Trazodone Phenothiazines

The effects of buspirone are decreased when the drug is administered with fluoxetine Increased serum levels of buspirone occur if the drug is taken with erythromycin or itraconazole Should any of these combinations be required, the dosage of buspirone is decreased to 2.5 mg BID, and the patient is monitored closely. Venlafaxine blood levels increase with a risk of toxicity when administered witii MAOIs or cimetidine There is an increased risk of toxicity when trazodone is administered with the phenothiazines and decreased effectiveness of trazodone when it is administered with carbamazepine Increased serum digoxin levels have occurred when digoxin is administered with trazodone There is a risk for increased phenytoin levels when phenytoin is administered witii trazodone... 

Drugs that may affect trazodone include carbamazepine, phenothiazines, and venlafaxine. Drugs that may be affected by trazodone include alcohol, barbiturates, CNS depressants, digoxin, MAOIs, phenytoin, and warfarin. 

Acute alcohol intake, amiodarone, chloramphenicol, chlordiazepoxide, diazepam,dicumarofdisulfiram,estrogens, H -antagonists, halothane, isoniazid, methylphenidate, phenothiazines, phenylbutazone, salicylates, succinimides, sulfonamides, tolbutamide, trazodone... 

Asayesh K. Combination of trazodone and phenothiazines a possible additive hypotensive effect. Can J Psychiatry 1986 31(9) 857—8. 

A study, undertaken to confirm the involvement of the cytochrome P450 isoenzyme CYT2D6 in the metabolism of trazodone, found that when 11 depressed patients were given trazodone 150 to 300 mg at bedtime for 18 weeks, and then with thioridazine 20 mg twice daily for one week, the plasma levels of the trazodone and its active metabolite, /w-chlorophenyl-piperazine, rose by 36% and 54%, respectively. No adverse reactions were described. In contrast, a case of fatal hepatic necrosis with cholestasis has been attributed to the concurrent use of trazodone and phenothiazines. A 72-year-old woman taking trifluoperazine, trazodone and lithium carbonate developed an elevated alanine aminotransferase level. Trifluoperazine was replaced with thioridazine, but 9 weeks later she became jaundiced and developed hepatic encephalopathy, and died 6 weeks after the onset of jaundice. The authors consider that the combination of the phenothiazines and trazodone were the cause of her hepatic necrosis both phenothiazines and trazodone have been reported to individually cause hepatic adverse effects. ... 

Patients given phenothiazines and trazodone should be monitored for signs of excessive hypotension and should have their liver function tests closely monitored. 

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