Respiratory depression and apnea induced by propofol in dogs.

OBJECTIVE

To determine the maximal i.v. administered dose of propofol that would not induce a serious adverse event in nonsedated dogs.

ANIMALS

6 clinically normal dogs (3 males and 3 females) between 8 and 12 months old and weighing between 8.8 and 11.3 kg.

PROCEDURE

Propofol was administered i.v. at an initial dosage of 6.5 mg/kg of body weight at a rate of 20 mg/10 s. Subsequent doses were incrementally increased by 2.5 mg/kg (eg, second dose: 9 mg/kg) and separated by a minimum of 3 days. This procedure was repeated until a dose that induced a serious respiratory, cardiovascular, or neurologic adverse effect was determined.

RESULTS

Apnea was determined to be the serious adverse effect for all dogs. Duration of apnea varied between dogs, but increased in a dose-dependent manner at dosages > 14 mg/kg.

CONCLUSIONS

Respiratory depression and apnea are the most likely adverse effects induced by i.v. administration of propofol to dogs. Propofol administered i.v. at a rate of 20 mg/kg/10 s induces minimal cardiovascular depression at dosages in excess of the apneic dosage.

CLINICAL RELEVANCE

Respiratory depression and apnea should be expected as potential adverse effects after i.v. administration of propofol to dogs, particularly when administered at rapid rates of infusion.