Drug Interactions between deserpidine and Duo-Medihaler

MONITOR: Coadministration of beta-2 adrenergic agonists with other adrenergic agents may potentiate the risk of cardiovascular side effects. Beta-2 adrenergic agonists can produce clinically significant cardiovascular effects including increases in pulse rate and systolic or diastolic blood pressure as well as ECG changes such as flattening of the T wave, prolongation of the QTc interval, and ST segment depression. The risk is lower when beta-2 adrenergic agonists are inhaled at normally recommended dosages. However, these effects may be more common when the drugs are administered systemically or when recommended dosages are exceeded.

MANAGEMENT: Caution is advised if beta-2 adrenergic agonists are used concomitantly with other adrenergic agents, particularly in patients with cardiovascular disorders such as coronary insufficiency, cardiac arrhythmias, hypertrophic obstructive cardiomyopathy, or hypertension. Blood pressure and heart rate should be closely monitored.

MONITOR: Postganglionic adrenergic blocking agents may potentiate the pharmacologic effects of direct-acting sympathomimetic amines, while the hypotensive effect of the former may be diminished. Postganglionic adrenergic blocking agents such as guanadrel, guanethidine, and rauwolfia alkaloids work by depleting catecholamine stores from adrenergic nerve endings, thus they may sensitize adrenergic receptors to direct-acting sympathomimetics. Clinically, hypertension and other cardiovascular adverse effects may occur.

MANAGEMENT: Due to their pressor effect, sympathomimetic amines should be used cautiously in patients with hypertension. Conversely, alternatives to postganglionic adrenergic blocking agents should be considered in patients treated with sympathomimetic amines. If the combination is used, blood pressure and heart rate should be closely monitored.

MONITOR: Sympathomimetic amines may decrease the hypotensive effect of postganglionic adrenergic blocking agents, while the latter may potentiate the pharmacologic effects of direct-acting sympathomimetic amines (e.g., dobutamine, epinephrine, methoxamine, norepinephrine) but inhibit those that are primarily indirect-acting (e.g., mephentermine). Postganglionic adrenergic blocking agents such as guanadrel, guanethidine, and rauwolfia alkaloids work by depleting catecholamine stores from adrenergic nerve endings. Therefore, they may sensitize adrenergic receptors to direct-acting sympathomimetics, but blunt the effects of indirect-acting agents whose activity is mediated through the release of catecholamines. Guanethidine and reserpine have been reported to attenuate the pharmacologic effects (mydriasis, pressor response) induced by ephedrine and dopamine, both of which exhibit direct and indirect sympathomimetic activities (i.e., mixed-acting). However, guanethidine intensified the mydriasis produced by phenylephrine, which is also thought to be mixed-acting. Conversely, ephedrine has been shown to partially reverse the hypotensive effect of guanethidine.

MANAGEMENT: Due to their pressor effect, sympathomimetic amines should be used cautiously in patients with hypertension. Alternatives to postganglionic adrenergic blocking agents should be considered if patients are treated with sympathomimetic amines, since effects of the latter may be intensified or diminished depending on whether they are direct- or indirect-acting. Most agents with indirect sympathomimetic activity are mixed-acting, thus it may be difficult to predict how they will be affected by postganglionic adrenergic blocking agents. If the combination is used, blood pressure and heart rate should be monitored.