Drug Interactions between levomethadyl acetate and Urolene Blue

GENERALLY AVOID: Coadministration of narcotic analgesics with monoamine oxidase inhibitors (MAOIs) has been associated with rare reports of anxiety, confusion, hypotension, respiratory depression, cyanosis, and coma. The mechanism of interaction is unknown, but may involve potentiation of central nervous system (CNS) and respiratory depressant effects by MAOIs. There have also been reports of serotonin syndrome, which is a rare but serious and potentially fatal condition thought to result from hyperstimulation of brainstem 5-HT1A and 2A receptors. Symptoms of the serotonin syndrome may include mental status changes such as irritability, altered consciousness, confusion, hallucination, and coma; autonomic dysfunction such as tachycardia, hyperthermia, diaphoresis, shivering, blood pressure lability, and mydriasis; neuromuscular abnormalities such as hyperreflexia, myoclonus, tremor, rigidity, and ataxia; and gastrointestinal symptoms such as abdominal cramping, nausea, vomiting, and diarrhea. Some opioids such as fentanyl, meperidine, methadone, tapentadol, and tramadol can inhibit serotonin reuptake. However, serotonin syndrome has also occurred with other opioids. Concomitant use of pentazocine with MAOIs may also cause CNS excitation and hypertension through their respective effects on catecholamines.

MANAGEMENT: Narcotic analgesics should generally not be used with MAOIs or other agents that possess MAOI activity (e.g., furazolidone, linezolid, methylene blue, procarbazine). At least 14 days should elapse between discontinuation of MAOI therapy and initiation of treatment with opioids.