VPT 311: General and Systemic Veterinary Pharmacology (2+1)

Precautions and drug interactions

PRECAUTIONS AND CONTRAINDICATIONS

• Hypokalemia will lead to increased digitalis toxicity
• In elderly patients and in patients with renal and severe hepatic disease the toxicity will be higher
• Thyrotoxicosis reduces the responsiveness to digitalis
• Myxoedema increases the responsiveness to digitalis
• Partial A-V block may be converted to complete A-V block

DRUG INTERACTIONS

• Diuretics – potassium depleting diuretics precipitate digitalis toxicity while potassium sparing diuretics reduce the renal excretion of digitalis
• Calcium precipitates digitalis toxicity
• Quinidine reduces binding to proteins and thereby increase the concentration and toxicity of digitalis
• Verapamil and diltiazem increase plasma concentrations of digoxin
• Antacids and neomycin reduce absorption of digitalis.