No abstract

1. The pharmacokinetics of a single oral dose of 20 mg nifedipine, given as capsules, has been compared in five South Asian volunteers with data for 27 Caucasian volunteers. 2. The area under the plasma concentration‐time curve (AUC) of nifedipine was three fold higher in South Asians (989 +/‐ 166 ng ml‐1 h) than in Caucasians (323 +/‐ 116 ng ml‐1 h). 3. The ratio of the AUC of nifedipine to that of the nitropyridine analogue, which is formed largely as a first pass metabolite, was significantly higher in South Asians (4.6 +/‐ 1.9) than in Caucasians (2.3 +/‐ 1.1) indicating a lower first pass metabolism in South Asians. 4. The terminal half‐lives of nifedipine and the nitropyridine metabolite were significantly greater in South Asians than in Caucasians. 5. Consumption of a spicy curry diet for 3 days by Caucasians did not significantly affect the pharmacokinetics of a single oral dose of nifedipine. 6. The treatment of patients of South Asian origin with nifedipine should be initiated with lower doses than would be given to Caucasians.

No abstract

1. The efficacy and acceptability of enalapril were assessed in a double‐blind, randomised, placebo controlled cross‐over study in 21 patients with primary Raynaud's phenomenon. 2. Skin temperature was assessed by thermocouples in response to a 15 degrees C cold water challenge as an index of digital blood flow. 3. Following enalapril there were no significant changes in the number and severity of Raynaud's attacks, and no subjective benefit from treatment as measured by visual analogue scales, 5 point rating scales, and skin temperature response to cold challenge when compared with placebo. 4. Enalapril in a dose of 20 mg daily is ineffective in the management of primary Raynaud's phenomenon.

1. The efficacy of verapamil alone, or in combination with digoxin, was compared with digoxin alone in eight patients with chronic atrial fibrillation in this double-blind placebo-controlled study. 2. After 2 weeks on each treatment regimen, heart rate at rest and during progressive load treadmill exercise, left ventricular function at rest and nocturnal heart rate were measured. 3. Oral verapamil alone at a dose of 80 mg three times daily, or 40 mg of verapamil three times daily in combination with 0.25 mg of digoxin daily, was superior to digoxin alone in doses associated with high serum digoxin concentrations (mean +/- SEM 1.6 +/- 0.3 micrograms/l). This superiority manifested as greater control of heart rate during work rates equivalent to regular daily activities, and was not associated with deterioration in left ventricular function or worsening nocturnal bradycardia. 4. We conclude that the treatment of choice in patients with chronic atrial fibrillation is either 80 mg of verapamil three times daily or 40 mg of verapamil three times daily in combination with digoxin.