Flusapex Drops - prescription required. Active Ingredient Frusemide. Each mL contains 10mg of Frusemide. Actions Frusemide is the most potent and commonly prescribed Loop of Henle diuretic, which causes excretion of sodium, potassium and water. Contraindications Use in patients with progressive renal disease if azotaemia increases or oliguria occurs during therapy. Use in patients with impaired hepatic function. Concurrent use with neomycin. Caution 📷 On prolonged medication monitor electrolyte balance and urea. Adverse Effects Metabolic alkalosis and dehydration. Dosage & Administration Give orally in divided doses Cats: 0.1mL – 0.2mL/kg bodyweight daily Dogs: 0.2mL – 0.4mL/kg bodyweight daily.