Nifedipine in Raynaud's phenomenon: relationship between immediate, short term and longterm effects.

Sixteen patients with Raynaud's phenomenon (8 with primary Raynaud's, 8 with systemic sclerosis including 3 patients with CREST) were treated for 4 weeks in a double blind crossover study with nifedipine, 20 mg twice daily. Treatment resulted in improvement of symptoms (p less than 0.05), a lower frequency of attacks (p less than 0.05) and a tendency to a shorter duration of the attacks. Photoelectric plethysmography during nifedipine treatment showed greater amplitudes on cooling (p less than 0.05) and a better and faster recovery on rewarming (p less than 0.05) than during placebo. The immediate effect of nifedipine, 10 mg sublingually, on the amplitude of the plethysmogram, finger temperature, heart rate and blood pressure did not correlate with the effect of maintenance treatment. Dose titration based on therapeutic effect and side effects resulted in a dose of 20 mg daily for 5 patients, 40 mg for 7, and 80 mg daily for 3 patients. Longterm treatment (16-20 weeks) resulted in sustained efficacy, both by subjective and objective standards (plethysmography).