guanadrel and methylphenidate (Moderate Drug-Drug)
MONITOR: Central nervous system (CNS) stimulants, particularly the amphetamines, may decrease the hypotensive effect of postganglionic adrenergic blocking agents such as guanadrel, guanethidine and rauwolfia alkaloids, which work by depleting catecholamine stores from adrenergic nerve endings. CNS stimulants can have peripheral sympathetic activity, thus they may elevate blood pressure on their own as well as antagonize some of the antiadrenergic effect produced by these hypotensive agents. Amphetamines reportedly also may displace the blocking agent, guanethidine, and inhibit its uptake by adrenergic neurons. Other mechanisms have also been proposed. In addition to diminished hypotensive response, the interaction has also been reported to produce hypotension and ventricular tachycardia in a patient stabilized on guanethidine shortly after initiating treatment with methylphenidate.
MANAGEMENT: Alternatives to postganglionic adrenergic blocking agents should be considered in hypertensive patients treated with CNS stimulants. If the combination is used, blood pressure and heart rate should be monitored.
guanadrel and methylphenidate (Moderate Drug-Drug)
