Donepezil Risperidone

Geizer M, Ancill RJ Combination of risperidone and donepezil in Lewy body dementia. Can J Psychiatry 43 421-422, 1998... 

Friedman JI, Adler DN, Howanitz E, Harvey PD, Brenner G, et al. 2002. A double blind placebo controlled trial of donepezil adjunctive treatment to risperidone for the cognitive impairment of schizophrenia. Biol Psychiatry 349-357. 

A 74-year-old man with Lewy body dementia treated with a combination of donepezil (5 mg in the evening) and risperidone (0.25 mg/day) had significant improvement, objectively and subjectively, within 2 weeks. 

Possible interactions between donepezil and risperidone, which are both metabolized by CYP2D6 and CYP3A4, have been studied (SEDA-26,65) (247). Of 24 healthy men (mean age 40 years) were assigned to risperidone 1 mg/day, donepezil 5 mg/day, or both, 20 reported at least one adverse event, mostly headache, nervousness, or somnolence. However, measures of pharmacokinetics showed no interaction. 

Zhao Q, Xie C, Pesco-Koplowitz L, Jia X, Parier J-L. Pharmacokinetic and safety assessments of concurrent administration of risperidone and donepezil. J Clin Pharmacol 2003 43 180-6. 

An open comparison of donepezil and risperidone, alone or in combination, in 24 healthy men showed no significant pharmacokinetic differences (88). Adverse events such as headache, nervousness, and somnolence were minor and comparable in all groups. These results suggest that no clinically significant interactions occur between risperidone and donepezil at steady state. However, whether these conclusions can be extrapolated to the elderly patients with dementia, who may eliminate both donepezil and risperidone slowly, is uncertain. 

Magnuson TM, Keller BK, Burke WJ. Extrapyramidal side effects in a patient treated with risperidone plus donepezil. Am J Psychiatry 1998 155(10) 1458-9. 

A 76-year-old woman began taking an extract of St. John s wort (75 mg/day) and developed delirium and psychosis 3 weeks later (179). She had no relevant medical history and did not take any other medications. She was given risperidone and donepezil hydrochloride, and her paranoid delusions and visual hallucinations improved. 

IMATINIB 1. ANTIARRHYTHMICS -flecainide, mexiletine, propafenone 2. ANTIDEPRESSANTS - fluoxetine, paroxetine, TCAs, trazodone, venlafaxine 3. ANTIPSYCHOTICS -clozapine, haloperidol, perphenazine, risperidone, thioridazine 4. BETA-BLOCKERS - metoprolol, propanolol, timolol 5. DONEPEZIL 6. METHAMPHETAMINE Imatinib may cause t plasma concentrations of these drugs, with a risk of toxic effects Inhibition of CYP2D6-mediated metabolism of these drugs Watch for early features of toxicity of these drugs... 

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