Fixed Combination Trandolapril/Verapamil Sustained-Release

In well designed studies in patients with mild to moderate hypertension, combinations of the sustained-release (SR) formulation of the nondihydropyridine calcium channel antagonist verapamil 120 to 240 mg/day and the ACE inhibitor trandolapril 0.5 to 8 mg/day were significantly more effective in reducing sitting systolic blood pressure (SBP) and diastolic blood pressure (DBP) from baseline than placebo. In most randomised studies, combinations of verapamil SR 120 to 240 mg/day and trandolapril 0.5 to 8 mg/day were significantly more effective in lowering sitting DBP and SBP than the corresponding monotherapies administered at the same dosage. Trandolapril/verapamil SR 2/180 mg/day provided significantly more effective 24-hour ambulatory blood pressure (BP) control than of the corresponding monotherapies. Moreover, trandolapril/verapamil SR reduced BP in patients inadequately controlled with either of the corresponding monotherapies.

The antihypertensive efficacy of trandolapril/verapamil SR 2/180 mg/day was generally similar to that of other combinations of antihypertensive agents (metoprolol/hydrochlorothiazide, atenolol/chlorthalidone, lisinopril/hydrochlorothiazide, enalapril/hydrochlorothiazide) in patients with hypertension, including those with type 2 diabetes mellitus.

Trandolapril/verapamil SR reduced BP in patients with hypertension and type 2 diabetes or primary renal disease, Black patients and elderly patients. Trandolapril/verapamil SR was more effective than the individual components administered as monotherapy in reducing proteinuria in patients with type 2 diabetes or primary renal disease. Trandolapril/verapamil SR had a neutral or beneficial effect on metabolic parameters (glucose, insulin, lipids) in patients with hypertension, including those with type 2 diabetes.

Trandolapril/verapamil SR preserved left ventricular function in patients with heart failure. Fewer cardiac events occurred after therapy with trandolapril/verapamil SR than after trandolapril alone in post-myocardial infarction patients with congestive heart failure.

The incidence of adverse events in recipients of trandolapril/verapamil SR was similar to that of the individual components, and that of other combination therapies. In placebo-controlled trials conducted in the US, headache, upper respiratory tract infections, cough, constipation, atrioventricular block (first degree) and dizziness were the most commonly reported adverse events in recipients of combinations of verapamil SR (120 to 240 mg/day) and trandolapril (0.5 to 8 mg/day).

Verapamil is a nondihydropyridine calcium channel antagonist that reduces blood pressure via the inhibition of the inward flow of calcium ions through the L-type channels. Verapamil appears to exert its antihypertensive effects without activating any counter-balancing mechanisms such as tachycardia, water or sodium retention or the stimulation of the renin-angiotensin-aldosterone system.

Trandolapril exerts its antihypertensive effects through inhibition of ACE. The decrease in angiotensin II levels leads to decreased vasopressor activity and decreased aldosterone secretion. Trandolapril also reduces the breakdown of bradykinin (a vasodilator).

The combination of trandolapril/verapamil sustained-release (SR) generally had no effect on heart rate in patients with hypertension; although a small, but significant, reduction in heart rate was reported in a randomised, double-blind study. In patients with hypertension, trandolapril/verapamil SR had a positive effect on aortic elastic properties (assessed according to pulse wave velocity) and decreased left ventricular (LV) mass. Trandolapril/verapamil SR improved LV ejection fraction in patients with angina pectoris (noncomparative study) and in patients with heart failure (comparative study). Fewer cardiac events occurred after trandolapril/verapamil SR than after monotherapy with trandolapril in post-myocardial infarction patients with congestive heart failure.

Trandolapril/verapamil SR had a neutral or beneficial effect on metabolic parameters (glucose, insulin, lipids) in patients with hypertension with or without type 2 diabetes mellitus. Trandolapril/verapamil SR reduced proteinuria in patients with hypertension and diabetic nephropathy and in patients with primary renal disease.

In volunteers administered a single dose of trandolapril/verapamil SR (dose not stated), peak plasma concentrations (C_max) values of verapamil, trandolapril and trandolaprilat were reached after 4 to 15, 0.5 to 2 and 2 to 12 hours, respectively.

The pharmacokinetics of trandolapril and trandolaprilat were the same when trandolapril was administered as monotherapy or as a fixed combination with verapamil SR. The verapamil area under the concentration-time curve (AUC) and Cmax increased by 65 and 54% when verapamil SR 240mg was administered in combination with trandolapril 4mg.

Trandolapril is rapidly converted in the liver to trandolaprilat, the biologically active diacid. The bioavailability of trandolapril is about 10% and that of trandolaprilat is about 70%. The bioavailability of trandolapril was not affected by the presence of food. The bioavailability of verapamil is low (10 to 20%), because of the rapid biotransformation of verapamil during hepatic first-past metabolism.

Plasma protein binding of verapamil is about 90%; that of trandolapril is about 80% and is independent of drug concentration. Trandolaprilat is highly bound to plasma protein in a concentration-dependent manner (94% at 0.04 μg/L).

Plasma concentrations of verapamil and trandolaprilat at steady-state (reached after approximately 1 week of once-daily trandolapril/verapamil SR) were up to 2-fold higher than those obtained with a single dose of trandolapril/verapamil SR.

The bioavailability and the time to C_max of verapamil were decreased by the presence of food. The bioavailabilities of verapamil and trandolapril were increased in elderly patients, relative to younger patients, administered trandolapril/ verapamil SR.

Approximately 70% of verapamil is excreted as metabolites in the urine, and 15% in the faeces. After administration of a radioactive dose of trandolapril, approximately 33% of the radioactivity was recovered in the urine and 66% in the faeces. Elimination of trandolaprilat is triphasic, with an effective elimination half-life of about 10 hours and a prolonged terminal elimination half-life.

In patients with hypertension administered trandolapril/verapamil SR, the presence of fatty liver disease did not alter the pharmacokinetics of verapamil. However, trandolaprilat C_max and AUC_24h values were elevated.

The pharmacokinetics of trandolapril were unchanged in patients with renal impairment; however, renal trandolaprilat clearance decreased with increasing renal insufficiency.

In randomised, double-blind studies, combination therapy with once-daily trandolapril 0.5 to 8mg and once-daily verapamil SR 120 to 240mg was significantly more effective in lowering sitting systolic blood pressure (SBP) and diastolic blood pressure (DBP) than placebo in patients with mild to moderate hypertension. The number of responders to treatment with trandolapril/verapamil SR 2/180, 2/240 and 4/240 mg/day was significantly higher than that with placebo. In most randomised studies, combinations of trandolapril 1 to 4 mg/day and verapamil SR 120 to 240 mg/day were significantly more effective in lowering sitting DBP and SBP than the corresponding monotherapies administered at the same dosage. The mean reduction in 24-hour ambulatory blood pressure (BP) was significantly greater with combination trandolapril/verapamil SR 2/180 mg/day than with either of the monotherapies administered at the same dosage. Moreover, trandolapril/verapamil SR was effective in reducing BP in patients unresponsive to either of the agents administered as monotherapy.

Trandolapril/verapamil SR was effective in reducing BP in special populations of patients with hypertension, including those with type 2 diabetes or primary renal disease, and black or elderly patients.

Reductions in BP were generally similar in recipients of trandolapril/verapamil SR 2/180 mg/day to those in recipients of other antihypertensive combinations (metoprolol/hydrochlorothiazide, atenolol/chlorthalidone, lisinopril/ hydrochlorothiazide, enalapril/hydrochlorothiazide) in patients with hypertension, including those with type 2 diabetes.

Trandolapril/verapamil SR is generally well tolerated and the adverse event profile corresponds to that of the monocomponents. In placebo-controlled trials, the incidence of adverse events was 28, 34, 27 and 26% in recipients of trandolapril/ verapamil SR 2/180 mg/day, trandolapril 0.5 to 8 mg/day, verapamil SR 120 to 240 mg/day and placebo, respectively. In placebo-controlled trials conducted in the US, headache, upper respiratory tract infections, cough, constipation, atrioventricular block (first degree) and dizziness were the most commonly reported adverse events in recipients of combinations of trandolapril (0.5 to 8 mg/day) and verapamil SR (120 to 240 mg/day). The incidence of prolongation of the PQ terval was similar in recipients of trandolapril/verapamil SR, the monotherapy components or placebo.

There were no significant differences in the incidence of adverse events in recipients of trandolapril/verapamil SR (34%), atenolol/chlorthalidone (32%), lisinopril/hydrochlorothiazide (29%), or placebo (21%) during a well designed, trial in patients with hypertension.

In the US, the fixed combination of trandolapril/verapamil SR is approved for the treatment of hypertension, but not for initial therapy. The recommended usual dosage of verapamil SR is 120 to 480 mg/day administered as a single dose or as two divided doses. The recommended usual dosage of trandolapril is 1 to 4 mg/day administered as a single dose or as two divided doses. Clinical trials of trandolapril/verapamil SR have only investigated once-daily dosing. The fixed combination of trandolapril/verapamil SR is available as 2/180, 1/240, 2/240 and 4/240mg tablets.

In European countries, the fixed combination of trandolapril/verapamil SR is available as 2/180mg capsules. The usual dosage is one capsule, taken once-daily in the morning.

Trandolapril/verapamil SR should be administered with food.

The safety and efficacy of trandolapril/verapamil SR has not been established in patients aged under 18 years. Trandolapril/verapamil SR is contraindicated in patients who are hypersensitive to an ACE inhibitor or verapamil. Trandolapril/ verapamil SR is also contraindicated in patients with severe LV dysfunction, hypotension (SBP <90mm Hg) or cardiogenic shock, in patients with sick sinus syndrome (except those with an artificial ventricular pacemaker), second or third degree atrioventricular block (except those with an artificial ventricular pacemaker), in patients with atrial flutter or atrial fibrillations and an accessory bypass tract, and in patients with a history of ACE inhibitor-related angioedema. Trandolapril/verapamil SR should be administered with caution to patients with renal or hepatic impairment.