Drug Interactions between amitriptyline / perphenazine and esketamine

MONITOR CLOSELY: Concomitant use of esketamine with central nervous system (CNS) depressants may increase sedation and impairment of attention, judgment, thinking, reaction speed, and psychomotor skills. In clinical trials, 49% to 61% of esketamine-treated patients developed sedation based on the Modified Observer's Alertness/Sedation scale (MOAA/s), and 0.3% of esketamine-treated patients experienced loss of consciousness (MOAA/s score of 0). In the MOAA/s scale, 5 means "responds readily to name spoken in normal tone" and 0 means "no response after painful trapezius squeeze," and any decrease in MOAA/s from pre-dosing of esketamine is considered to indicate presence of sedation. Dose-related increases in the incidence of sedation were also observed in a fixed-dose study. Additionally, cognitive performance decline was reported in a study in healthy volunteers who received a single intranasal dose of esketamine. Compared to placebo-treated subjects, esketamine-treated subjects required a greater effort to complete cognitive tests at 40 minutes post-dose, although results were comparable between the two groups at 2 hours post-dose. Drowsiness was comparable after 4 hours post-dose.

MANAGEMENT: Caution is advised and patients should be closely monitored during concomitant use of esketamine with CNS depressants or other drugs that can cause sedation or dizziness. Due to the risk of delayed or prolonged sedation and other adverse effects, patients should be monitored for at least 2 hours after esketamine administration, followed by an assessment to determine when the patient is considered clinically stable and ready to leave the healthcare setting. Patients should be instructed not to engage in potentially hazardous activities that require complete mental alertness and motor coordination, such as driving a motor vehicle or operating machinery, until the next day after a restful sleep.

MONITOR CLOSELY: Concomitant use of esketamine with central nervous system (CNS) depressants may increase sedation and impairment of attention, judgment, thinking, reaction speed, and psychomotor skills. In clinical trials, 49% to 61% of esketamine-treated patients developed sedation based on the Modified Observer's Alertness/Sedation scale (MOAA/s), and 0.3% of esketamine-treated patients experienced loss of consciousness (MOAA/s score of 0). In the MOAA/s scale, 5 means "responds readily to name spoken in normal tone" and 0 means "no response after painful trapezius squeeze," and any decrease in MOAA/s from pre-dosing of esketamine is considered to indicate presence of sedation. Dose-related increases in the incidence of sedation were also observed in a fixed-dose study. Additionally, cognitive performance decline was reported in a study in healthy volunteers who received a single intranasal dose of esketamine. Compared to placebo-treated subjects, esketamine-treated subjects required a greater effort to complete cognitive tests at 40 minutes post-dose, although results were comparable between the two groups at 2 hours post-dose. Drowsiness was comparable after 4 hours post-dose.

MANAGEMENT: Caution is advised and patients should be closely monitored during concomitant use of esketamine with CNS depressants or other drugs that can cause sedation or dizziness. Due to the risk of delayed or prolonged sedation and other adverse effects, patients should be monitored for at least 2 hours after esketamine administration, followed by an assessment to determine when the patient is considered clinically stable and ready to leave the healthcare setting. Patients should be instructed not to engage in potentially hazardous activities that require complete mental alertness and motor coordination, such as driving a motor vehicle or operating machinery, until the next day after a restful sleep.

MONITOR: Coadministration of a phenothiazine with a tricyclic antidepressant (TCA) may result in elevated plasma concentrations of one or both drugs as well as additive adverse effects. Most phenothiazines and TCAs have been found to undergo metabolism by CYP450 2D6, thus competitive inhibition of the enzyme may occur when more than one of these agents are administered. Although these drugs have been used together clinically, the possibility of increased risk of serious adverse effects such as central nervous system depression, tardive dyskinesia, hypotension, and prolongation of the QT interval should be considered, as many of these agents alone can and have produced these effects. In addition, excessive anticholinergic effects may occur in combination use, which can result in paralytic ileus, hyperthermia, heat stroke, and the anticholinergic intoxication syndrome. Peripheral symptoms of anticholinergic intoxication commonly include mydriasis, blurred vision, flushed face, fever, dry skin and mucous membranes, tachycardia, urinary retention, and constipation. Central symptoms may include memory loss, disorientation, incoherence, hallucinations, psychosis, delirium, hyperactivity, twitching or jerking movements, stereotypy, and seizures.

MANAGEMENT: Concurrent use of phenothiazines and TCAs should be approached with caution, particularly in the elderly and those with underlying organic brain disease, who tend to be more sensitive to the central anticholinergic effects of these drugs and in whom toxicity symptoms may be easily overlooked. Patients should be advised to notify their physician promptly if they experience potential symptoms of anticholinergic intoxication (e.g., abdominal pain, fever, heat intolerance, blurred vision, confusion, hallucinations) or cardiovascular toxicity (e.g., dizziness, palpitations, arrhythmias, syncope). Ambulatory patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them. A dosage reduction in one or both drugs may be necessary if excessive adverse effects develop.