Suicidal attempt with eliglustat overdose

Eliglustat is an orphan medicine used for long-term treatment of Gaucher disease type 1 (GD1) in adults. GD1 is a genetic condition, in which glucosylceramide builds up in the body, typically in liver, spleen, and bone. Clinical signs and symptoms of the disease are anemia, tiredness, easy bruising, hepatosplenomegaly, bone pain, and fractures. Eliglustat works by blocking glucosylceramide synthase (substrate reduction therapy). This medicine is subject to additional safety monitoring by regulatory authorities in the European Union. Scientific literature on eliglustat overdose is not available. We herein describe successful treatment of a suicidal attempt with massive eliglustat overdose. A 29-year-old female with GD1, a poor metabolizer of cytochrome P450 2D6 on a recommended daily dose of 84 mg of eliglustat, had taken 94 capsules of eliglustat (84 mg per capsule). One hour after ingestion of almost 8 g of eliglustat, the patient suffered from somnolence, severe bradycardia (37 bpm), and hypotension (systolic blood pressure of 70 mm Hg). After intravenous administration of atropine (1 mg) and cafedrine/theoadrenaline (100 mg/5 mg) by the called emergency physician, the patient resolved gradually. She remained 24 h with stable hemodynamics at a nearby intensive care unit. During continuous ECG monitoring, increased frequency of supraventricular ectopic activity and a first-degree atrioventricular block were observed. To our knowledge, this is the first case report on a suicidal attempt with eliglustat.

Efficacy and safety of a novel high-dose mesalazine tablet in mild to moderate active ulcerative colitis: a double-blind, multicentre, randomised trial

Background

Adherence to mesalazine treatment is essential for the successful treatment of ulcerative colitis.

Objective

The objective of this study was to compare the efficacy, safety and preference of a novel high-dose 1000 mg mesalazine tablet versus conventional treatment for ulcerative colitis remission.

Methods

This pivotal phase III trial compared one 1000 mg mesalazine tablet (M1000 group) versus two registered 500 mg mesalazine tablets (M2x500 group), both taken three times daily, in patients with mild to moderately active ulcerative colitis. The primary efficacy variable was clinical remission at week 8.

Results

A total of 306 patients were considered for intent-to-treat analysis. Clinical remission was achieved in 45.0% of the patients in the M1000 group versus 41.9% in the M2x500 group (P < 0.001 for non-inferiority). Mucosal healing was achieved by 68.9% of the patients in the M1000 group and 68.4% in the M2x500 group. The majority of patients preferred the intake of one high-dose tablet (47.7%) over two low-dose tablets (10.5%). Oral treatment with high-dose 1000 mg mesalazine tablets was well tolerated without new safety signals.

Conclusions

The novel high-dose 1000 mg mesalazine tablet is effective, non-inferior to the registered 500 mg mesalazine tablet, and safe for ulcerative colitis treatment. It was preferred by a majority of patients and may improve ulcerative colitis treatment adherence.

Randomised clinical trial: mesalazine versus placebo in the prevention of diverticulitis recurrence

BACKGROUND

Previous studies have reached conflicting conclusions regarding the efficacy of mesalazine in the prevention of recurrent diverticulitis.

AIM

To investigate the efficacy and safety of mesalazine granules in the prevention of recurrence of diverticulitis after acute uncomplicated diverticulitis.

METHODS

Two phase 3, randomised, placebo-controlled, double-blind multicentre trials (SAG-37 and SAG-51) investigated mesalazine granules in patients with prior episodes (<6 months) of uncomplicated left-sided diverticulitis. Patients were randomised to receive either 3 g mesalazine once daily or placebo (SAG-37, n=345) or to receive either 1.5 g mesalazine once daily, 3 g once daily or placebo for 96 weeks (SAG-51, n=330). The primary endpoint was the proportion of recurrence-free patients during 48 weeks (SAG-37 and SAG-51) or 96 weeks (SAG-51) of treatment.

RESULTS

Mesalazine did not increase the proportion of recurrence-free patients over 48 or 96 weeks compared to placebo. In SAG-37, the proportion of recurrence-free patients during 48 weeks was 67.9% with mesalazine and 74.4% with placebo (P=.226). In SAG-51, the proportion of recurrence-free patients over 48 weeks was 46.0% with 1.5 g mesalazine, 52.0% with 3 g mesalazine and 58.0% with placebo (P=.860 for 3 g mesalazine vs placebo) and over 96 weeks 6.9%, 9.8% and 23.1% respectively (P=.980 for 3 g mesalazine vs placebo). Patients with only one diverticulitis episode in the year prior to study entry had a lower recurrence risk compared to >1 episode. Safety data revealed no new adverse events.

CONCLUSION

Mesalazine was not superior to placebo in preventing recurrence of diverticulitis.

A Randomised, Double-blind, Placebo-controlled Trial of Trichuris suis ova in Active Crohn's Disease

BACKGROUND AND AIMS

To investigate the efficacy and safety of three different dosages of embryonated, viable eggs of Trichuris suis [TSO] versus placebo for induction of remission in mildly-to-moderately active ileocolonic, uncomplicated Crohn's disease [CD].

METHODS

Adults with active CD [n = 252] randomly received six fortnightly doses of 250, 2500, or 7500 TSO/15 ml suspension/day [TSO 250, TSO 2500, TSO 7500], or 15 ml placebo solution/day, in a double-blind fashion, with 4 weeks' follow-up. Primary endpoint was the rate of clinical remission [Crohn's Disease Activity Index [CDAI] < 150] at end of treatment, ie at Week 12 or withdrawal. Secondary endpoints included the course of clinical remission, rate of clinical response, change in CDAI, change in markers of inflammation, mucosal healing, and Physician's Global Assessment.

RESULTS

Clinical remission at Week 12 occurred in 38.5%, 35.2%, and 47.2% of TSO 250, TSO 2500, and TSO 7500 patients, respectively, and in 42.9% of placebo recipients. TSO induced a dose-dependent immunological response. There was no response regarding laboratory markers of inflammation. Other secondary efficacy variables also showed no advantage of TSO over placebo for treatment of active CD. Administration of TSO did not result in any serious adverse drug reaction. Review of non-serious suspected adverse drug reactions following TSO did not reveal any safety concerns.

CONCLUSIONS

Administration of 250-7500 TSO fortnightly over 12 weeks was safe and showed a dose-dependent immunological response, but no TSO dose showed a clinically relevant effect over placebo for induction of clinical remission or response in mildly-to-moderately active, ileocolonic CD.

Efficacy and safety of a novel high-dose mesalazine tablet in mild to moderate active ulcerative colitis: a double-blind, multicentre, randomised trial

Background

Adherence to mesalazine treatment is essential for the successful treatment of ulcerative colitis.

Objective

The objective of this study was to compare the efficacy, safety and preference of a novel high-dose 1000 mg mesalazine tablet versus conventional treatment for ulcerative colitis remission.

Methods

This pivotal phase III trial compared one 1000 mg mesalazine tablet (M1000 group) versus two registered 500 mg mesalazine tablets (M2x500 group), both taken three times daily, in patients with mild to moderately active ulcerative colitis. The primary efficacy variable was clinical remission at week 8.

Results

A total of 306 patients were considered for intent-to-treat analysis. Clinical remission was achieved in 45.0% of the patients in the M1000 group versus 41.9% in the M2x500 group (P < 0.001 for non-inferiority). Mucosal healing was achieved by 68.9% of the patients in the M1000 group and 68.4% in the M2x500 group. The majority of patients preferred the intake of one high-dose tablet (47.7%) over two low-dose tablets (10.5%). Oral treatment with high-dose 1000 mg mesalazine tablets was well tolerated without new safety signals.

Conclusions

The novel high-dose 1000 mg mesalazine tablet is effective, non-inferior to the registered 500 mg mesalazine tablet, and safe for ulcerative colitis treatment. It was preferred by a majority of patients and may improve ulcerative colitis treatment adherence.

A randomised, double-blind trial comparing budesonide formulations and dosages for short-term treatment of eosinophilic oesophagitis

OBJECTIVE

To investigate the efficacy and safety of two different budesonide formulations (effervescent tablet for orodispersible use (BET) and viscous suspension (BVS)) with different daily dosages for short-term treatment of eosinophilic oesophagitis (EoE).

DESIGN

Adults with active EoE (n=76) randomly received 14 days' treatment with either BET 2×1 mg/day (BET1, n=19) or BET 2×2 mg/day (BET2, n=19), or BVS 2×5 mL (0.4 mg/mL)/day (BVS, n=19) or placebo (n=19) in a double-blind, double-dummy fashion, with a 2-week follow-up. Primary end point was histological remission (mean of <16 eosinophils/mm(2 )hpf). Secondary end points included endoscopy score, dysphagia score, drug safety and patient's preference for drug formulation.

RESULTS

Histological remission occurred in 100%, 94.7% and 94.7% of budesonide (BET1, BET2, BVS, respectively) and in 0% of placebo recipients (p<0.0001). The improvement in total endoscopic intensity score was significantly higher in the three budesonide groups compared with placebo. Dysphagia improved in all groups at the end of treatment; however, improvement of dysphagia persisted only in those treated with BET1 (p=0.0196 vs placebo). There were no serious adverse events. Local fungal infection (stained fungi) occurred in two patients of each budesonide group (10.5%). The effervescent tablet was preferred by 80% of patients.

CONCLUSIONS

BET or BVS was highly effective and safe for short-term treatment of EoE. The 1 mg (twice daily) dosage was equally effective as the 2 mg twice daily dosage. The majority of patients preferred the effervescent tablet formulation.

CLINICALTRIALSGOV NUMBER

NCT02280616; EudraCT number, 2009-016692-29.

Low-dose budesonide for maintenance of clinical remission in collagenous colitis: a randomised, placebo-controlled, 12-month trial

OBJECTIVE

This 1-year study aimed to assess low-dose budesonide therapy for maintenance of clinical remission in patients with collagenous colitis.

DESIGN

A prospective, randomised, placebo-controlled study beginning with an 8-week open-label induction phase in which patients with histologically confirmed active collagenous colitis received budesonide (Budenofalk, 9 mg/day initially, tapered to 4.5 mg/day), after which 92 patients in clinical remission were randomised to budesonide (mean dose 4.5 mg/day; Budenofalk 3 mg capsules, two or one capsule on alternate days) or placebo in a 12-month double-blind phase with 6 months treatment-free follow-up. Primary endpoint was clinical remission throughout the double-blind phase.

RESULTS

Clinical remission during open-label treatment was achieved by 84.5% (93/110 patients). The median time to remission was 10.5 days (95% CI (9.0 to 14.0 days)). The maintenance of clinical remission at 1 year was achieved by 61.4% (27/44 patients) in the budesonide group versus 16.7% (8/48 patients) receiving placebo (treatment difference 44.5% in favour of budesonide; 95% CI (26.9% to 62.7%), p<0.001). Health-related quality of life was maintained during the 12-month double-blind phase in budesonide-treated patients. During treatment-free follow-up, 82.1% (23/28 patients) formerly receiving budesonide relapsed after study drug discontinuation. Low-dose budesonide over 1 year resulted in few suspected adverse drug reactions (7/44 patients), all non-serious.

CONCLUSIONS

Budesonide at a mean dose of 4.5 mg/day maintained clinical remission for at least 1 year in the majority of patients with collagenous colitis and preserved health-related quality of life without safety concerns. Treatment extension with low-dose budesonide beyond 1 year may be beneficial given the high relapse rate after budesonide discontinuation.

TRIAL REGISTRATION NUMBERS

http://www.clinicaltrials.gov (NCT01278082) and http://www.clinicaltrialsregister.eu (EudraCT: 2007-001315-31).

The phosphodiesterase-5-inhibitor udenafil lowers portal pressure in compensated preascitic liver cirrhosis. A dose-finding phase-II-study

BACKGROUND

Phosphodiesterase-5-inhibitors may lower portal pressure.

AIMS

To investigate the effect of the phosphodiesterase-5-inhibitor udenafil on hepatic and systemic haemodynamics in liver cirrhosis.

METHODS

In an open-label phase-II-study, patients with liver cirrhosis Child A/B and hepatic venous pressure-gradient ≥ 12 mmHg received 12.5mg/day, 25mg/day, 50mg/day, 75 mg/day (n = 5, each), or 100mg/day (n = 10) udenafil p.o. for one week. On days 0 and 6, hepatic venous pressure-gradient was measured prior to and one hour after drug ingestion. Endpoints were reduction of hepatic venous pressure-gradient from day 0 pre to day 6 post intake and reduction in the acute setting. Pharmacokinetics were measured in the two lowest dosage groups.

RESULTS

Combining the 75 and 100mg/day groups hepatic venous pressure-gradient reduction after drug intake was 19.9% (p = 0.0006) on day 0. From day 0 pre-dose to day 6 post-dose hepatic venous pressure-gradient decreased by 15.7% (p = 0.040) and in 5/15 patients by ≥ 20% or to <12 mmHg. In the 100mg/day group, mean arterial pressure decreased from 98.9 mmHg by 6.2 mmHg (p = 0.037) from day 0 pre-dose to day 6 post-dose. Heart rates or electrocardiograms were unchanged. Udenafil was eliminated with t1/2 = 25 h.

CONCLUSIONS

Oral application of 75-100mg of the phosphodiesterase-5-inhibitor udenafil lowers portal pressure in the acute setting by about 20% without relevant systemic cardiovascular side effects.

Once versus three times daily dosing of oral budesonide for active Crohn's disease: a double-blind, double-dummy, randomised trial

BACKGROUND

Oral budesonide 9 mg/day represents first-line treatment of mild-to-moderately active ileocolonic Crohn's disease. However, there is no precise recommendation for budesonide dosing due to lack of comparative data. A once-daily (OD) 9 mg dose may improve adherence and thereby efficacy.

METHODS

An eight-week, double-blind, double-dummy randomised trial compared budesonide 9 mg OD versus 3mg three-times daily (TID) in patients with mild-to-moderately active ileocolonic Crohn's disease. Primary endpoint was clinical remission defined as CDAI <150 at week 8 (last observation carried forward).

RESULTS

The final intent-to-treat population comprised 471 patients (238 [9 mg OD], 233 [3 mg TID]). The confirmatory population for the primary endpoint analysis was the interim per protocol population (n=377; 188 [9 mg OD], 189 [3mg TID]), in which the primary endpoint was statistically non-inferior with budesonide 9 mg OD versus 3 mg TID. Clinical remission was achieved in 71.3% versus 75.1%, a difference of -3.9% (95% CI [-14.6%; 6.4%]; p=0.020 for non-inferiority). The mean (SD) time to remission was 21.9 (13.8) days versus 21.4 (14.6) days with budesonide 9 mg OD versus 3 mg TID, respectively. In a subpopulation of 122 patients with baseline SES-CD ulcer score ≥1, complete mucosal healing occurred in 32.8% (21/64) on 9 mg OD and 41.4% (24/58) on 3mg TID; deep remission (mucosal healing and clinical remission) was observed in 26.6% (17/64) and 32.8% (19/58) of patients, respectively. Treatment-emergent suspected adverse drug reactions were reported in 4.6% of 9 mg OD and 4.7% of 3 mg TID patients.

CONCLUSIONS

Budesonide at the recommended dose of 9 mg/day can be administered OD without impaired efficacy and safety compared to 3mg TID dosing in mild-to-moderately active Crohn's disease.

Active eosinophilic esophagitis is associated with impaired elimination of budesonide by cytochrome P450 3A enzymes

BACKGROUND/AIMS

Topically administered glucocorticoids such as budesonide have the potential of being established as first-line medical treatment of eosinophilic esophagitis (EoE). Safety of budesonide is based on high elimination by cytochrome P450 3A (CYP3A) enzymes. We aimed to investigate systemic absorption and elimination of a new budesonide formulation in patients with active EoE in comparison with healthy controls.

METHODS

After single and multiple doses of orodispersible budesonide (4 mg/day) the parent drug, its CYP3A-dependent metabolites, and endogenous cortisol were determined in 12 adult patients with active EoE and 12 healthy controls. An approved ileal-release formulation of budesonide was taken for reference. Molar ratios of metabolite formation in plasma were used as indices of CYP3A metabolic function.

RESULTS

CYP3A-dependent metabolite formation was significantly reduced in patients with active EoE as compared to healthy controls. Impaired biotransformation was reflected by a significantly higher extent of budesonide absorption and elongated elimination half-life in EoE patients. Comparison of morning serum cortisol levels at baseline with those after 1 week of treatment with budesonide revealed a significant decrease in EoE patients but not in healthy subjects.

CONCLUSION

Active EoE is associated with reduced elimination of budesonide via CYP3A, the major subfamily of drug-metabolizing enzymes in humans.

Effect of ursodeoxycholic acid on bile acid profiles and intestinal detoxification machinery in primary biliary cirrhosis and health

BACKGROUND & AIMS

Ursodeoxycholic acid (UDCA) exerts anticholestatic, antifibrotic and antiproliferative effects in primary biliary cirrhosis (PBC) via mechanisms not yet fully understood. Its adequate biliary enrichment is considered mandatory for therapeutic efficacy. However, precise determination of biliary enrichment of UDCA is not possible in clinical practice. Therefore, we investigated (i) the relationship between biliary enrichment and plasma pharmacokinetics of UDCA, (ii) the effect of UDCA on plasma and biliary bile acid composition and conjugation patterns, and (iii) on the intestinal detoxification machinery in patients with PBC and healthy controls.

METHODS

In 11 PBC patients and 11 matched healthy subjects, cystic bile and duodenal tissue were collected before and after 3 weeks of administration of UDCA (15 mg/kg/day). Extensive pharmacokinetic profiling of bile acids was performed. The effect of UDCA on the intestinal detoxification machinery was studied by quantitative PCR and Western blotting.

RESULTS

The relative fraction of UDCA and its conjugates in plasma at trough level[x] correlated with their biliary enrichment[y] (r=0.73, p=0.0001, y=3.65+0.49x). Taurine conjugates of the major hydrophobic bile acid, chenodeoxycholic acid, were more prominent in bile of PBC patients than in that of healthy controls. Biliary bile acid conjugation patterns normalized after treatment with UDCA. UDCA induced duodenal expression of key export pumps, BCRP and P-glycoprotein.

CONCLUSIONS

Biliary and trough plasma enrichment of UDCA are closely correlated in PBC and health. Taurine conjugation may represent an adaptive mechanism in PBC against chenodeoxycholic acid-mediated bile duct damage. UDCA may stabilize small intestinal detoxification by upregulation of efflux pumps.

3g mesalazine granules are superior to 9mg budesonide for achieving remission in active ulcerative colitis: a double-blind, double-dummy, randomised trial

BACKGROUND AND AIMS

Budesonide may be an effective therapy for mild-to-moderately active ulcerative colitis (UC). This study aimed to demonstrate non-inferiority for oral 9mg budesonide once daily (OD) versus 3g mesalazine granules OD.

METHODS

This was an eight-week randomised, double-blind, double-dummy, multicentre study in which patients with mild-to-moderately active UC, defined as Clinical Activity Index (CAI) ≥6 and Endoscopic Index (EI) ≥4, received budesonide (Budenofalk® 3mg capsules×3) or mesalazine (Salofalk® 1000mg granules×3). The primary endpoint was clinical remission at week 8 (CAI ≤4 with stool frequency and rectal bleeding subscores of "0").

RESULTS

343 patients were randomised (177 budesonide, 166 mesalazine). Fewer patients achieved the primary endpoint with budesonide versus mesalazine (70/177 [39.5%] versus 91/166 [54.8%]) with a difference in proportions of -15.3% (95% CI [-25.7%, -4.8%]; p=0.520 for non-inferiority). The median time to first resolution of symptoms was 14.0 days (budesonide) and 11.0 days (mesalazine) (hazard ratio 1.19; 95% CI [0.94, 1.51]). Mucosal healing was observed in 54/177 (30.5%) budesonide patients versus 65/166 (39.2%) mesalazine patients, a difference of -8.6% (95% CI [-18.7%, 1.4%]; p=0.093). The incidences of adverse events (budesonide 26.6%, mesalazine 25.3%) and serious adverse events (budesonide 1.7%, mesalazine 1.2%) were similar.

CONCLUSIONS

Once-daily 3g mesalazine administered as granules is superior to 9mg budesonide OD administered as capsules for achieving remission in mild-to-moderately active UC. However, it is noteworthy that remission of UC was attained in about 40% of budesonide-treated patients with a rapid onset of resolution.

Randomised clinical trial: a comparative dose-finding study of three arms of dual release mesalazine for maintaining remission in ulcerative colitis

BACKGROUND

Comparative data regarding different regimens of oral mesalazine (mesalamine) for maintaining remission in ulcerative colitis are limited.

AIM

To evaluate whether 3.0 g mesalazine once-daily (OD) is superior to the standard treatment of 0.5 g mesalazine three times daily (t.d.s.) and to prove the therapeutic equivalence of OD vs. t.d.s. dosing of total 1.5 g mesalazine for remission maintenance in patients with ulcerative colitis.

METHODS

A 1-year, multicentre, double-blind, double-dummy study was undertaken in patients with endoscopically and histologically confirmed ulcerative colitis in remission. Patients were randomised to oral mesalazine 3.0 g OD, 1.5 g OD or 0.5 g t.d.s. The primary efficacy endpoint was the proportion of patients still in clinical remission at the final visit, with clinical relapse being defined as CAI score >4 and an increase of ≥3 from baseline.

RESULTS

The primary efficacy endpoint occurred in 162/217 3.0 g OD patients (75%), 129/212 1.5 g OD patients (61%) and 150/218 0.5 g t.d.s. patients (69%) in the intention-to-treat population, and in 152/177 (86%), 121/182 (67%) and 144/185 (78%) in the per protocol population respectively; 3.0 g OD was superior to both low-dose regimens for the primary endpoint (i.e. P < 0.001, 3.0 g OD vs. 1.5 g OD; P = 0.024, 3.0 g OD vs. 0.5 g t.d.s.; superiority test, per protocol population). Safety analysis, including comprehensive renal monitoring, revealed no concern in any treatment group.

CONCLUSION

Mesalazine 3.0 g once daily was the most effective dose for maintenance of remission in ulcerative colitis of the three regimens assessed, with no penalty in terms of safety.

Budesonide 9 mg is at least as effective as mesalamine 4.5 g in patients with mildly to moderately active Crohn's disease

BACKGROUND & AIMS

Comparative data on budesonide vs mesalamine for the treatment of mild-to-moderately active Crohn's disease (CD) are sparse. We assessed the efficacy and safety of each therapy in patients with mildly to moderately active CD.

METHODS

We performed a randomized, double-blind, double-dummy, 8-week, multicenter study in which 309 patients with mildly to moderately active CD received pH-modified-release oral budesonide (9 mg/day once daily or 3 mg/day 3 times daily) or Eudragit-L-coated oral mesalamine (4.5 g/day).

RESULTS

The primary efficacy variable, clinical remission (defined as Crohn's Disease Activity Index ≤150), at the final visit occurred in 69.5% (107 of 154) of patients given budesonide vs 62.1% (95 of 153) of patients given mesalamine (difference, 7.4%; 95% repeated confidence interval, -4.6% to 18.0%; P = .001 for noninferiority). Clinical remission rates did not differ significantly between the 2 budesonide groups. Treatment response, defined as Crohn's Disease Activity Index of 150 or less and/or a decrease of 70 or more (Δ70) or 100 or more (Δ100) points from baseline to final visit, did not differ significantly between patients given budesonide vs mesalamine (Δ70, P = .11; Δ100, P = .15), or between the 2 budesonide groups (Δ70, P = .38; Δ100, P = .78). No other efficacy end points differed significantly between groups. Discontinuation because of adverse events occurred in 3% and 5% of budesonide- and mesalamine-treated patients, respectively. There were no clinically relevant differences in adverse events between the 2 budesonide groups.

CONCLUSIONS

Budesonide (9 mg/day) was numerically, but not statistically, more effective than Eudragit-L-coated mesalamine (4.5 g/day) in patients with mildly to moderately active CD. Budesonide (9 mg/day), administered once daily, was as effective as the standard (3 times daily) regimen.

Clinical trial: a novel high-dose 1 g mesalamine suppository (Salofalk) once daily is as efficacious as a 500-mg suppository thrice daily in active ulcerative proctitis

BACKGROUND

Mesalamine suppositories are first-line therapy in active ulcerative proctitis; the standard regime still recommends multiple doses per day. The primary objective of this study was to show the noninferiority of once-daily administration of a novel 1 g mesalamine suppository versus thrice-daily administration of the 0.5 g mesalamine suppository.

METHODS

This was a single-blind (investigator-blinded), randomized, multicenter, comparative, Phase III clinical trial. Patients with mild to moderately active ulcerative proctitis inserted either one mesalamine 1 g suppository at bedtime or one mesalamine 0.5 g suppository thrice daily over a 6-week period. The primary endpoint was rate of remission (Disease Activity Index below 4).

RESULTS

In all, 354 patients were evaluable for safety and per-protocol analysis. The new regimen demonstrated noninferiority: The percentage of patients with remission was 87.9% for the once-daily 1 g mesalamine suppository and 90.7% for the thrice-daily 0.5 g mesalamine suppository. Each regimen resulted in prompt cessation of clinical symptoms (e.g., median time to ≤3 stools per day (all without blood): 5 days in the 1 g mesalamine once-daily and 7 days in the 0.5 g mesalamine thrice-daily group). Patients preferred applying suppositories once a day.

CONCLUSIONS

In active ulcerative proctitis the once-daily administration of a 1 g mesalamine suppository is as effective and safe, yet considerably more convenient, than the standard thrice-daily administration of a 0.5 g mesalamine suppository.

Azathioprine versus mesalazine for prevention of postoperative clinical recurrence in patients with Crohn's disease with endoscopic recurrence: efficacy and safety results of a randomised, double-blind, double-dummy, multicentre trial

OBJECTIVE

The aim of the study was to compare azathioprine versus mesalazine tablets for the prevention of clinical recurrence in patients with postoperative Crohn's disease (CD) with moderate or severe endoscopic recurrence.

METHODS

This was a 1 year, double-blind, double-dummy, randomised study which took place in 21 gastroenterology centres in Austria, the Czech Republic, Germany and Israel. The study participants were 78 adults with CD who had undergone resection with ileocolonic anastomosis in the preceding 6-24 months without subsequent clinical recurrence and with a Crohn's disease activity index (CDAI) score <200, but with moderate or severe endoscopic recurrence. The study drugs were azathioprine 2.0-2.5 mg/kg/day or mesalazine 4 g/day over 1 year. The primary end point was therapeutic failure during 1 year, defined as a CDAI score > or = 200 and an increase of > or = 60 points from baseline, or study drug discontinuation due to lack of efficacy or intolerable adverse drug reaction.

RESULTS

Treatment failure occurred in 22.0% (9/41) of azathioprine-treated patients and 10.8% (4/37) of mesalazine-treated patients, a difference of 11.1% (95% CI -5.0% to 27.3%, p=0.19). Clinical recurrence was significantly less frequent with azathioprine versus mesalazine (0/41 (0%) vs 4/37 (10.8%), p=0.031), whereas study drug discontinuation due to adverse drug reactions only occurred in azathioprine-treated patients (9/41 (22.0%) vs 0%, p=0.002). The proportion of patients showing > or = 1 point reduction in Rutgeerts score between baseline and month 12 was 63.3% (19/30) and 34.4% (11/32) in the azathioprine and mesalazine groups, respectively (p=0.023).

CONCLUSIONS

In this population of patients with postoperative CD at high risk of clinical recurrence, superiority for azathioprine versus mesalazine could not be demonstrated for therapeutic failure.

Pharmacokinetics and pharmacodynamic action of budesonide after buccal administration in healthy subjects and patients with oral chronic graft-versus-host disease

Buccal administration of budesonide (mouthwash) may be effective as a topical add-on therapy in patients with oral chronic graft-versus-host disease (cGVHD). Safety of approved oral budesonide is based on high intestinal and hepatic extraction by cytochrome P450 3A (CYP3A) enzymes. The purpose of this study was to evaluate the presystemic extraction and pharmacodynamic action of buccal budesonide. Oral budesonide (3 mg) was taken as reference to which various single and multiple dose regimens of buccal budesonide were compared. Budesonide and the 2 main CYP3A-dependent metabolites (6beta-hydroxybudesonide, 16alpha-hydroxyprednisolone) were analyzed in blood and urine along with the drug's effect on endogenous cortisol in 12 healthy subjects and 7 patients with oral cGVHD. We assessed CYP3A-dependent metabolites in both healthy subjects and patients after buccal budesonide. Whereas systemic exposure to budesonide was markedly lower in healthy subjects after the mouthwash compared to oral dosing (mean relative bioavailability 18%-36%), the systemic concentrations thereafter in patients were as high as those after the identical dose of oral budesonide. Reduced buccal CYP3A activity (lower inactivation of budesonide) in patients contributed to this remarkable difference. Endogenous cortisol was suppressed in some patients during 1 week of continuous treatment with buccal budesonide (3 x 3 mg per day). We are the first to report the biotransformation of budesonide via CYP3A enzymes after buccal drug administration. Only 2% of a buccal dose of budesonide achieves systemic circulation in healthy individuals; that fraction is 10% in patients with oral cGVHD, probably because of alterations in drug uptake and metabolization.

Effect of high-dose metronidazole on pharmacokinetics of oral budesonide and vice versa: a double drug interaction study

Recent case reports suggest that addition of high-dose metronidazole might be associated with elevated plasma concentrations of substrates of cytochrome P450 (CYP) 3A. Because patients with fistulizing Crohn's disease benefit by using high doses of metronidazole for prolonged periods, this study's primary aim was to evaluate the effect of high-dose metronidazole on the pharmacokinetics of oral budesonide, a sensitive substrate of CYP3A commonly prescribed in acute inflammatory bowel disease. Twelve healthy adults received 1.5 g metronidazole per day over 1 week. The CYP3A-dependent metabolic profile of an oral dose of budesonide (3 mg) and that of endogenous cortisol were compared intraindividually before and after administration of metronidazole. There was neither a significant effect of high-dose metronidazole on the area under the plasma concentration-time curve (AUC) of budesonide (90% confidence interval, 79%-115%) nor on the AUC ratios of 6beta-hydroxybudesonide/budesonide and 16alpha-hydroxyprednisolone/budesonide. In parallel, metronidazole did not significantly alter formation of 6beta-hydroxycortisol. Vice versa, budesonide did not affect the AUC of metronidazole (90% confidence interval, 91%-100%). The authors conclude that in contrast to concomitant intake of other imidazoles such as ketoconazole, concomitant intake of metronidazole may not lead to serious safety concerns due to elevated systemic concentrations of the glucocorticoid budesonide.

A clinical trial on absorption and N-acetylation of oral and rectal mesalazine

BACKGROUND

Mesalazine (5-ASA) is a standard treatment for ulcerative colitis. Extent of absorption and N-acetylation determine systemic exposure to 5-ASA, and are thereby relevant for the safety of the treatment. The aim of the study was to compare absorption and N-acetylation of 5-ASA following rectal or oral drug administration. Healthy subjects were compared to patients with ulcerative colitis to evaluate the impact of chronic inflammation of colorectal mucosa on disposition of 5-ASA.

MATERIALS AND METHODS

First, 12 healthy adults were randomized to receive 2 g of 5-ASA by each of four different formulations: oral delayed release granules, 30 mL enema, 60 mL rectal foam, and 120 mL rectal foam. Second, 12 patients with active ulcerative colitis received 60 mL rectal foam. Pharmacokinetic analysis was performed by determination of 5-ASA and its acetylated, pharmacologically inactive metabolite (Ac-5-ASA) in plasma and urine.

RESULTS

First, systemic exposure to 5-ASA was markedly lower after rectal drug administration as compared to oral dosing (P < 0.001; e.g. median relative bioavailability of 60 mL rectal foam: 36%). Second, N-acetylation of rectal 5-ASA was lower in patients than in healthy subjects [area under the curve (AUC) ratio Ac-5-ASA/5-ASA: 1.6 +/- 0.5 vs. 2.3 +/- 0.4, mean +/- SD, P < 0.01]. High peak plasma concentrations of 5-ASA were correlated with high microscopic disease activity (r = 0.67, P < 0.05).

CONCLUSIONS

Rectal delivery of 5-ASA results in low systemic drug exposure with potentially reduced toxicity in comparison with oral drug administration. Chronic inflammation of colorectal mucosa might be a relevant source of variability in pharmacokinetics of 5-ASA.

Monitoring of Thiopurine Methyltransferase Activity in Postsurgical Patients With Crohn's Disease During 1 Year of Treatment With Azathioprine or Mesalazine

Thiopurine methyltransferase (TPMT) activity determines biotransformation of azathioprine and, thereby, drug efficacy and safety. Evaluation of a possible long-term effect of mesalazine or azathioprine on TPMT activity is of particular clinical importance because both drugs can to be given for several years in inflammatory bowel disease. Monitoring of TPMT activity and three thiopurine metabolites was performed prospectively during a 1 year postoperative period in 21 patients with Crohn's disease randomly assigned to azathioprine (2.0-2.5 mg/kg per day) or mesalazine (4 g/day). TPMT activity did not change significantly within each treatment group during 52 weeks. At any study visit, TPMT activity was not different between 13 patients on azathioprine and eight patients on mesalazine. Concentrations of 6-thioguanine nucleotides (6-TGN, active moiety of azathioprine) and 6-methyl-mercaptopurine ribonucleotides (6-MMPR) did not alter significantly during the observation period, except for a slight decrease in 6-TGN levels when comparing the first with the last visit. In this first report of serial monitoring of 6-methyl-thioguanine nucleotides (6-MTGN) in patients with inflammatory bowel disease taking azathioprine, high levels of 6-TGN were correlated with high levels of 6-MTGN, with the mean 6-TGN:6-MTGN ratio being 2.4. In a well-standardized clinical setting of inflammatory bowel disease, neither mesalazine nor azathioprine significantly affected TPMT activity during a whole year of treatment.

Multidrug resistance 1 genotype and disposition of budesonide in early primary biliary cirrhosis

BACKGROUND

Budesonide, which is a dual substrate of P-glycoprotein, the product of the multidrug resistance 1 (MDR1) gene, and cytochrome P450 3A (CYP3A) has been proposed for treatment of early primary biliary cirrhosis (PBC). Recently, MDR1 gene polymorphisms have been discussed as a potential cause of glucocorticoid resistance. We tested the hypothesis that MDR1 gene polymorphisms affect absorption of oral budesonide.

METHODS

In 21 patients with histologically proven early-stage (I/II) PBC and nine healthy subjects, we evaluated the impact of MDR1 single nucleotide polymorphisms (2,677G>T,A and 3,435C>T) on disposition of a single oral dose of 3 mg budesonide. CYP3A5 gene polymorphisms (6,986A>G) were analyzed in parallel.

RESULTS

In MDR1 2,677 GG and 3,435 CC genotypes, absorption and elimination of budesonide were not significantly different from those in corresponding homozygous variants. Peak plasma levels and areas under the plasma concentration time curves (AUC) of budesonide were not lower in MDR1 3,435 CC with putatively high intestinal expression of P-glycoprotein than in MDR1 3,435 TT. Interestingly, in two CYP3A5*1/*3 carriers with high enzyme activity, lower AUC was noted than in 28 CYP3A5*3/*3 carriers with a deficient enzyme.

CONCLUSION

Common MDR1 gene polymorphisms do not affect disposition of budesonide in early PBC.

Pharmacokinetics and pharmacodynamic action of budesonide in children with Crohn's disease

BACKGROUND

Budesonide is effective as initial therapy of mild to moderate Crohn's disease in adults. Superior tolerability to conventional corticosteroids might be attributed to extensive first-pass metabolism of budesonide by cytochrome P450 3A.

AIM

To evaluate biotransformation and pharmacodynamic action of budesonide in children.

METHODS

Drug disposition and effects on endogenous cortisol were evaluated in 12 children with Crohn's disease (5-15 years) after first intake of 3 mg budesonide (single dose), and again after 1 week of thrice daily dosing (steady-state). The parent drug and cytochrome P450 3A-dependent metabolites were analysed in blood and urine.

RESULTS

Pharmacokinetic parameters of budesonide following single-dose administration (e.g. AUC(0-infinity) 7.7+/-5.1 h ng/mL, C(max) 1.8+/-1.2 ng/mL) did not change upon multiple dosing. Overall systemic elimination of budesonide reflected by clearance and half-life was not different between children and adults. After 1 week of treatment reversible adrenal suppression was observed - most pronounced in children aged below 12 years.

CONCLUSIONS

Disposition of oral budesonide appears to be similar between children and adults, but the doctor has to be aware of an increased risk for adrenal suppression in paediatric patients.

No relevant effect of ursodeoxycholic acid on cytochrome P450 3A metabolism in primary biliary cirrhosis

Induction of cytochrome P450 3A (CYP3A) has been suggested as a mechanism of action of ursodeoxycholic acid (UDCA) in cholestasis. CYP3A is of key importance in human drug metabolism, being involved in presystemic extraction of more than 50% of all drugs currently available and of various endogenous compounds. Therefore, we compared the induction potential of UDCA with that of the prototypical inducer rifampicin in a human model study with the CYP3A substrates budesonide and cortisol. Twelve patients with early-stage primary biliary cirrhosis and eight healthy volunteers were treated with UDCA (15 mg/kg daily) for 3 weeks and subsequently with rifampicin (600 mg/d) for 1 week. Extensive pharmacokinetic profiling of oral budesonide (3 mg) was performed by determination of budesonide and phase I metabolites (6beta-hydroxybudesonide, 16alpha-hydroxyprednisolone) in plasma and urine at baseline and at the end of each treatment. In parallel, urinary 6beta-hydroxycortisol, a validated marker of CYP3A induction, was determined. UDCA did not affect biotransformation of budesonide and urinary excretion of 6beta-hydroxycortisol either in patients or in healthy volunteers. Ratios of areas under plasma concentration-time curves (AUC(0-12 h) during UDCA/AUC(0-12 h) before UDCA) of both metabolites were not higher than those of budesonide itself. In contrast, administration of rifampicin markedly induced CYP3A metabolism, resulting in abolished budesonide plasma levels and high urinary excretion of 6beta-hydroxycortisol. Metabolite formation was enhanced by rifampicin, but not by UDCA (e.g., AUC(16alpha-hydroxyprednisolone)/AUC(budesonide) in patients: baseline, 8.6 +/- 3.9; UDCA, 10.7 +/- 7.1; rifampicin, 527.0 +/- 248.7). In conclusion, UDCA is not a relevant inducer of CYP3A enzymes in humans.

Pharmacokinetics of mesalazine pellets in children with inflammatory bowel disease

Mesalazine is a first-line drug in pediatric inflammatory bowel disease (IBD), and is customarily used to induce and maintain remission in mild to moderate disease. In children, pharmacokinetic data are scarce, and dosage recommendations are largely extrapolated from studies in adults. Aim of the study was to obtain the pharmacokinetic profile of a new mesalazine pellet formulation in children with ulcerative colitis and Crohn's colitis. A single oral dose of 20 mg/kg mesalazine was administered to 13 patients (age 6-16 years). Serial blood and urine sampling for determination of mesalazine and acetylmesalazine was performed before and during 24 hours following ingestion. Maximum plasma concentration of mesalazine (Cmax) was 1332 ng/mL (geometric mean, geometric coefficient of variation [CV]: 0.57), obtained 3.7 hours (tmax; CV: 0.31) after drug administration. Systemic exposure as determined by area under the plasma concentration-time curve (AUC(0-infinity) ) was 8712 ng/ml*h (CV: 0.44). Terminal half-life of elimination of mesalazine was 3.5 hours (t(1/2); CV: 1.43). This study presents extensive pharmacokinetic data on mesalazine in children with mild-moderately active ulcerative colitis and Crohn's colitis. In comparison with previous experience in adults, pharmacokinetics of mesalazine administered as pellets appear to be similar in both populations.

Identification of budesonide and prednisone as substrates of the intestinal drug efflux pump P-glycoprotein

Steroid resistance is a major problem in the management of patients with inflammatory bowel disease. In Crohn disease, poor response to corticosteroids has been related to increased expression of the drug efflux pump, P-glycoprotein. However, it has not been investigated thoroughly whether corticosteroids commonly used for drug therapy in inflammatory bowel disease are substrates of P-glycoprotein. We tested the hypothesis that budesonide and prednisone are substrates of P-glycoprotein thereby possibly contributing to variable therapeutic effects. Polarized, basal to apical transport of [3H]budesonide and [3H]prednisone was studied in monolayers of L-MDR1 cells (LLC-PK1 cells stably transfected with human MDR1 cDNA) and Caco-2 cells, both of which express P-glycoprotein in their apical membrane. Drug transport was measured during 4 hours at substrate concentrations of 5 microM. Net transport rates and permeability coefficients were calculated. Inhibition of P-glycoprotein-mediated transport across Caco-2 monolayers was determined after addition of the P-glycoprotein inhibitor PSC-833. The net transport rate from the basolateral to the apical side was significantly higher in L-MDR1 than in LLC-PK1 cells for both budesonide and prednisone. Apparent permeability coefficients of budesonide and prednisone reflected polarized transport from basal to apical. PSC-833 inhibited the polarized transport of both corticosteroids. In conclusion, budesonide and prednisone were identified as substrates of the intestinal drug efflux pump, P-glycoprotein. Therefore, drug secretion via P-glyco-protein into gut lumen might play a more important role in pharmacokinetics and pharmacodynamics of these corticosteroids than currently appreciated in gastroenterological practice.

Inhibition of cytochrome P450 3A: relevant drug interactions in gastroenterology

Cytochrome P450 3A (CYP3A) is involved in biotransformation of more than half of all drugs currently available. Drug interactions by inhibition of CYP3A are of major interest in patients receiving combinations of drugs. Some interactions with CYP3A inhibitors also involve inhibition of the multidrug export pump, P-glycoprotein. An increasing number of adverse drug reactions might be avoided on the basis of knowledge about CYP3A substrates and inhibitors. This article summarizes some examples of such interactions relevant to gastroenterologists. Serious cases by coadministration of CYP3A inhibitors resulting in acute hepatitis, hypotension, rhabdomyolyis, torsade de pointes, sedation, or ergotism are presented: interactions with azole antifungals (ketoconazole, itraconazole, fluconazole), HIV protease inhibitors (ritonavir, indinavir, saquinavir, nelfinavir), macrolide antibiotics (clarithromycin, erythromycin), and grapefruit juice. In addition, 1 case is reported who presented the highest trough levels of the CYP3A substrate budesonide in serum ever measured. Practitioners have to be aware of the high potential of metabolic drug interactions when they prescribe a CYP3A inhibitor. It is wise to check carefully comedication in patients complaining of side effects with substrates of CYP3A.

Systematic review: ursodeoxycholic acid--adverse effects and drug interactions

BACKGROUND

Ursodeoxycholic acid is increasingly being used for the treatment of chronic cholestatic liver diseases. It appears to be generally well tolerated, but a systematic review on drug safety is lacking.

AIM

As experimental data suggest a role of bile acids in the regulation of hepatic drug metabolism at both the transcriptional and post-transcriptional level, the literature was screened for adverse drug reactions and drug interactions related to ursodeoxycholic acid.

METHODS

A systematic review of the literature was performed using a refined search strategy to evaluate the adverse effects of ursodeoxycholic acid and its interactions with other drugs.

RESULTS

Ursodeoxycholic acid caused diarrhoea in a small proportion of patients. Rare skin reactions were due to drug adjuvants rather than the active substance. Decompensation of liver cirrhosis was reported after the administration of ursodeoxycholic acid in single cases of end-stage primary biliary cirrhosis. Recurrent right upper quadrant abdominal pain was incidentally observed. The absorption of ursodeoxycholic acid was impaired by colestyramine, colestimide, colestipol, aluminium hydroxide and smectite. Metabolic drug interactions were reported for the cytochrome P4503A substrates, ciclosporin, nitrendipine and dapsone.

CONCLUSIONS

Ursodeoxycholic acid is generally well tolerated. Drug absorption interactions with anion exchange resins deserve consideration. Metabolic interactions with compounds metabolized by cytochrome P4503A are to be expected.

High variation of tioguanine absorption in patients with chronic active Crohn's disease

BACKGROUND

Tioguanine (thioguanine) has been suggested as a therapeutic alternative for patients with Crohn's disease resistant or intolerant to azathioprine or mercaptopurine. However, pharmacokinetic data on tioguanine in inflammatory bowel disease are missing.

AIM

To determine the disposition of three different 40 mg tablet preparations of tioguanine in patients with Crohn's disease.

METHODS

Six patients with chronic active Crohn's disease were included in a randomized, cross-over, single-dose study. Pharmacokinetic analysis was based on plasma concentrations of tioguanine during 6 h after dosing. Tioguanine was measured by a validated high-pressure liquid chromatographic method.

RESULTS

The areas under the curve (AUC) varied 4-7-fold between patients. In two patients, tioguanine was not detected in plasma following the intake of one of the three tablets; another patient did not absorb tioguanine in two of the three different preparations. No significant differences were found in the AUC and Cmax values between the three tablets. In all patients, there was a second peak in plasma concentration following a meal 3 h after drug administration.

CONCLUSIONS

The absorption of tioguanine is highly variable in patients with Crohn's disease, which may be responsible for treatment failure. Therapy with tioguanine may be improved by monitoring tioguanine nucleotides as a surrogate parameter of efficacy.

Pharmacokinetics and pharmacodynamic action of budesonide in early- and late-stage primary biliary cirrhosis

Budesonide has been discussed as a potential treatment option in primary biliary cirrhosis (PBC). Therefore, we studied the pharmacokinetics and pharmacodynamics of budesonide in patients with PBC stage I/II and stage IV. Twelve patients with early PBC stage I/II and 7 patients with PBC stage IV under continuous treatment with ursodeoxycholic acid (UDCA) were enrolled in an exploratory trial. Each patient received oral budesonide for 3 weeks at weekly increasing dosages of 3 mg once to thrice per day. Budesonide and cortisol plasma levels, urinary cortisol excretion, serum liver tests, and immunoglobulins were determined on days 1, 7, and 21 of the study. Patients with PBC stage IV showed significantly higher peak plasma concentrations (4.9 +/- 3.5 vs. 1.5 +/- 0.4 ng/mL; P <.05) and areas under the plasma concentration-time curves (AUC) (23.2 +/- 16.8 vs. 5.1 +/- 1.4 hours. ng/mL, P <.01, total AUC extrapolated to infinity [AUC(0- infinity )]) after a single dose of 3 mg budesonide when compared with patients with PBC stage I/II. Equally, AUC of budesonide were significantly increased under a multiple dose regimen on day 21 (14.0 +/- 11.6 vs. 5.0 +/- 1.9 hours. ng/mL, P <.01, AUC at steady state from dosing time to 8 hours [AUC(ss,0-8 h)]). Higher levels of budesonide were related to a significant decrease in plasma cortisol and reduction of urinary cortisol excretion in patients with stage IV disease. Two patients with stage IV disease developed portal vein thrombosis (PVT). In conclusion, administration of budesonide leads to markedly elevated plasma levels in cirrhotic patients with PBC associated with serious adverse drug reactions. Thus, further evaluation of combined treatment with UDCA may be considered in early-stage PBC but not in cirrhotic patients with PBC.

Influence of age and cytochrome P450 2C9 genotype on the steady-state disposition of diclofenac and celecoxib

OBJECTIVE

To analyse the influence of age and cytochrome P450 (CYP) 2C9 genotype on the steady-state disposition of the standard NSAID diclofenac and the new COX-2 selective inhibitor celecoxib, both of which are metabolised by the polymorphically expressed CYP2C9.

DESIGN

Double-blind randomised crossover study under steady-state conditions.

SUBJECTS

12 young (age 32 +/- 5 years, bodyweight 71 +/- 12kg; mean +/- SD) and 12 elderly (68 +/- 2 years, 82 +/- 15kg) healthy, drug-free, nonsmoking Caucasians of both sexes.

METHODS

All subjects received oral celecoxib (200mg twice daily) and diclofenac (75mg twice daily) for 15 days separated by a drug-free interval of at least 3 weeks. Following the last morning dose, multiple blood samples were taken for 25 hours. Concentrations of celecoxib and diclofenac were measured by specific and sensitive high performance liquid chromatography. Identification of CYP2C9 genotype was performed by genomic DNA sequencing. Pharmacokinetic parameters for total and unbound drugs were individually analysed by noncompartmental techniques.

RESULTS

For diclofenac, area under the concentration-time curve over the dosage interval (AUC(tau)) was larger in young subjects (3.2 +/- 1.0 mg * h/L) than in older individuals (2.4 +/- 0.4 mg * h/L; p < 0.05). As the terminal half-life (t((1/2)Z)) was very similar in both groups (3.9 +/- 4.4 vs 3.5 +/- 3.3 hours), either less complete absorption in the elderly or their higher bodyweight could account for the difference. For celecoxib, AUC(tau) (5.8 +/- 1.7 vs 5.6 +/- 2.3 mg * h/L) and t((1/2)z) (11.8 +/- 8.7 vs 11.2 +/- 2.9 hours) were almost identical in young and older subjects. Plasma protein binding of both NSAIDs was unaffected by age, and apparent oral clearances for unbound drugs were not different between the two groups of healthy subjects. When considering the genotype of all individuals (CYP2C9*1/*1, n = 10; CYP2C9*1/*2, n = 6; CYP2C9*2/*2, n = 2; CYP2C9*1/*3, n = 4; CYP2C9*3/*3, n = 1), no association with any pharmacokinetic parameter of either drug was apparent. Moreover, there was no significant correlation between the AUC values of celecoxib and diclofenac.

CONCLUSIONS

Age and CYP2C9 genotype do not significantly affect the steady-state disposition of celecoxib and diclofenac. This would indicate that both drugs need no dosage reduction in the elderly (at least up to 75 years) and that, besides CYP2C9, additional CYP species contribute to the elimination of both agents.

Effects of celecoxib and diclofenac on blood pressure, renal function, and vasoactive prostanoids in young and elderly subjects

Cyclooxygenase (COX) inhibitors are among the most widely used drugs, especially in the elderly. It has been claimed that the new COX-2 inhibitors offer advantages in terms of drug safety. To test this hypothesis, the authors compared in a double-blind, randomized trial the effects of celecoxib (200 mg bid) and diclofenac (75 mg bid) on blood pressure and renal function in two groups (each n = 12) of young (mean age = 32 years) and elderly (mean age = 68 years) normotensive subjects. Changes from baseline in the 24-hour blood pressure profiles, parameters of the renin-angiotensin-aldosterone system, inulin clearance, urinary marker proteins, and eicosanoid excretion were monitored during the treatment period of 2 weeks. Comparison between celecoxib and diclofenac showed no significant difference in minor alterations of blood pressure. During daytime, there was a trend to elevation of mean arterial blood pressure (mmHg) by celecoxib in the elderly of 2.8 (95 % confidence interval [CI) = -2.5 to 8.2) in comparison with the young subjects of -1.3 (95% CI= -3.7 to 1.0); there was also a trend to elevation of mean arterial blood pressure by diclofenac in the elderly of 4.1 (95% CI= -1.2 to 9.4) in comparison with the young subjects of 0.4 (95% CI= -2.4 to 3.2). In both populations, the authors found no significant drug effects on the parameters of the renin-angiotensin-aldosterone system, inulin clearance, and urinary marker proteins. As expected, diclofenac reduced excretion of allprostanoids, whereas celecoxib did not affect production of TxB2 and its metabolites. Neither in young nor in elderly normotensive subjects were blood pressure and renal function significantly affected by a short-term treatment with standard doses of celecoxib and diclofenac. Therefore, normal aging appears not to represent a special risk factor in therapy with these two agents.

Effect of lysine clonixinate on the pharmacokinetics and anticoagulant activity of phenprocoumon

The effect of the non-steroidal anti-inflammatory drug lysine clonixinate ([2-(3-chloro-o-toluidino)nicotinic acid]-L-lysinate, CAS 55837-30-4) on the pharmacokinetics and anticoagulant activity of phenprocoumon (4-hydroxy-3-(1-phenylpropyl)-coumarin, CAS 435-97-2) was investigated in an open, randomised, two-fold, cross-over study in 12 healthy male volunteers. These subjects received a single dose of 18 mg phenprocoumon without or with concomitant treatment with lysine clonixinate (125 mg five times a day for 3 days before and 13 days after ingestion of a single dose of phenprocoumon). Pharmacokinetic parameters of phenprocoumon following oral administration were: CL/f: 0.779 +/- 0.157 ml/min, half-life of elimination: 147.2 +/- 19.9 h; free fraction in serum: 0.51 +/- 0.20%. These parameters were not significantly altered by concomitant treatment with lysine clonixinate. Prothrombin time increased from 13.3 +/- 1.3 s (at time 0) to 17.7 +/- 2.7 s following phenprocoumon and from 13.3 +/- 1.2 s to 18.0 +/- 2.2 s following combined administration. Prothrombin time returned to the pretreatment values 240 h after administration of phenprocoumon. The integrated effect (AUEC0-288 h) was identical following both treatments (4.303 +/- 461 and 4.303 +/- 312 s x h for phenprocoumon alone and phenprocoumon with lysine clonixinate, respectively). Thus, lysine clonixinate administered in therapeutic doses does not affect the pharmacokinetics and anticoagulant activity of phenproxoumon.

Determination of propafenone and its phase I and phase II metabolites in plasma and urine by high-performance liquid chromatography-electrospray ionization mass spectrometry

A sensitive method was developed to determine propafenone, 5-hydroxypropafenone, N-despropylpropafenone and propafenone glucuronides in human plasma and urine by HPLC-electrospray ionization mass spectrometry with the respective deuterated analogues as internal standards. The analytes were extracted by a single solid-phase extraction, collecting two fractions, one containing the glucuronides and the other propafenone and the phase I metabolites 5-hydroxypropafenone and N-despropylpropafenone. The mobile phases used for HPLC were: (A) 5 mM ammonium acetate in water and (B) 5 mM ammonium acetate in methanol-tetrahydrofuran (50:50, v/v). Separation of the diastereoisomeric propafenone glucuronides was achieved on a Spherisorb ODS 2 column (150 x 2.0 mm I.D., particle size 5 microm) at a flow-rate of 0.3 ml/min using a linear gradient from 20% B to 50% B in 15 min. For separation of propafenone, 5-hydroxypropafenone and N-desalkylpropafenone a linear gradient from 50% B to 80% B in 10 min was employed. The mass spectrometer was operated in the selected ion monitoring mode using the respective MH+ ions for quantification. The limits of quantification achieved with this method were 10 pmol/ml for propafenone, 5-hydroxypropafenone, R- and S-propafenone glucuronide and 20 pmol/ml for N-desalkylpropafenone using 0.5 ml of plasma. Reproducibility and accuracy was below 12% for each analyte over the whole concentration range measured. The method was applied to a pharmacokinetic study assessing the influence of rifampicin on propafenone disposition.

Disposition of propafenone in a poor metabolizer of CYP2D6 with Gilbert's syndrome

Gilbert's syndrome, a genetic deficiency in bilirubin UDP-glucuronosyltransferase (UGT1A1), may dispose to increased toxicity of propafenone in poor metabolizers (PMs) of cytochrome P4502D6 because glucuronidation of propafenone is the major metabolic pathway for drug elimination in PMs. A patient with Gilbert's syndrome who is also PM participated in an interaction study with propafenone and rifampicin along with five otherwise healthy PMs. Using stable isotope techniques, the pharmacokinetics of single doses of 140 mg propafenone i.v. (unlabelled) and 300 mg propafenone p.o. (labelled) were compared between the index patient and the five healthy controls. Propafenone did not accumulate in the plasma of the index patient either before or during induction: AUC(0-infinity) of propafenone in the index patient was within the 95% confidence interval of controls; AUC(0-infinity) of propafenone glucuronide and amount of urinary excretion of propafenone glucuronide in the patient were within or even greater than the 95% confidence intervals of controls. Therefore, individuals with Gilbert's syndrome who also have a PM phenotype appear to be at no higher risk for toxicity of propafenone than otherwise healthy PMs. An indirect conclusion from these in vivo data might be that propafenone is not a substrate of the UGT1A1 isoform.

Enzyme induction in the elderly: effect of rifampin on the pharmacokinetics and pharmacodynamics of propafenone

OBJECTIVE

A clinical study on enzyme induction in elderly subjects was performed by investigation of the effect of rifampin (INN, rifampicin) on propafenone disposition. Propafenone was chosen as a model drug because of its complex metabolism that permits the simultaneous in vivo assessment of induction of phase 1 and phase 2 pathways.

METHODS

Six extensive metabolizers of CYP2D6 (age, 70.5 +/- 3.5 years) ingested 600 mg rifampin once daily for 9 consecutive days. One day before the first rifampin dose and on the day of the last rifampin dose, each elderly individual received a single intravenous infusion of 70 mg unlabeled propafenone and received a single oral dose of 300 mg deuterated propafenone 2 hours later. Pharmacokinetics and pharmacodynamics of propafenone were compared before and during induction.

RESULTS

Maximum QRS prolongation after oral propafenone was decreased significantly by rifampin (18% +/- 5% versus 6% +/- 3%; P < .01). There were no substantial differences in pharmacokinetics and pharmacodynamics of intravenous propafenone during induction. However, bioavailability of propafenone dropped from 30% +/- 24% to 4% +/- 3% (P < .05). After oral propafenone was administered, clearances through N-dealkylation (6 +/- 3 mL/min versus 26 +/- 16 mL/min; P < .05) and glucuronidation (178 +/- 75 mL/min versus 739 +/- 533 mL/min; P < .05), but not 5-hydroxylation, were increased by rifampin, indicating substantial enzyme induction.

CONCLUSIONS

Both phase 1 and phase 2 pathways of propafenone metabolism were induced by rifampin in elderly subjects, resulting in a clinically relevant drug interaction.

Consequences of rifampicin treatment on propafenone disposition in extensive and poor metabolizers of CYP2D6

Propafenone undergoes extensive metabolism both by phase I and phase II enzymes: cytochrome P4502D6 (CYP2D6) dependent polymorphic hydroxylation to its main metabolite 5-OH-propafenone, CYP3A4/1A2 dependent N-dealkylation and further glucuronidation and sulfation. Since CYP2D6 is not inducible by rifampicin, an important drug interaction between rifampicin and propafenone is not to be expected a priori. However, non-CYP2D6-dependent pathways may be induced as a case report described dramatically lowered plasma concentrations of propafenone with loss of dysrhythmia control associated with rifampicin treatment. Therefore, this study aimed to investigate induction properties of rifampicin on propafenone disposition in extensive metabolizers and poor metabolizers of CYP2D6. Six extensive metabolizers and six poor metabolizers ingested 600 mg rifampicin once daily for nine consecutive days. The day before the first rifampicin dose and on the day of the last rifampicin dose each individual received a single intravenous (i.v.) infusion of 140 mg unlabelled propafenone and 2 h later a single dose of 300 mg deuterated propafenone orally (p.o.). During enzyme induction maximum QRS prolongation decreased significantly after propafenone p.o. (21 +/- 7% versus 13 +/- 6% in extensive metabolizers, P < 0.01; 15 +/- 6% versus 9 +/- 6% in poor metabolizers, P < 0.01) and not after propafenone i.v. In parallel, there were no substantial differences in pharmacokinetics of propafenone i.v. by rifampicin. However, bioavailability of propafenone dropped from 30 +/- 15% to 10 +/- 8% in extensive metabolizers (P < 0.01) and from 81 +/- 6% to 48 +/- 8% in poor metabolizers (P < 0.001). Following propafenone p.o. clearances through N-dealkylation (4.1 +/- 2.1 ml/min versus 23.5 +/- 12.6 ml/min in extensive metabolizers, P < 0.01; 3.4 +/- 1.3 ml/min versus 16.0 +/- 5.5 ml/min in poor metabolizers, P < 0.001) and glucuronidation (123 +/- 48 ml/min versus 457 +/- 267 ml/min in extensive metabolizers, P < 0.05; 43 +/- 9 ml/min versus 112 +/- 34 ml/min in poor metabolizers, P < 0.01), but not 5-hydroxylation increased regardless of phenotype indicating substantial enzyme induction. Clearances to propafenone sulfate and conjugates of 5-OH-propafenone were significantly enhanced by rifampicin treatment in poor metabolizers (P < 0.01). Thus, induction of both phase I pathways (CYP3A4/1A2) and phase II pathways (glucuronidation, sulfation) of propafenone by rifampicin resulted in a clinically relevant metabolic drug interaction which was more pronounced in extensive metabolizers than in poor metabolizers with regard to percentage decrease in bioavailability of propafenone.

Lack of drug interaction between omeprazole, lansoprazole, pantoprazole and theophylline

AIMS

Theophylline is a model substrate of cytochrome P4501A2. The ability of the proton pump inhibitors (PPI) omeprazole, lansoprazole and pantoprazole to induce cytochrome P4501A2 has not yet been unequivocally resolved. The aim of this comprehensive study was to compare directly the effect of the three PPI on the absorption and disposition of theophylline.

METHODS

Twenty healthy, nonsmoking, male and female volunteers (extensive metabolisers of cytochrome P4502C19 and Helicobacter pylori negative) participated in a randomized, double-blind, four-period, placebo-controlled crossover study. In each of the four periods they received either omeprazole (40 mg), lansoprazole (60 mg), pantoprazole (80 mg) or placebo once daily for 10 days. Sustained release theophylline (350 mg twice daily) was coadministered from day 8-10. Pharmacokinetics of theophylline as well as of all three PPI were determined at steady-state (day 10).

RESULTS

In all periods, point estimates and 90% confidence intervals of the area under the concentration-time curves (AUC), maximum steady-state concentrations and peak-trough fluctuations of theophylline were not altered by PPI pretreatment and met the required limits for bioequivalence. Point estimates (90% confidence intervals) of the AUC ratios of theophylline plus PPI to theophylline alone were 0.92 (0.87-0.97), 0.90 (0.85-0.95) and 1.00 (0.95-1.06) for omeprazole, lansoprazole and pantoprazole, respectively.

CONCLUSIONS

Concomitant intake of omeprazole, lansoprazole or pantoprazole at high therapeutic doses does not affect the absorption and disposition of theophylline.

Chronopharmacology of intravenous and oral modified release verapamil

AIMS

Using a stable isotope technique which allows simultaneous and differential measuring of orally and intravenously administered drugs we compared the pharmacokinetics and pharmacodynamics of unlabelled modified release verapamil p.o. (steady state) and deuterated verapamil i.v. (single dose) following morning and evening administration.

METHODS

Twelve female and 12 male healthy volunteers were studied in a randomized, crossover design. During the last day of each treatment period (day 6 and day 10) pharmacokinetics and pharmacodynamics (PR interval) of verapamil were assessed; 1 h before ingestion of a new R/S-verapamil 240 mg modified release formulation (08.00 h vs 20.00 h) a single dose of 10 mg d7-R/S-verapamil was administered intravenously. Serum levels of unlabelled and labelled R/S-verapamil were measured by gas chromatography/mass spectrometry. In selected samples of serum which were chosen at tmin,po and tmax,po the enantiomers were separated by chiral high-performance liquid chromatography in order to calculate R- to S-verapamil serum concentration ratios.

RESULTS

We observed no significant differences in pharmacokinetics (AUCpo, Cmax, tmax, CLo, F and R/S enantiomer ratio) between morning and evening treatment with modified release verapamil and there was no influence of time of dosing on mean prolongation of PR interval. AUCiv, CL, Vss and d7-R/d7-S enantiomer ratio following verapamil i.v. did not show circadian variation. t1/2 was slightly but statistically significantly increased after the morning infusion. PR-prolongation was significantly greater after verapamil i.v. in the morning than in the evening. The 90% confidence intervals of the differences between morning and evening administration in AUCpo, Cmax and AUCiv were within the equivalence range of 0.8-1.25.

CONCLUSIONS

Time of dosing has no significant influence on pharmacokinetics and pharmacodynamics of this new modified release formulation of verapamil. Circadian variation in presystemic metabolism of verapamil was not observed.

Pharmacokinetics and the pharmacodynamic action of midazolam in young and elderly patients undergoing tooth extraction

OBJECTIVE

To determine whether age-dependent pharmacokinetic and pharmacodynamic alterations account for a more pronounced response to benzodiazepines among elderly patients.

METHODS

Twelve young patients and 10 elderly patients received an intravenous dose of 0.05 or 0.03 mg/kg midazolan, respectively, before third molar extraction. Postoperative pain was treated with 30 mg dihydrocodeine. Serum concentrations of midazolam and sedative effects were monitored with visual analog scales and choice reaction time measurements for 6 hours. Test values above baseline were integrated, and pharmacokinetic-pharmacodynamic analysis was performed. Heart rate, blood pressure, arterial oxygen saturation, and amnesia also were assessed.

RESULTS

There were no significant age-dependent differences in disposition of midazolam between young and elderly patients (apparent volume of distribution, 1.3 +/- 0.2 versus 1.1 +/- 0.4 L/kg; halflife, 3.3 +/- 1.5 hours versus 3.7 +/- 2.2 hours; total body clearance, 451 +/- 186 ml/min versus 343 +/- 137 ml/min). However, higher values of area under the effect curve (AUEC) and AUEC divided by area under the serum concentration-time curve (AUC) (sensitivity index) were observed among the elderly as follows: AUEC for reaction time (AUECRT) (573 versus 261; p = 0.042), AUEC for visual analog scale (AUECVAS) (37.7 versus 14.4; p = 0.011), AUECRT/AUC (6.3 versus 1.8; p = 0.007), and AUECVAS/AUC (0.40 versus 0.11; p = 0.009) compared with the young group. Likewise, mean concentration at half-maximal effect for sedation was lower (p = 0.025) among older patients (20.5 +/- 2.2 ng/ml) than among younger (29.7 +/- 6.6 ng/ml) patients. Amnesia was observed among 86% of patients and oxygen saturation was always 95% or more of basal value. There were no age-related differences in concentration of dihydrocodeine and its active metabolite dihydromorphine, but dihydromorphone levels were much lower in there intermediate metabolizers (455 to 879 fmol/l) and especially in five poor metabolizers (65 to 498 fmol/L) than among extensive metabolizer of cytochrome p450 2D6 (1604 to 6490 fmol/L).

CONCLUSION

Elderly patients are more sensitive to the sedative action of midazolam than young patients, and the sensitivity is caused by age-dependent pharmacodynamic alterations. The age-adjusted doses used are both effective (for sedative amnesia) and safe (in terms of arterial oxygen saturation, heart rate, and blood pressure.

Gut wall metabolism of verapamil in older people: effects of rifampicin-mediated enzyme induction

AIMS

To investigate prehepatic metabolism of verapamil and its inducibility by rifampicin in older subjects.

METHODS

Eight older subjects (67.1 +/- 1.2 years mean +/- s.d.) received racemic, unlabelled verapamil orally for 16 days (120 mg twice daily). Rifampicin (600 mg daily) was coadministered from day 5 to 16. Using stable isotope technology (i.e. intravenous coadministration of 10 mg deuterated verapamil) during verapamil steady-state without (day 4) and with rifampicin (day 16) bioavailability, prehepatic and hepatic extraction of verapamil were determined. The effects of verapamil on AV-conduction were measured by the maximum PR interval prolongation (%).

RESULTS

Bioavailability of the cardiovascularly more active S-verapamil decreased from 14.2 +/- 4.3% on day 4 to 0.6 +/- 0.5% on day 16 (P < 0.001). As a consequence, effects of orally administered verapamil on the AV-conduction were nearly abolished (14.4 +/- 9.4% vs 2.7 +/- 2.6%, P < 0.01). This could be attributed to a considerable increase of prehepatic extraction during treatment with rifampicin (41.7 +/- 22.1% vs 91.6 +/- 6.6%, P < 0.01) and to a minor extent to induction of hepatic metabolism (73.7 +/- 9.4% vs 91.6 +/- 5.3%, P < 0.01).

CONCLUSIONS

Prehepatic metabolism of verapamil occurred in the group of older people investigated. Induction of gut wall metabolism most likely was the major reason for the loss of verapamil effect during treatment with rifampicin in this group of older subjects.