proven to cause granulomatous anterior uveitis, blepharoconjunctivitis and elevation in IOP, adverse effects never previously reported with any of the ophthalmic topical beta-blockers. The multidose preparations of metipranolol (Glauline) in all three strengths 0.1%, 0.3% and 0.6% and the single dose minim preparation of metipranolol 0.6% have now been withdrawn from clinical use in the United Kingdom.

[Are metipranolol eyedrops responsible for intraocular side effects?]

Metipranolol is a beta-blocker that has been used in ophthalmology and in systemic therapy for about 10 years. Reports about reversible uveitis under the product Glauline (metipranolol-containing eye drops) in England were the reason for extensive studies with metipranolol-containing eye drops produced with different methods. Analytical studies concerning the influence of irradiation sterilization on the drug containers, studies on the toxicity of the ophthalmic drug on tissue cultures, and prospective and retrospective clinical studies on 2,800 glaucoma patients were performed. Irradiation sterilization leads to the formation of free radicals on the surface of the containers and, depending on the radiation dose, to a decrease in the pH of the drug solution. In prospective studies involving 1,516 glaucoma patients, no intraocular side effects due to metipranolol-containing eye drops were found. In the retrospective examination including 1,306 glaucoma patients, 19 cases of uveitis were found. Thirteen cases of recurring iritis were diagnosed, which had already been observed before the onset of glaucoma therapy. In 2 cases the iritis led to secondary glaucoma and was treated with metipranolol. In 2 cases glaucoma was treated with pilocarpine (and dipivefrin) and metipranolol concomitantly. One case of rubeosis iridis was incorrectly classified as iritis. One case is possibly related to metipranolol despite the assessment to the contrary by the ophthalmologist in question. Following the results of these studies, an accumulation of cases of uveitis caused by metipranolol can be excluded.

Metipranolol-induced adverse reactions: II. Loss of intraocular pressure control

This paper reviews the behaviour of intraocular pressure (IOP) in glaucomatous eyes treated with metipranolol with and without drug-induced adverse reactions (ADRs). Two hundred and forty seven patients with open angle glaucoma who were receiving the three different strengths of metipranolol (0.1%, 0.3%, and 0.6%) in our Department and the 7 patients who participated in the metipranolol rechallenge trial were included in this study. Out of the 247 patients, there were 52 eyes of 29 patients who showed 78 episodes of ADRs associated with metipranolol. Forty five of these 78 episodes (57.6%) were associated with loss of IOP control. Two of the 7 eyes treated with metipranolol in the rechallenge trial showed loss of IOP control, 1 of them without any signs of ocular inflammation. We further studied all the glaucomatous eyes controlled with metipranolol 0.6% only and 22 eyes were identified with loss of IOP control but without recognisable signs or symptoms of ADR. Five other eyes in this group later developed metipranolol-induced ADRs. The possible pathophysiological mechanisms for the loss of IOP control are discussed and it is suggested that the active drug, metipranolol, could be directly implicated.

Metipranolol-associated granulomatous anterior uveitis

This paper presents for the first time documented evidence, clinical details, and photographic illustrations of metipranolol-associated granulomatous anterior uveitis in 26 eyes of 15 patients being treated for glaucoma. There were 56 episodes of granulomatous anterior uveitis, all associated with large (mutton-fat) keratic precipitates, flare, cells, and 'white eyes' (except in seven episodes). In 30 (53.6%) of these episodes there was loss of control of intraocular pressure. Metipranolol 0.6% was implicated in 54 of the 56 episodes and metipranolol 0.3% in the remaining two. Fifty-one other cases of metipranolol-associated granulomatous anterior uveitis have so far been reported from other parts of the country to the Committee on Safety of Medicines. As a result multidose metipranolol in 0.1%, 0.3%, and 0.6% strengths has been withdrawn from clinical use in the United Kingdom. The pathogenesis of this adverse drug reaction is uncertain.

Glauline (metipranolol) induced uveitis and increase in intraocular pressure

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Efficacy and safety of the combination therapy Pilogel/beta-blocker: interim results

The interim results of a multicentered clinical trial with the combination therapy therapy Pilogel/topical beta-blocker (twice daily) in patients with primary open angle glaucoma or ocular hypertension are discussed. Six patients were treated with Pilogel and a topical beta-blocker for one month. Four out of six patients responded well to the combination therapy. Most patients experienced some difficulty in applying the gel and their eyelids stuck together on awakening. In two patients a superficial punctate keratitis was observed. We found an average decrease in intra-ocular pressure (IOP) of 22.5% 22.5 hours after Pilogel administration, but there was some tendency towards higher evening values compared to morning values. In view of the appearance of a corneal haze as described by Johnson et al. during long-term treatment, longer follow-up is necessary.

Conjunctival keratinisation, an abnormal reaction to an ocular beta-blocker

Conjunctival leucoplakia was induced by the local beta-blocker metipranolol in one case. Withdrawal of the drug and application of all-trans retinoic acid ointment resulted in resolving of the keratinisation. A striking pharmacological resemblance is discovered between metipranolol and practolol. Metipranolol seems to be a less toxic phenol derivative of practolol. Nevertheless, it seems able to act as antigen.

Ocular metipranolol. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in glaucoma and ocular hypertension

Metipranolol is a non-selective beta-adrenoceptor blocking agent used for the topical treatment of elevated intraocular pressure in patients with chronic open angle glaucoma or ocular hypertension. In double-blind comparative studies of up to 4 months duration, metipranolol 0.1 to 0.6% produced comparable reductions in intraocular pressure to timolol 0.25 to 0.5% and levobunolol 0.5%, lowering pressure by about 20 to 29% from baseline. Metipranolol has been well tolerated by most patients, producing only minor changes in objective measurements of ophthalmic status and systemic parameters. Similarly, subjective ophthalmic complaints have been minimal although reports of initial stinging or burning upon instillation have occurred. Further published reports, in which larger numbers of patients are treated over extended periods, are needed to confirm the drug's apparent long term comparative efficacy. Studies of ocular metipranolol to date are encouraging, and the drug demonstrates a lasting intraocular pressure reducing effect with good tolerability. Thus, ocular metipranolol provides a viable alternative to ocular timolol and levobunolol in the topical treatment of chronic open angle glaucoma or ocular hypertension.

[Asthma and beta-blocker eye drops (timolol, metipranolol, carteolol). Inhibition of chronotropic effects of isoprenaline]

Effects of three beta antagonist eye drops are studied in three parallel groups of asthmatic patients. Each ocular topic lowers FEV1 with a maximal effect of -13.4 +/- 2.1% for timolol (n = 15), -17.9 +/- 3.3% for metipranolol (n = 10), and -8.6 +/- 3.0% for carteolol (n = 10). Vital capacity, systolic and diastolic pressure scarcely change, but all three eye drops give a dose dependent sinus bradycardia. Intravenous infusion of isoproterenol (exclusive beta agonist) shows an important inhibition of cardiac receptors by timolol. Doses necessary to increase heart rate of 50% are of 0.242 +/- 0.019 microgram/kg before eye drops are instilled and of 0.647 +/- 0.054 microgram/kg after timolol treatment. This study stresses out the necessity of following recommended doses and respecting carefully classical contra indications of beta blocking agents and specially asthma.

[Changes in lung function following administration of eyedrops containing timolol, metipranolol, pindolol and pilocarpine in healthy probands and patients with mild bronchial asthma]

Lung function was studied double blind and randomized in 5 patients with mild asthma bronchiale and 10 normal adults before and 30, 60 and 90 minutes after one drop of 0.5% Timolol, 0.6% Metipranolol or 0.9% NaCl in each eye. In the asthmatics bronchoconstriction was seen after both beta-receptor blocking agents, more pronounced after Timolol than after Metipranolol. There was a decrease in the forced expiratory volume in one second (FEV1.0) of 32, respectively 18%. No changes were observed in the normal subjects. In a separate study no significant changes were seen in the mean values of 10 other asthmatic subjects after 1% Pindolol, 3% Pilocarpin or 0.9% NaCl. However, in two patients FEV1.0 was reduced by 15% and 20% of the control values after applying Pindolol. In summary, not only beta-receptor-blocking agents without ISA produce a bronchoconstriction in asthmatic subjects, but also beta-blocker with ISA in individual cases.

Levobunolol and metipranolol: comparative ocular hypotensive efficacy, safety, and comfort

Topical levobunolol 0.5% was compared with topical metipranolol 0.6% for efficacy, safety, and comfort in 46 patients with open angle glaucoma or ocular hypertension. The study was of parallel design, randomised, double-masked, and of three months' duration. After a washout interval the study medications were instilled twice daily in both eyes. The overall mean decrease in intraocular pressure (IOP) was approximately 7 mmHg in both groups. More than 90% of patients in both groups successfully completed the study. Both agents caused slight decreases in heart rate and blood pressure. More complaints of burning and stinging were reported in the metipranolol group than in the levobunolol group. This three-month, 46-patient study showed levobunolol 0.5% and metipranolol 0.6% to be similarly effective ocular hypotensive agents.

[Metipranolol 0.1% and pilocarpine 2% as a fixed combination compared to each substance alone in the treatment of glaucoma. A controlled, randomized clinical study comparing the intraindividual effects and tolerance]

A fixed combination of pilocarpine 2% and metipranolol 0.1% was found to have a better pressure-lowering effect than pilocarpine 2% alone or metipranolol 0.1% alone, as well as being tolerated well, both subjectively and objectively. In many cases only the fixed combination was successful in lowering intraocular pressure to tolerable values.

[Therapeutic consequences of glaucoma treatment with different beta blockers in patients with obstructive respiratory tract diseases]

In patients in whom chronic obstructive bronchial disease and chronic glaucoma had been diagnosed, the most important ventilation parameters and intraocular pressures were investigated in a double-blind cross-over study. The airway resistance, the forced expiratory volume within the first second, the thoracic volume, and the mean expiratory flow in these patients exhibited significant differences after treatment with non-cardioselective beta-blocking agents, depending on the beta-receptor stimulating action of this ophthalmic solution (Pindolol 1% eye drops) or without any intrinsic sympathicomimetic action (Metipranolol 0.6% eye drops). There was no fundamental difference in the intraocular pressure-lowering effect of these two locally applied beta-blocking solutions. This study implies that when selecting a beta-blocking ophthalmic solution for anti-glaucoma treatment, the existence of an ISA effect of these eye drops is relevant only to avoid systemic side effects such as bronchopulmonary obstruction.

[Local subjective tolerance of levobunolol and metipranolol in a double-blind comparative study in patients with increased intraocular pressure]

We evaluated the ocular comfort of 0.5% levobunolol hydrochloride and 0.6% metipranolol hydrochloride ophthalmic solutions in a randomized, double-masked, paired-comparison clinical trial. The drugs were given twice daily for 7 days to 16 patients with open-angle glaucoma or ocular hypertension. Patients rated comfort in terms of the severity of burning and/or stinging. For both drugs, the severity rating of ocular discomfort was low, averaging between 1 and 2 on a scale of 0-10. At initial and follow-up visits, the mean severity rating of burning or stinging with metipranolol was 2, slightly greater than the mean score of 1 with levobunolol. At 55% (26 of 47) of the patient visits, the patients rated levobunolol as more comfortable than metipranolol. Metipranolol (Betamann; Mann) was rated as more comfortable than levobunolol at only 9% (4 of 47) of the patient visits. The duration of burning and stinging was also rated as longer lasting with metipranolol treatment than with levobunolol (Vistagan; Pharma-Allergan) treatment. Although little ocular discomfort was reported for either drug, the majority of the patients tested rated levobunolol the more comfortable of the two drugs.

[Effectiveness and tolerance of metipranolol--results of a multi-center long-term study in Switzerland]

The results of this continuing multicenter study revealed a good efficacy and tolerance of Metipranolol used in patients with ocular hypertension and chronic open-angle glaucoma. After 4 weeks' treatment a reduction in average intraocular pressure of 5.6 mmHg could be observed. This favorable effect on pressure values could be confirmed during long-term treatment up to 16 weeks (average reduction in intraocular pressure of 5.9 mmHg equal to 25%). More than 90% of patients treated with 0.1% Metipranolol showed very good or good tolerance. In conclusion, it can be established that 0.1% Metipranolol has also confirmed its value in daily practice and offers an interesting possibility for low-dosage beta-blocker therapy.

[Effect of prolonged administration of beta-blockers on the hemodynamics of patients who have sustained a myocardial infarct]

The effect of prolonged treatment with the beta-blocker trimepranol on left-ventricular function was assessed in patients who survived myocardial infarction. Pulmonary arterial catheterization with a floating catheter was used for hemodynamic investigation. Hemodynamic parameters were compared in the treated (20 patients) and control (20 patients matched for age and infarction site) groups. The treated patients showed a reduction in heart rate and cardiac output at rest, as well as stress-induced elevation of the pulmonary arterial pressure and peripheral resistance. Patients with pulmonary hypertension often demonstrated changes of the pressure curve in the pulmonary artery as a possible manifestation of stress-induced mitral regurgitation. Prolonged treatment with trimepranol is associated with increased incidence of pulmonary hypertension in myocardial infarction survivers. The clinical significance of this observation is yet to be established by further studies. Stress-induced mitral regurgitation associated with a mitral subvalvular dysfunction may occasionally be the cause of elevated pulmonary blood pressure.

The influence of topical beta-blockers on the breakup time

In a double-blind masked study with 100 young and healthy subjects we compared the influence of the beta-blocking agents timolol and metipranol on breakup time and their tolerance. While metipranolol provoked a slight burning sensation, timolol was well tolerated. Both beta-blockers, however, led to an equally enormous reduction in BUT in short-term observations.

[Metabolic effects of a fixed combination (betablocker plus saluretic) in long-term treatment of arterial hypertension (author's transl)]

In 23 patients with essential hypertension of stage I and II according to the WHO, the effects of a fixed combination of a beta-receptor-blocker plus saluretic composed of 20 mg of metipranolol (Disorat 20) and 2.5 mg of butizid (Saltucin) = Torrat on blood pressure and important metabolic parameters (glucose, glucose tolerance, cholesterol, triglyceride, uric acid, plasma potassium and whole body potassium) were tested over a 6-month treatment period.

RESULTS

blood pressure and pulse rate were significantly reduced; bradycardia (pulse rate less than 60/min) was not observed. The metabolic parameters showed no significant changes during the 6-month treatment period. In no case did the therapy have to be discontinued because of undesirable effects. The investigations show that the combination has a good antihypertensive effect with few side-effects and that it has no influence on important metabolic parameters during long-term therapy.