Tricyclic antidepressants thioridazine

Drugs that may be affected by duloxetine include drugs extensively metabolized by CYP2D6 (eg, flecainide, phenothiazines, propafenone, tricyclic antidepressants, thioridazine), alcohol, CNS-acting drugs, MAOIs, and drugs highly bound to plasma proteins (eg, warfarin). 

Alprazolam Cimetidine Contraceptives Diazepam Erythromycin Fluoxetine Fluvoxamine Haloperidol Levomepromazine Methylphenidate Paroxetine Perphenazine Tricyclic antidepressants Thioridazine Thyroxine... 

Ziprasidone is well tolerated. Its common side effects are drowsiness, nausea, and constipation. Though there were initial concerns about untoward cardiological side effects similar to those produced by thioridazine and the tricyclic antidepressants, ziprasidone appears to be safe though it should probably not be used in patients with preexisting heart disease. 

Inhibitors codeine, encainide, flecainide, fluoxetine, haloperidol, hydrocodone, 4-methoxy-amphetamine, metoprolol, mexiletine, oxycodone, paroxetine, propafenone, propoxyphene, risperidone, selegiline (deprenyl), thioridazine, most tricyclic antidepressants, timolol Fluoxetine, haloperidol, paroxetine, quinidine... 

Inhibitors Inducers thioridazine, most tricyclic antidepressants, timolol Fluoxetine, haloperidol, paroxetine, quinidine Unknown... 

Tricyclic antidepressants, like some of the phenothiazine derivatives (e.g., thioridazine), have an anticholinergic property. Amitriptyline is the strongest in this regard, and desipramine is the weakest. 

Various factors may account for the variability in response to neuroleptics. These include differences in the diagnostic criteria, concurrent administration of drugs which may affect the absorption and metabolism of the neuroleptics (e.g. tricyclic antidepressants), different times of blood sampling, and variations due to the different type of assay method used. In some cases, the failure to obtain consistent relationships between the plasma neuroleptic concentration and the clinical response may be explained by the contribution of active metabolites to the therapeutic effects. Thus chlorpromazine, thioridazine, levomepromazine (methotrime-prazine) and loxapine have active metabolites which reach peak plasma concentrations within the same range as those of the parent compounds. As these metabolites often have pharmacodynamic and pharmacokinetic activities which differ from those of the parent compound, it is essential to determine the plasma concentrations of both the parent compound and its metabolites in order to establish whether or not a relationship exists between the plasma concentration and the therapeutic outcome. 

The interaction of thioridazine with a tricyclic antidepressant is particularly dangerous, since both cause cardiac toxicity. One report concerned two young patients who developed ventricular dysrhythmias, from which they recovered (215). 

Heiman EM. Cardiac toxicity with thioridazine-tricyclic antidepressant combination. J Nerv Ment Dis 1977 165(2) 139-43. 

There was no association of lithium with QTC prolongation but it was associated with nonspecific T-wave abnormalities (odds ratio 1.9) and increased QT dispersion (odds ratio 2.9). Caution was suggested if lithium is used with drugs associated with QTC prolongation, such as tricyclic antidepressants, droperidol, and thioridazine. 

Several factors increase the risk of thioridazine toxicity pre-existing cardiac disease, hypokalemia, a glucose load, alcohol, exercise, and concomitant therapy with tricyclic antidepressants, erythromycin, co-trimoxazole, cisapride, risperidone, hydroxyzine, and drugs that inhibit CYP2D6 (some SSRIs, fluphenazine, and perphenazine) (11). 

Of the systemic antihistamines, the ethanolamines, including diphenhydramine, have significant antimuscarinic activity. In addition, the antipsychotic agents, particularly the phenothiazines such as thioridazine (Mellaril), have well-dociunented anticholinergic properties. Therapeutic doses of tricyclic antidepressants, like amitriptyline hydrochloride (Elavil) and imipramine (Tofranil), produce significant anticholinergic actions and thus have the potential for ocular side effects. 

Clinically important, potentially hazardous interactions with flecainide, imipramine, potent CYP3A4 inhibitors, thioridazine, tricyclic antidepressants... 

Clinically important, potentially hazardous interactions with albuterol, alpha-blockers, amitriptyline, amoxapine, atenolol, beta-blockers, carteolol, chlorpromazine, clomipramine, cocaine, desipramine, doxepin, ephedra, ergotamine, furazolidone, halothane, imipramine, insulin detemir, MAO inhibitors, metoprolol, nadolol, nortriptyline, oxprenolol, penbutolol, phenelzine, phenoxybenzamine, phenylephrine, pindolol, prazosin, propranolol, protriptyline, sympathomimetics, terbutaline, thioridazine, timolol, tranylcypromine, tricyclic antidepressants, trimipramine, vasopressors... 

Clinically important, potentially hazardous interactions with amphetamines, aprepitant, astemizole, atazanavir, azithromycin, azole antifungals, clarithromycin, darunavir, dirithromycin, erythromycin, fluoxetine, fosamprenavir, grapefruit juice, imatinib, indinavir, itraconazole, ketoconazole, methylphenidate, nefazodone, nelfinavir, nilotinib, pemoline, phenothiazines, protease inhibitors, quinidine, ritonavir, saquinavir, sertraline, sparfloxacin, sulpiride, telithromycin, thioridazine, tipranavir, tricyclic antidepressants, troleandomycin, voriconazole, zileuton, ziprasidone... 

Clinically important, potentially hazardous interactions with amiodarone, amisulpride, amitriptyline, amoxapine, arsenic, bepridil, bretylium, calcium, chlorpromazine, clomipramine, desipramine, disopyramide, doxepin, erythromycin, fluphenazine, imipramine, iron salts, magnesium, mesoridazine, nortriptyline, pentamidine, perphenazine, phenothiazines, pimozide, procainamide, prochlorperazine, promazine, promethazine, protriptyline, quinidine, sotalol, sucralfate, thioridazine, tricyclic antidepressants, trifluoperazine, trimipramine, zinc salts... 

Drug-Drug and Drug-Food Interactions. Since cinacalcet is metabolized by multiple hepatic enzymes there is potential for drug interactions. Cinacalcet is also a potent inhibitor of the enzyme CYP2D6. As a result, dose adjustments of concomitant medications that are predominantly metabolized by this enzyme and have a narrow therapeutic index such as flecainide, thioridazine, vinblastine, and most tricyclic antidepressants (i.e., amitriptyline) may be required. ... 

Other drugs associated with prolongation of the QT interval include thioridazine and tricyclic antidepressants. 

Adenosine and magnesium are two unclassified antiarrhythmic drugs. Adenosine decreases SA and AV node activity and increases the AV node refractory period. Magnesium has possible use in torsades. Drugs (other than classes la and III antiarrhythmics) associated with torsades include thioridazine and tricyclic antidepressants. 

Other drugs associated with torsades include cisapride, erythromycin, thioridazine, and tricyclic antidepressants (TCAs). 

Tricyclic antidepressants, like some of the phenothiazine derivatives, are sedative in nature. Those compounds containing tertiary amines (imipramine, amitriptyline, and doxepin) are the most sedative. Those compounds containing a secondary amine (nortriptyline and desipramine) are less so, and protriptyline has no sedative effect (see Table 5). Tricyclic antidepressants, like some of the phenothiazine derivatives (e.g., thioridazine), have an anticholinergic property. Amitriptyline is the strongest in this regard, and desipramine is the weakest (see Tables 5 through 7). 

Procyclidine may reduce the antipsychotic effectiveness of haloperidol and phenothiazines, possibly by direct CNS antagonism related to its anticholinergic properties. Haloperidol and phenothiazine exert their effects in part by blocking the hyperactivity of dopaminergic transmission in the mesocortical and mesolimbic systems. Concomitant use with phenothiazine derivatives, especially thioridazine having pronounced anticholinergic effects, also increases the risk of anticholinergic adverse effects. Paralytic ileus may result from concomitant use with phenothiazines or tricyclic antidepressants. Concomitant use with alcohol and other CNS depressants increases procyclidine s sedative effects. 

PRAZEPAM, see Benzodiazepines PROCHLORPERAZINE, see Phenothiazines, piperazine PROTRIPTYLINE, see Tricyclic antidepressants TEMAZEPAM, see Benzodiazepines THIORIDAZINE, see Phenothiazines, piperidine THIOTHIXENE... 

Wong, S.H.Y. McHugh, S.L. Dolan, J. Cohen, K.A. Tricyclic antidepressant analysis by reversed-phase liquid chromatography using phenyl columns. J.Liq.Chromatogr., 1986, 9, 2511-2538 [also acetaminophen, amobarbital, amoxapine, barbital, chlordiazepoxide, chlorpromazine, cimetidine, clomipramine, codeine, desipramine, desmethyldoxepin, diazepam, doxepin, fluphenazine, flurazepam, glutethimide, hydroxyamoxapine, imipramine, lorazepam, maprotiline, meperidine, metabolites, nortriptyline, oxazepam, pentobarbital, perphenazine, phenobarbital, phenytoin, propoxyphene, protriptyline, secobarbital, thioridazine, trazodone]... 

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