Quinidine Tricyclic antidepressants

Widening of the QRS complex duration to greater than 100 milliseconds is typical of tricyclic antidepressant and quinidine overdoses (Figure 59-1). The QTC interval may be prolonged to more than 440 milliseconds in many poisonings, including quinidine, tricyclic antidepressants, several newer antidepressants and antipsychotics, lithium, and arsenic (see also http //www.torsades.org/). Variable atrioventricular (AV) block and a variety of atrial and ventricular arrhythmias are common... 

Bicarbonate, sodium Membrane-depressant cardiotoxic drugs, eg, quinidine, tricyclic antidepressants... 

Amantadine is used cautiously in patients with seizure disorders, psychiatric problems, renal impairment, and cardiac disease. Amantadine is a Pregnancy Category B drug and is used cautiously during pregnancy and lactation. Concurrent use of antihistamines, phenothiazines, tricyclic antidepressants, disopyramide, and quinidine may increase the anticholinergic effects (dry mouth, blurred vision, constipation) of amantadine... 

Drugs that may interact with rifabutin include the following Anticoagulants, azole antifungal agents, benzodiazepines, beta blockers, buspirone, corticosteroids, cyclosporine, delavirdine, doxycycline, hydantoins, indinavir, rifamycins, losartan, macrolide antibiotics, methadone, morphine, nelfinavir, quinine, quinidine, theophylline, aminophylline, tricyclic antidepressants, and zolpidem. 

Drug interactions Serious and/or life-threatening drug interactions could occur between amprenavir and amiodarone, lidocaine (systemic), tricyclic antidepressants, and quinidine. Concentration monitoring of these agents is recommended if these agents are used concomitantly with amprenavir. 

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... 

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... 

Widening of the QRS complex duration to more than 100 milliseconds is typical of tricyclic antidepressant and quinidine overdoses (Figure 58-1). The QTC interval may be prolonged to more than 440 milliseconds in many poisonings, including... 

Bicarbonate, sodium Membrane-depressant cardiotoxic drugs (tricyclic antidepressants, quinidine, etc) 1-2 mEq/kg IV bolus usually reverses cardiotoxic effects (wide QRS, hypotension). Give cautiously in heart failure (avoid sodium overload). 

A large number of prescription and nonprescription drugs, as well as a variety of plants and mushrooms, can inhibit the effects of acetylcholine at muscarinic receptors. Some drugs used for other purposes (eg, antihistamines) also have anticholinergic effects. Many of them have other potentially toxic actions. For example, antihistamines such as diphenhydramine can cause seizures tricyclic antidepressants, which have anticholinergic, quinidine-like, and a-blocking effects, can cause severe cardiovascular toxicity. 

Tricyclic antidepressants, corticosteroids, coumarin anticoagulants, digitoxin, doxycycline, furosemide, oral contraceptives, quinidine, rifampin, theophylline, vitamin D... 

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

Cyt 3A3/4 metabolizes clozapine, sertindole, quetiapine common substrates -tricyclic antidepressants, nefazodone, sertraline, carbamazepine, ethosuximide, terfenadine, benzodiazepines, diltiazem, nifedipine, verapamil, erythromycin, cyclosporine, lidocaine, quinidine, cisapride, paracetamol. Common inhibitors -nefazodone, fluvoxamine, fluoxetine, ketoconazole. 

Figure 18-5. The separation of therapeutic tricyclic antidepressants on PBD-coated zirconia at different temperatures. Solutes 1, lidnocaine 2, quinidine 3, norephedrine 4, tryptamine 5, amitriptyline 6, nortriptyline. (Reproduced from reference 52, with permission. Copyright 1997, American Chemical Society.)...

Pseudobulbar affect SSRI antidepressants 20-100 mg QD Tricyclic antidepressants 20-100 mg QHS Mirtazapine 15-30 mg QHS Venlafaxine 37.5-75 mg BID-TID Dextromethorphan/quinidine 30mg/30mg BID Lithium carbonate 300 mg QD-TID... 

Drugs with anticholinergic effects (including pheno-thiazines, tricyclic antidepressants, quinidine, and diso-pyramide) will have their effects increased by antihistamines. 

Clinically important, potentially hazardous interactions with amiodarone, amitriptyline, amoxapine, benzodiazepines, bepridil, clomipramine, clonazepam, clorazepate, delavirdine, desipramine, diazepam, dihydroergotamine, doxepin, ergotamine, fentanyl, flurazepam, imipramine, ixabepilone, lidocaine, lorazepam, methysergide, midazolam, nortriptyline, oxazepam, phenytoin, protriptyline, quazepam, quinidine, rifampin, ritonavir, sildenafil, St John s wort, temazepam, tricyclic antidepressants, trimipramine, vitamin E... 

Clinically important, potentially hazardous interactions with aminophylline, amiodarone, antacids, antineoplastics, arsenic, bepridil, bismuth, bismuth subsalicylate, bretylium, calcium salts, cocoa, didanosine, disopyramide, duloxetine, erythromycin, iron, magnesium salts, meptazinol, methylxanthines, NSAIDs, phenothiazines, procainamide, quinidine, rasagiline, sotalol, sucralfate, tizanidine, tricyclic antidepressants, zinc... 

Clinically important, potentially hazardous interactions with amiodarone, arsenic, bepridil, bretylium, disopyramide, duloxetine, erythromycin, fenbufen, phenothiazines, procainamide, quinidine, sotalol, tricyclic antidepressants... 

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