a. Administration of drugs. Aircrew members taking drugs which have a systemic effect will be restricted from flying duties until convalescence and/or rehabilitation is completed. This will not, however, be construed as prohibiting aircrew members use of chemoprophylactic agents recommended after aeromedical evaluation by the appropriate medical authority. All drugs and medications will be dispensed by or with the knowledge of a flight surgeon. Individuals receiving the following drugs or types of drugs will be restricted from flying duties as indicated:
(1) Alcohol--12 hours after last drink consumed and until no residual effects remain.
(2) Antihistamines or barbiturates--for the period taken and for 24 hours after discontinued or after any sequelae, whichever is longer.
(3) Mood ameliorating, tranquilizing, or ataraxic drugs--for the period
they are used and for 4 weeks after the drug has been discontinued. When
medications are utilized for nonpsychotropic reasons, such as for
symptomatic relief of vomiting or muscle spasm, the period of disability
will last only for the duration of the acute illness and for 72 hours
after cessation of medication.