Drug Interactions between amitriptyline / chlordiazepoxide and brimonidine topical

MONITOR: Central nervous system- and/or respiratory-depressant effects may be additively or synergistically increased in patients taking multiple drugs that cause these effects, especially in elderly or debilitated patients. Sedation and impairment of attention, judgment, thinking, and psychomotor skills may increase.

MANAGEMENT: During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. Cautious dosage titration may be required, particularly at treatment initiation. Ambulatory patients should be counseled to avoid hazardous activities requiring mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

MONITOR: Tricyclic and tetracyclic antidepressants can diminish the effects of centrally acting alpha agonists. The clinical significance, if any, of this interaction with respect to topically administered alpha-2 adrenergic receptor agonists such as brimonidine is unknown. The possibility of an additive or potentiating central nervous system (CNS)-depressant effect should be considered. Additive hypotensive effects and orthostasis may also occur, particularly during initial dosing of these agents.

MANAGEMENT: Patients receiving topical alpha-2 adrenergic receptor agonists in combination with tricyclic and tetracyclic antidepressants should be made aware of the potential for increased adverse effects such as drowsiness, dizziness, lightheadedness, confusion, hypotension and syncope, and counseled to avoid activities requiring mental alertness until they know how these agents affect them. Patients should also avoid rising abruptly from a sitting or recumbent position and notify their physician if they experience orthostasis or tachycardia. No data are available on the level of circulating catecholamines after withdrawal of a topical alpha-2 adrenergic receptor agonist. Since tricyclic antidepressants can affect the metabolism and uptake of circulating amines, caution is advised.

MONITOR: Topically administered alpha-2 adrenergic receptor agonists such as apraclonidine and brimonidine are systemically absorbed, with the potential for producing rare but clinically significant systemic effects. Although the interaction has not been specifically studied, the possibility of an additive or potentiating effect with central nervous system (CNS) depressants such as alcohol, barbiturates, opiates, anxiolytics, sedatives, and anesthetics should be considered. Additive hypotensive effects and orthostasis may also occur with some CNS depressants and other agents that have these effects, particularly during initial dosing and/or parenteral administration.

MANAGEMENT: Patients receiving topical alpha-2 adrenergic receptor agonists in combination with agents that can cause CNS depression should be made aware of the potential for increased adverse effects such as drowsiness, dizziness, lightheadedness and confusion, and counseled to avoid activities requiring mental alertness until they know how these agents affect them. Patients should also avoid rising abruptly from a sitting or recumbent position and notify their physician if they experience orthostasis or tachycardia.