Enalapril for Cats

Enalapril (Enacard, Vasotec) is an ACE inhibitor used for high blood pressure control in cats. While the drug was developed for humans, it is given “off-label” to cats. Enalapril for cats is also used for heart failure, chronic kidney disease, and pulmonary hypertension. ACE inhibitors suppress an enzyme (angiotensin) that narrows the blood vessels, causing high blood pressure. Enalapril relaxes the veins and arteries, reducing the pressure on the walls.

Cost

Enalapril for cats is only available by prescription. The cost depends on whether the medication is generic, brand name or compounded in a veterinary pharmacy. Compounded liquid enalapril is available, as are chicken-flavored soft chews. The average cost of a 30-day supply of the tablets is $4.20 to $4.80, the compounded liquid is approximately $35, and the soft chews cost about $30.

Dosage

The dose of enalapril for cats is based on the cat’s weight and whether they have other medical conditions. Typical dosing for enalapril in cats is:

• 0.12 mg to 0.25 mg per pound, by mouth, once or twice daily

Dosage Instructions

Cats are not the easiest when it comes to administering medication. Some cats take tablets well, while others refuse entirely. The tablet can be crushed and given with a treat or food. If this doesn’t work, it might be a good idea to give them enalapril in liquid form. While this method is not foolproof it is usually easier to give than tablets. Chews are also available. 

When giving a tablet, place it on the back of the tongue and gently hold the cat’s mouth closed until they swallow. It may be helpful to restrain the cat by wrapping them in a large towel or blanket with just their head out. A friend or family member could be of assistance in keeping the cat calm. 

Gently raise the cat’s top lip when inserting an oral syringe with the medication into their mouth, behind their last tooth, and squirt the liquid to the back of the tongue. The cat may spit some out, but don’t try to give them more at this time. Wait until the next dose to try again. Never double dose or give extra doses with enalapril. Be sure to offer plenty of water to avoid dehydration in your feline.

Efficacy

While there have been few enalapril efficacy studies in cats, there is ongoing interest in cat-specific treatment with the drug. Anecdotal evidence exists of enalapril’s ability to lower blood pressure, but additional scientific testing is needed. One study concluded that enalapril is well-tolerated and can be useful in heart muscle enlargement caused by high blood pressure, pulmonary hypertension, and kidney failure. Eleven of 19 cats involved in the study had heart failure at the start, but only one ended the study with it.

Side Effects

Common side effects of enalapril to watch for include:

• Loss of appetite

• Vomiting

• Diarrhea

• Fatigue

• Lethargy

• Fever 

• Weakness

• Rash

• Low blood pressure

• Kidney dysfunction

• Increased levels of potassium

• Collapse

Your veterinarian will monitor your cat for serious side effects. Enalapril for cats is short-acting and is flushed out of the system in about 24 hours. At that point, side effects should be receding.

Considerations

Several risk factors and cautions exist such as acute kidney injury or certain heart diseases that may predispose them to problems with enalapril. It should be used with caution in felines with kidney or liver disease, heart failure, dehydration, low sodium levels, blood abnormalities, or vascular diseases. Gas anesthesia effectiveness may be affected with use, and extreme caution should be used in cats who are pregnant or lactating.

Drug Interactions

A number of medications may cause unwanted interactions with enalapril (Vasotec, Enacard). These drugs include:

• Anesthetics (ketamine, propofol)

• Antacids (cimetidine)

• Antihypertensive agents (amlodipine besylate)

• Vasodilators (nitroglycerin, hydralazine, minoxidil)

• Potassium-sparing diuretics (spirinolactone, amiloride)

• NSAIDs (ibuprofen, naproxen sodium, aspirin)

• Opioids (hydrocodone, oxycodone, fentanyl)

• Potassium supplements (potassium chloride, potassium citrate, phosphate)

• Diuretics (hydrochlorothiazide, furosemide, metolazone)

• Corticosteroids (cortisone, hydrocortisone, prednisone)

• Red blood cell producer (erythropoietin)

• Cardiac antiarrhythmics (digoxin, disopyramide)

• Antihistamines (dyphenhydramine)

• Antidepressant/anti-anxiety drug (doxepin)

• Anticoagulants (heparin, warfarin)

• Anti-gout medication (probenecid)

• Pulmonary hypertension medication (sildenafil)

Allergic reactions and sensitivity:

Cats may have an allergic reaction to enalapril. Signs are swollen lips, face or tongue, hives, and breathing difficulties. Your veterinarian will monitor your cat’s electrolyte levels, kidney test values, and the amount of protein in their urine. Testing is done every 1-2 weeks initially, then every 3 months. They will also monitor your cat’s blood count and blood pressure to gauge how well the enalapril is working.

Frequently asked questions

Can I get enalapril over-the-counter at a pharmacy?

No, you will need a prescription from a veterinarian to obtain enalapril for cats.

How do I store enalapril?

This medication should be stored at room temperatures of less than 86⁰F, away from light and moisture.

What if I miss a dose of enalapril for cats?

If it is close to the missed dose time, give it as soon as you think of it. If the missed dose is close to the time of the next dose, skip it and re-start on schedule with the next dose.

What do I do in case of an emergency?

If your cat appears to exhibit signs of an allergy or hypersensitivity to enalapril, or if you suspect an overdose, get them to the veterinarian or emergency vet hospital as soon as possible.