Recent reports suggest that calcium channel blockers are harmful in the treatment of acute hypertension in adults. However, short-acting nifedipine is an effective and useful medication in pediatric hypertension and is currently utilized for hypertensive emergencies. This study will address these safety concerns in hypertensive children. Medical records (from five Canadian pediatric hospitals) of all pediatric hypertensive hospitalized children who were treated with short-acting nifedipine from January 1995 to December 1998 were retrospectively reviewed for patient demographics, dosing regimen, use of concomitant medications, co-morbid conditions, and presence/absence of minor and serious adverse events. Final data were extracted from 182 patients. Each patient had an average of 2.6 episodes of hypertension in hospital that required treatment, totaling 477 episodes. Within the 477 episodes, 1,162 doses of short-acting nifedipine were administered. The mean dose was 0.22 mg/kg (range 0.043-0.67 mg/kg, median 0.19 mg/kg) with 55.6% (260/468 episodes) receiving the drug via the sublingual route. Hypertension resolved in 85.5% (408/477) of the episodes. There were only 29 of 574 (5.1%) minor adverse events that were definitely or probably related to short-acting nifedipine administration. Two patients experienced a serious adverse event that involved of a reduction in blood pressure of more than 40%, but neither had any symptomatology from the serious adverse event and recovered spontaneously within 2 h. Short-acting nifedipine in hypertensive, hospitalized children appears to be a safe and efficacious medication with minimal side effects.