Transient effect of nifedipine on pulmonary hypertension of systemic sclerosis.

A 64-year-old woman with systemic sclerosis and pulmonary hypertension underwent Swan-Ganz catheterization to test her response to the calcium channel blocker nifedipine. Pulmonary vascular resistance decreased from 2095 to 1333 dynes sec cm-5 with an initial dose of the drug. She developed tolerance to nifedipine within 12 h and subsequent doses had no effect on her pulmonary circulation. Our study confirms that acute administration of nifedipine reduces pulmonary vascular resistance in systemic sclerosis. However, an initial response to nifedipine does not predict benefit from continued administration of the drug.