Effects of low-dose nifedipine on a cold provocation test in patients with Raynaud's disease.

The effects of 5 mg sublingual nifedipine on a standardized cold provocation test were compared with that of placebo in a double-blind, cross-over trial in 10 patients with Raynaud's disease. The percentage decrease of finger systolic pressure in the cooled finger (as compared with the contralateral control finger) was significantly lower at 10 degrees C (p less than 0.02) and 15 degrees C (p less than 0.05) after nifedipine than after placebo. These improved digital pressure values on cooling were associated with a decreased systolic blood pressure (SBP) from 131.2 (SD 10.8) to 126.2 (SD 10.1) mm Hg (p less than 0.001) and an increased heart rate (HR) from 65.5 (SD 16.1) to 69.6 (SD 16.7) beats/min (p less than 0.002) but without significant changes in diastolic blood pressure (DBP), digital blood flow (BF), or peripheral vascular resistance (PVR) in cutaneous vascular bed. Three patients experienced headache under nifedipine, but this side effect was disagreeable in only one case. These data suggest using low-dose nifedipine (5 mg sublingually) 15-30 min before predictable cold exposure and Raynaud's phenomenon. Such a procedure might be more effective and safer than chronic intake of higher doses of nifedipine, as currently recommended in Raynaud's attacks.