And digoxin-induced

Phenytoin (diphenylhydantoin) 5-10 mg/kg for convulsing foals and digoxin-induced arrhythmias 1 -5 mg/kg, every 4 h for maintenance 10 mg/kg, once daily for digoxin-induced arrhythmias 10mg/kg, once daily for chronic myositis or intermittent arrhythmias i.v. i.v., i.m., p.o. p.o, p.o. 

Binnion PF. Hypokalaemia and digoxin-induced arrh3/tiimias. Lancet 1915 ) i, 343-4. Poole-Wilson PA, Hall R, Cameron IR Hypokalaemia, digitalis, and arrh3dhmias. Lancet (1975) i, 575-6. 

Shapiro W, Taubert K. Hypokalaemia and digoxin-induced arrh3/tiraiias. Lancet (1975) ii, 604-5. 

Read, W.O. and Welty, J.D. (1963). Effect of taurine on epinephrine and digoxin induced irregularities of the dog heart. J Pharmacol Exp Ther 129 283-289. 

Shapiro, W. and Taubert, K. (1975) Hypo-kalaemia and digoxin induced arrhythmias (letter). Lancet, 2, 604. 

Diarrheal conditions may decrease drug absorption as a result of reduced intestinal residence time. The absorption of several drugs was decreased in response to lactose- and saline-induced diarrhea [145]. Digoxin absorption from tablets was impaired in one subject who developed chronic diarrhea as a result of x-ray treatment [146]. Abdominal radiation or the underlying disease has been shown to reduce digoxin and clorazepate absorption [147]. A dosage form that provides rapid drug dissolution (e.g., solution) may partially resolve this problem. 

Phenytoin Adjunct in treatment of tricyclic antidepressant toxicity, muscle relaxant in treatment of muscle hyperirritability, treatment of digoxin-induced arrhythmias and trigeminal neuralgia... 

Treatment of atrial fibrillation is initiated to relieve patient symptoms and prevent the complications of thromboembolism and tachycardia-induced heart failure, the result of prolonged uncontrolled heart rates. The initial treatment objective is control of the ventricular response. This is usually achieved by use of a calcium channel-blocking drug alone or in combination with a 13-adrenergic blocker. Digoxin may be of value in the presence of heart failure. A second objective is a restoration and maintenance of normal sinus rhythm. Several studies show that rate control (maintenance of ventricular rate in the range of 60-80 bpm) has a better benefit-to-risk outcome than rhythm control (conversion to normal sinus rhythm) in the long-term health of patients with atrial fibrillation. If rhythm control is deemed desirable, sinus rhythm is usually restored by DC cardioversion in the USA in... 

Aminoglutethimide [ah me no glue TETH i mide] is useful in second line therapy for the treatment of metastatic breast cancer. It inhibits the adrenal synthesis of pregnenolone from cholesterol, and the extra-adrenal aromatase reaction responsible for the synthesis of estrogen from androstenedione. Aminoglutethimide is administered orally, and is metabolized by the hepatic cytochrome P-450 system to inactive products. Because of its ability to induce this system, its own metabolism is accelerated, and interactions that increase the metabolism of dexamethasone (see p. 275), theophylline (see p. 220) and digoxin (see p. 158) can occur. Aminoglutethimide causes transient CNS depression and a maculopapular rash. 

The bradycardia produced by digoxin can be enhanced by beta-adrenoceptor antagonists. Neostigmine enhances vagal activity and can aggravate bradycardia (410). An apparent interaction between sotalol and thiazide-induced hypokalemia, resulting in torsade de pointes (411), has prompted the withdrawal of the combination formulation Sotazide. 

The potential role of the calcium current in the genesis of arrhythmias was discussed above. Verapamil (M, which inhibits calcium influx, can suppress experimental arrhythmias30 Another calcium blocker, nifedipine ( 13a), inhibits irregular rhythms produced by calcium in isolated atrial preparations.31 The calcium antagonist TMB-6( lk) was reported to be as effective as lidocaine in suppressing digoxin-induced arrhythmias in dogs.32 As expected, inhibition of calcium influx leads to depression of cardiac contractility and atrioventricular conduction. 

Telithromycin has several clinically significant drug interactions similar to those for erythromycin. It is both a substrate and a strong inhibitor of CYP3A4. Coadministration of rifampin, a potent inducer of CYP, decreases the serum concentrations of telithromycin by 80%. CYP3A4 inhibitors (e.g., itraconazole) increase peak serum concentrations of telithromycin. Serum concentrations of CYP3A4 substrates (e.g., pimozide, cisapride, midazolam, statins, cyclosporine, phenytoin) are increased by telithromycin. Telithromycin also increases peak serum concentrations of metoprolol and digoxin. 

There was no important pharmacokinetic interaction between azimilide and digoxin, and digoxin did not appreciably alter azimi-lide-induced QTc prolongation. Ketoconazole did not alter the pharmacokinetics of azimilide to a clinically relevant extent, and therefore other CYP3A4 inhibitors are also unlikety to affect azimilide pharmacokinetics. Azimilide did not alter the pharmacokinetics of omeprazole to a clinically relevant extent, and is therefore unlikely to interact with other substrates of CYP2C19. 

The increased plasma levels of digoxin caused by verapamil are reported to increase both inotropism" and toxic effects. Verapamil may enhance the digoxin-induced elevation of intracellular sodium, which may increase the risk of arrhythmias.A synergistic effect on heart rate and atrioventricular conduction is also possible. 

Richter JP, Sommers De K, Snyman JR, Ivfillard SM. The acute effects of amilmde and potassium canrenoate on digoxin-induced positive inotrc i in healthy volunteeiB. EurJ Clin Pharmacol 99 ) 45,195-. ... 

Carbimazole abolished the systolic blood pressure decrease seen in the first 3 hours with digoxin, and also reduced the duration of the digoxin-induced diastolic blood pressure fall from 12 to 6 hours. The changes in heart rates, cardiac output and stroke volumes were not statistically significant, but inter-individual differences were large. " ... 

Clinical and laboratory observations. Am J Med 52 338-348 Bolton FG (1956) Thrombocytopenic purpura due to quinidine. Blood 2 547-564 Brauner GJ, Greene MH (1972) Digitalis allergy digoxin-induced vasculitis. Cutis 10 441-445... 

P-glycoprotein (P-gp) works as a transporter at the intestinal mucosa pumping drugs out into the lumen. Absorption of P-gp substrates, such as digoxin, cyclosporine, etc., can be increased by inhibitors of P-gp and reduced by inducers. 

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