THE EFFECT OF PENTAZOCINE ON PUPILLARY SIZE AND INTRACRANIAL PRESSURE

Abstract

SUMMARY The effect of pentazocine 40 mg on pupillary size and reaction was investigated and compared with morphine 15 mg in 20 conscious patients. Pentazocine produced less pupilary constriction and the pupillary reaction to light was preserved. The effect of pentazocine on intracranial pressure was studied in 8 anaesthetized ventilated patients. Pentazocine was found to cause a small fall in intracranial pressure despite the fact that blood pressure and Paoo3 were unaltered. The effect of pentazocine on intracranial pressure was studied in 11 spontaneously breathing patients with brain damage. Pentazocine caused an increase in intracranial pressure in 9 patients which was probably due to a rise in Paoo2. The increase was least when the initial level of intracranial pressure was low. Pentazocine, therefore, may have a place in the relief of pain in head injuries. Measurements of respiratory depression and ventricular fluid pressure after administration, however, suggest that caution be excercised and the drug may best be used in small intravenous doses.