Digoxin quinidine-induced

Chapron DJ, Mumford D, Pitegoff GI. Apparent quinidine-induced digoxin toxicity after withdrawal of pentobarbital, A case of sequential drug interactions. Arch Intern Med (1979) 139, 363-5,... 

Rifampin is known to induce the hepatic microsomal enzymes that metabolize various drugs such as acetaminophen, oral anticoagulants, barbiturates, benzodiazepines, beta blockers, chloramphenicol, clofibrate, oral contraceptives, corticosteroids, cyclosporine, disopyramide, estrogens, hydantoins, mexiletine, quinidine, sulfones, sulfonylureas, theophyllines, tocainide, verapamil, digoxin, enalapril, morphine, nifedipine, ondansetron, progestins, protease inhibitors, buspirone, delavirdine, doxycycline, fluoroquinolones, losartan, macrolides, sulfonylureas, tacrolimus, thyroid hormones, TCAs, zolpidem, zidovudine, and ketoconazole. The therapeutic effects of these drugs may be decreased. 

Memantine is not a major substrate for hepatic cytochrome P450 isoenzymes and has not been shown to significantly inhibit or induce these enzymes. However, memantine is partially excreted by renal tubular secretion. Thus, concomitant use of other medications that use the same renal system (i.e., triampterene, hydrochlorothiazide, digoxin, cimetidine, ranitidine, metformin, and quinidine) may affect plasma levels of both drugs (Namenda 2005). Memantine should not be used in combination with other NMDA receptor antagonists, such as amantadine or dextromethorphan, because these combinations have not been formally studied. The clearance of memantine can be reduced when the urine is alkalinized, such as with the concomitant use of sodium bicarbonate or carbonic anhy-... 

Galantamine (Razadyne) [Cholinesterase Inhibitor] Uses Alzheimer Dz Action Acetylcholinesterase inhibitor Dose 4 mg PO bid, T to 8 mg bid after 4 wk may T to 12 mg bid in 4 wk Caution [B, ] T Effect w/ suc-cinylcholine, amiodarone, dildazem, verapamil, NSAIDs, digoxin X- effect w/ anticholinergics, T risk of death vs placebo Contra Severe renal/hepadc impair Disp Tabs, soln SE GI disturbances, wt loss, sleep disturbances, dizziness, HA Interactions T Effects W/ amitriptyline, cimeddine, erythromycin, fluoxetine, fluvoxamine, ketoconazole, paroxetine, quinidine EMS Use succinylcholine w/ caudon, may need a reduced dose monitor ECG for induced conduction abnormalities OD May cause cholinergic Sxs (SLUDGE), muscle weakness, resp depression, and Szs atropine may be used as antidote... 

Drugs that are known to be substrates of P-gp include antihistamines (e.g. terfenadine), digoxin, ciclosporin, hydrocortisone and other steroids and drugs used in chemotherapy (e.g. paclitaxel, vinblastine). Ciclosporin, in addition to being a substrate of P-gp, is also an inhibitor of P-gp. Drugs known to induce P-gp include morphine, dexamethasone, phenobarbital, rifampin and St John s wort. Inhibitors of P-gp include amiodarone, amitriptyline, atorvastatin, chlorpromazine, ciclosporin, erythromycin, fluphenazine, haloperidol, quinidine, ritonavir and verapamil,... 

Phenobarbital and phenytoin increase metabolism of quinidine. Quinidine Increases plasma levels of digoxin, enhances vasodilator-induced hypotension and potentiates warfarin. 

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