Venlafaxine Haloperidol

HALOPERIDOL VENLAFAXINE t haloperidol levels Inhibited metabolism Avoid co-administration... 

CYP2D6 TCAs, SSRIs, haloperidol, mirtazepine, zuclopenthoxil, venlafaxine, sertraline CYP2C19 TCAs, mephenytoin, diazepam, moclobemid, venlafaxine... 

Antidepressants tricyclics, fluoxetine, paroxetine, sertraline, mirtazepine, venlafaxine, mianserin Antipsychotics phenothiazines, haloperidol, clozapine, olanzapine, quetiapine... 

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. 

P450 IID6 -fin women Inhibited by OCs Hydroxylation of nortriptyline and desipramine, haloperidol, clozapine, risperidone, venlafaxine Fluoxetine, fluvoxamine, paroxetine, sertraline... 

D6 Tricyclic antidepressants (TCAs), benztropine, perphenazine, clozapine, haloperidol, codeine/oxycodone, risperidone, class Ic antiarrhythmics, 3 blockers, trazodone, paroxetine, maprotiline, amoxapine, duloxetine, mirtazapine (partly), venlafaxine, bupropion Fluoxetine, paroxetine, duloxetine, hydroxybupropion, methadone, cimetidine, haloperidol, quinidine, ritonavir Phenobarbital, rifampin... 

During the course of a study of the salts formed by saccharin with quinine, haloperidol, mirtazapine, pseudoephedrine, lamivudine, risperidone, sertraline, venlafaxine, zolpidem, and amlodipine, a 1 1 cocrystal of saccharin and piroxicam was detected [68]. In the crystal structure, the asymmetric unit was found to consist of one saccharin molecule and one zwitterionic piroxicam molecule that were linked by two sets of N—H O hydrogen bonds. The piroxicam-saccharin synthons were in turn linked through bridging C—H O hydrogen bonds. Interestingly, the drug substance solubility out of the cocrystal was found to be comparable to that of the marketed piroxicam product. 

Cyt 2D6 metabolizes haloperidol, risperidone, thioridazine, sertindole, olanzapine and clozapine common substrates - fluoxetine, paroxetine, sertraline, venlafaxine, amitriptyline, clomipramine, desipramine, imipramine, nortriptyline, propranolol, metoprolol, timolol, codeine, encainide, flecanide. Common inhibitors - paroxetine, sertraline, fluoxetine. 

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... 

Quazepam Venlafaxine Amitriptyline Selegiline (deprenyl) Lithium carbonate Lithium carbcxiate controlled release Triazolam Haloperidol Propranolol Clonazepam Chlordiazepoxide Lithium carbonate slow release Lithium carbonate Lithium carbonate Loxapine Maprotiline Fluvoxamine Isocarboxazid... 

CYP2D6 Antidepressants amitriptyline, clomipramine, imipramine, desipramine, nortriptyline, trimipramine, N-desmethyl-clomipramine, fluoxetine, norfluoxetine, paroxetine, venlafaxine, sertraline Neuroleptics chlorpromazine, thioridazine, perphenazine, haloperidol, reduced haloperidol, risperidone, clozapine, sertindole Others codeine, opiate, propranolol, dextromethorphan 4 no activity 25% in Caucasians 0%-10% in others 5 no activity 2%-10% in all groups 10 reduced activity 47%-70% in Asians <5% in others 17 reduced activity 25%-40% in blacks 0% in others 2XN increased activity 19%-29% in Arabs and Ethiopians <5% in others... 

Fluvoxamine inhibits liver drug-metabolizing enzymes. Dosages of alprazolam, theophylline, and warfarin must be reduced if any of these drugs are given concomitantly with fluvoxamine. Nefazodone may also decrease the metabolism of benzodiazepines, and venlafaxine may inhibit haloperidol metabolism. The answer is (B). 

There are isolated cases of apparent interactions between clozapine, and ampicillin, buspirone, caffeine, haloperidol, loperamide, modafinil, nefazodone, nicotinic acid, tryptophan, or vitamin C. Grapefruit juice, influenza vaccine mirtazapine, reboxetine, or venlafaxine do not appear to interact Cocaine levels may increase when taken with clozapine. 

Venlafaxine can increase the serum levels of haloperidol. This is consistent with an isolated report, which describes a man who developed urinary retention when venlafaxine was added to a previously well-tolerated regimen of haloperidol and alprazolam. 

A study in 24 healthy subjects found that steady-state venlafaxine 75 mg every 12 hours reduced the renal clearance of a single 2-mg dose of haloperidol by 42%, resulting in a 70% rise in the AUC and an 88% rise in its maximum serum levels. " This rise in haloperidol levels would seem to be consistent with an isolated report of a 75-year-old man taking haloperidol 1 mg and alprazolam 500 micrograms daily, who suddenly developed urinary retention when venlafaxine 37.5 mg daily was added. 

It was suggested that venlafaxine inhibits the cytochrome P450 isoenzyme CYP2D6, which is concerned with the metabolism of haloperidol. As a result the serum levels of the haloperidol rise, thereby increasing its antimuscarinic effects, which in this case resulted in urinary retention. 

The evidence is very limited but be aware that increased haloperidol adverse effects may occur if venlafaxine is also given. It may be necessary to reduce the haloperidol dosage. 

Benazzi F. Urinary retention with venlafaxine-haloperidol combinaticm. Pharmacopsychiatry (1997) 30,27. 

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