Donepezil Paroxetine

Two elderly patients with Alzheimer s disease and a mood disorder were treated with donepezil 5 mg/day and paroxetine 20 mg/day. One of them became agitated, confused, and aggressive, and donepezil was withdrawn after 8 days. On reintroduction of donepezil she again became rapidly confused, irritable, and verbally aggressive. In the other case, while the patient was taking paroxetine, donepezil 5 mg/day resulted in severe diarrhea, flatulence, and insomnia. The dosage of donepezil was reduced to 5 mg on alternate days, but the diarrhea and flatulence persisted. The symptoms resolved when donepezil was stopped. 

A possible interaction between donepezil and paroxetine has been described (86). 

Donepezil is metabolized in the liver by CYP2D6 and CYP3A4. Selective serotonin re-uptake inhibitors (SSRIs), such as paroxetine, are potent inhibitors of CYP2D6. Mood disorders are common in patients with Alzheimer s disease, and SSRIs are used in these patients and can increase the plasma concentration of donepezil, increasing the risk of severe adverse reactions. 

Carrier L. Donepezil and paroxetine possible drug interaction. J Am Geriatr Soc 1999 47(8) 1037. 

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... 

Fluvoxamine markedly increases the levels of tacrine, and increases its cholinei ic adverse effects, whereas fluoxetine, paroxetine, and sertraline are not expected to interact. Paroxetine and fluoxetine may increase donepezil and galantamine levels. Sertraline does not appear to have a pharmacokinetic interaction with donepezil, and concurrent use seems generally well tolerated however, one report describes hepatotoxicity, possibly as a result of their concurrent use. Rivastigmine and fluoxetine appear not to interact. 

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