Drug Interactions between morphine liposomal and Urolene Blue

CONTRAINDICATED: Monoamine oxidase inhibitors (MAOIs) markedly potentiate the action of morphine. Coadministration of narcotic analgesics including morphine in patients treated with MAOIs has rarely resulted in hypotension, respiratory depression, or coma. There appear to be two types of interaction, an excitatory and a depressive one. Symptoms of the excitatory reaction may include agitation, headache, diaphoresis, hyperpyrexia, flushing, shivering, myoclonus, rigidity, tremor, diarrhea, hypertension, tachycardia, seizures, and coma. Death has occurred in some cases. The exact mechanism of interaction is unknown, but may involve excessive serotonergic activity in the central nervous system (i.e., serotonin syndrome). The interaction is unpredictable and has been reported primarily with meperidine or fentanyl and various MAOIs including phenelzine, tranylcypromine, linezolid, moclobemide, and selegiline. Fatal hyperpyrexia and hypertension have also been observed in animal studies with meperidine and phenelzine or furazolidone. In contrast, symptoms of the depressive reaction probably stem from potentiation of CNS effects by MAOIs and include respiratory depression, cyanosis, hypotension, and coma. The interaction is also expected to occur with diamorphine.

MANAGEMENT: The use of morphine including liposomal formulations or diamorphine with MAOIs or other agents which possess MAOI activity (e.g., furazolidone, procarbazine, selegiline), together or within 14 days of stopping a MAOI is considered contraindicated.