Oral administration of diltiazem decreases ventilation and metabolism of Syrian hamsters.

1. Diltiazem at doses of 2.5, 25, and 50 mg/kg caused a reduction of minute ventilation of hamsters over a 60 min period compared to saline administration. 2. The decrease of ventilation was due to a fall in frequency of breathing, but predominantly due to a decrease of tidal volume. 3. The pattern of metabolic response of hamsters to diltiazem was different to the ventilatory response--but metabolic rate was decreased in all animals receiving diltiazem by 60 min compared to pregavage values.