Overview of Pimobendan for Canines and Felines
- Pimobendan, commonly known by the brand name Vetmedin®, is a phosphodiesterase III inhibitor with calcium sensitizing properties. It has been shown to improve survival times and quality of life (lowered syncope, dyspnea, exercise intolerance, and ascites) in dogs and cats suffering from congestive heart failure(CHF). Pimobendan is an oral medication commonly used in combination with other drugs such as an ACE-inhibitor and diuretic (furosemide).
- Pimobendan has also resulted in significant improvement in signs of heart failure when added to standard therapy for dogs with dilated cardiomyopathy and has contributed to improved survival in some dogs (Doberman Pinschers).
- Phosphodiesterase inhibitors block the inactivation of cyclic AMP increasing sympathetic tone and thus cardiac output.
- Following oral administration of pimobendan to a pet with CHF, the heart rate decreases and the contractility of the heart increases.
- The oral bioavailability of pimobendan in dogs is 60–63%. It is highly protein bound in plasma (93%) and has a plasma elimination half-life of approximately 30 minutes. The half-life of its principal active metabolite is approximately 2 hours. Virtually the entire administered dose is eliminated in feces.
- In humans with CHF, pimobendan has been shown to be associated with a slightly increased risk of death (1.8 x) vs. untreated controls. The balance between benefit and risk of treatment with pimobendan remains to be established in humans and in dogs.
- Pimobendan is approved in Europe and Canada to treat dogs with heart failure due to dilated cardiomyopathy or valvular insufficiency (mitral and/or tricuspid regurgitation).
- Pimobendan is a prescription drug and can only be obtained from a veterinarian or by prescription from a veterinarian.
- This drug has recently been approved for use in animals by the Food and Drug Administration.
Brand Names and Other Names of Pimobendan
- Veterinary formulations: Vetmedin® (Boehringer Ingelheim)
- Pimobendan may also be registered under the trade names UDCG-115 or Acardi®.
- Human formulations: None
Uses of Pimobendan for Dogs and Cats
- Treatment of heart failure due to dilated cardiomyopathy or valvular insufficiency (chronic mitral valve insufficiency).
Precautions and Side Effects
- While generally safe and effective when prescribed by a veterinarian, pimobendan can cause side effects in some animals.
- Pimobendan should not be used in animals with known hypersensitivity or allergy to the drug.
- Also, it is contraindicated in hypertrophic cardiomyopathies and clinical conditions where an augmentation of cardiac output is not possible for functional or anatomical reasons (e.g. aortic stenosis).
- Doses of pimobendan over 0.8 mg/kg/day over a period of 2 to 4 weeks may be associated with exaggerated myocardial contractility and jet lesions to the myocardium.
- Dogs in CHF should be monitored for arrhythmias during therapy. If detected, such arrhythmias should be treated appropriately.
- Vomiting, diarrhea, and inappetence are possible side effects of treatment with pimobendan.
- Pimobendan has not been evaluated in dogs used for breeding or are lactating or pregnant.
- Nervous system signs, including in coordination and seizures may also occur. Behaviorally pimobendan may cause uneasiness.
- Renal side effects include polyuria and polydipsia.
Pimobendan may interact with other medications. Consult with your veterinarian to determine if other drugs your pet is receiving could interact with pimobendan.
Such interactions may include:
- Pimobendan should be employed with caution with other positive inotropes.
- Because it is highly protein-bound, careful monitoring is necessary if it is to be used with other drugs that are highly protein bound.
- Concurrent use of beta-blockers or calcium-channel blockers may decrease pimobendan-induced effects on myocardial contractility.
How Pimobendan is Supplied
- Pimobendan is available in 1.25 mg, 2.5 mg, and 5.0 mg capsules.
Dosing Information of Pimobendan for Dogs and Cats
- Medication should never be administered without first consulting your veterinarian.
- The dosage prescribed may vary depending on the reason for prescribing.
- In dogs, the dose is may range from 0.05 to 0.15 mg per pound (0.1 to 0.3 mg/kg) every 12 hours. It recommended that each dose be given 1 hour before food.
- In cats, the dose is similar to that of dogs being 0.0125 mg per pound (0.25 mg/kg) oral every 12 hours. This often works out to be 1.25 mg tablet per cat twice daily.
- It is recommended to give Pimobendan on an empty stomach if possible.
- The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your pet feels better, the entire treatment plan should be completed to prevent relapse.
- It is recommended that your pet’s heart disease be monitored while on Pimobendan with periodic electrocardiograms (ECG)’s, blood pressure, clinical signs, weight, respiratory rate, heart rate, and echocardiograph findings.