Side effects of antimotion sickness drugs.

The possible influence on operational proficiency of the side effects of the anti-motion sickness drugs was investigated using a computerized pursuit meter as the test device. The medications and doses tested were scopolamine (Hyoscine) 0.25 mg and 0.50 mg oral doses, promethazine (Phenergan) 25 mg oral and 25 mg I.M. doses. Combinations of promethazine 25 mg with 10 mg d-amphetamine (Dexadrine) oral were also used, as was a combination of promethazine 25 mg oral with promethazine 25 mg I.M. and 10 mg of oral d-amphetamine. The proficiency on the pursuit meter task was not significantly altered by 0.25 mg or 0.50 mg doses of scopolamine. The combination of promethazine 25 mg oral with 10 mg d-amphetamine did not produce a significant decrement of performance. When promethazine 25 mg was given as an oral or I.M. dose without amphetamine the decrement of performance was significant and was approximately equivalent to an alcohol blood level of 25-50 mg% (one-two drinks). When a combination of promethazine 25 mg oral plus promethazine 25 mg I.M. with 10 mg d-amphetamine was tested, the error scores were significantly lower than with the oral or I.M. dose of promethazine. This combination also produced an error score significantly higher than placebo level. Promethazine by the I.M. route was slowly absorbed and 6 of the 10 subjects reported drowsiness at 6 h post injection.