Sibutramine Cimetidine

Drugs that may affect venlafaxine include cimetidine, cyproheptadine, and MAOIs. Drugs that may be affected by venlafaxine include clozapine, desipramine, haloperidol, indinavir, St. John s wort, trazodone, sibutramine, sumatriptan, and warfarin. 

Clinically important, potentially hazardous interactions with cimetidine, dihydroergotamine, ergot, fluoxetine, fluvoxamine, isocarboxazid, MAO inhibitors, methysergide, moclobemide, naratriptan, oral contraceptives, phenelzine, rizatriptan, sertraline, sibutramine, St John s wort, sumatriptan, tranylcypromine... 

On theoretical grounds the manufacturers contraindicate the concurrent use of sibutramine with MAOIs, and they say that it should not be given with serotonei ic drugs because of the risk of the serious serotonin syndrome. The manufacturers say that the use of sibutramine with other centrally acting appetite suppressants is contraindicated and they caution the use of cold and flu remedies. No clinically relevant interactions have been seen between sibutramine and cimetidine, and no interaction occurs with oral contraceptives. 

When cimetidine 400 mg twice daily was given with sibutramine 15 mg once daily to 12 healthy subjects the maximum serum levels and AUCs of the combined sibutramine metabolites were increased by 3.4% and 7.3%, respectively. These changes are too small to be of clinical significance, and there is no reason for avoiding the concurrent use of these two drugs. 

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