DIGITOXIN
Chemistry - A cardiac glycoside, digitoxin occurs as a bitter tasting, odorless, white to pale buffcolored, microcrystalline powder. It is practically insoluble in water and one gram is soluble inapproximately 150 ml of alcohol.
Digitoxin is highly protein bound (97% in humans, 70-90% in dogs) and values generally are thesame in uremic patients. It is unknown if digitoxin enters the milk.
Digitoxin is extensively metabolized and the elimination half-life usually remains unchanged inrenal failure patients. The elimination half-life in dogs has been reported range from 8-49 hours.
Like digoxin, this apparent interpatient variability suggests that digitoxin serum levels msut bemonitored to optimize therapy and reduce the chance for toxicity. Digitoxin is usually not recommended for use in cats because of its "very long" half-life, but one study reported a t1/2 of only32 hours, although other values have been reported to be longer than 100 hours.
Pharmacology, Contraindications/Precautions,
Adverse Effects, Warnings, Overdosage, Drug Interactions - See the information listed for digoxin.
Storage, Stability, Compatibility
Digitoxin tablets should be stored at room temperature (15-30°C) and kept in well-closed containers. Digitoxin injection is hydrolyzed at pH's less than 3. It is said to be compatible with most available IV solutions and it is not compatible with acids or alkalies.Uses, Indications
Like digoxin, digitoxin is indicated for heart failure or atrial arrhythmias, butbecause it is metabolized by the liver to a greater extent, some clinicians feel that it should be usedinstead of digoxin in patients with diminished renal function. Others believe that digoxin may beused in these patients if adequate serum level monitoring is performed and dosage adjustments aremade as necessary. Digitoxin is not routinely used in cats and some clinicians state it iscontraindicated in this species.Pharmacokinetics - DIGITOXIN
Digitoxin has only one steroidal hydroxyl group (versus two for digoxin) andtherefore is much less polar. It is rapidly and nearly completely absorbed in the small intestine afteroral administration. It is unknown if the presence of food alters either the rate or extent ofabsorption.Digitoxin is highly protein bound (97% in humans, 70-90% in dogs) and values generally are thesame in uremic patients. It is unknown if digitoxin enters the milk.
Digitoxin is extensively metabolized and the elimination half-life usually remains unchanged inrenal failure patients. The elimination half-life in dogs has been reported range from 8-49 hours.
Like digoxin, this apparent interpatient variability suggests that digitoxin serum levels msut bemonitored to optimize therapy and reduce the chance for toxicity. Digitoxin is usually not recommended for use in cats because of its "very long" half-life, but one study reported a t1/2 of only32 hours, although other values have been reported to be longer than 100 hours.
Pharmacology, Contraindications/Precautions,
Adverse Effects, Warnings, Overdosage, Drug Interactions - See the information listed for digoxin.