Amlodipine Besylate Side Effects in Cats

Amlodipine Besylate is a generic medication that is prescribed for treatment of hypertension, or high blood pressure, in cats. A 'calcium channel blocker', the medication works on arterial muscle by blocking calcium entry into the muscle cells. This decrease in calcium allows the blood vessel to dilate and decreases the pressure of blood flow. It is commonly prescribed for cats with systolic blood pressure that exceeds 160mmHg due to kidney failure, hyperthyroidism or hypertrophic cardiomyopathy. Cats suffering from these conditions are at high risk for permanent damage to the brain, the eyes, the heart or the kidneys.

Treatment with Amlodipine Besylate should include regular physical examinations and blood pressure monitoring. It is important to follow the treatment plan to avoid risk of dangerous side effects.

Side Effects of Amlodipine Besylate

Amlodipine Besylate can work in excess of the desired results and cause hypotension. Hypotension is low blood pressure due to excessive dilation of the arteries. Hypotensive cats will appear lethargic, depressed or weak. It can also effect the muscles of the heart by making contractions weaker and less efficient for pumping blood. Other possible side effects of the medication include:

  • Lethargy
  • Loss of appetite
  • Weight loss
  • Rapid heart rate
  • Gingival hyperplasia (swelling of the gums)

Examination and laboratory blood testing may show other side effects such as an elevation in renal blood parameters or a drop in blood potassium levels.

Allergic Reaction to Amlodipine Besylate

Some cats may experience an allergic reaction to Amlodipine Besylate. Onset of symptoms will occur within a short time of administering the medication. The symptoms of an allergic reaction include:

  • Facial swelling
  • Hives
  • Scratching
  • Diarrhea
  • Vomiting
  • Shock
  • Seizures
  • Pale gums
  • Cold limbs
  • Coma

Amlodipine Besylate Dosage Precautions

Amlodipine Besylate is prescribed for oral administration once or twice a day, and can be given with or without food. The dosage prescribed for cats often requires cutting the small tablets in halves or in quarters. A pill cutter should be used to ensure that the correct dosage is being administered. Overdosing of the medication can cause toxicity with symptoms such as dizziness or decreased heart rate. An overdose of the medication may result in collapse.

Doses of the medication must be given consistently for effective treatment. Missing a dose of the medication can cause an immediate increase in blood pressure and an onset of symptoms of hypertension. Sudden relapse of hypertension can result in:

  • Detached retinas
  • Blindness
  • Kidney damage
  • Thickening of the heart
  • Seizures
  • Stroke
  • Collapse

It is important to contact a veterinarian for instructions if a dose is missed. A veterinarian will determine if the dose can still be given safely or if the medication should be resumed at the next scheduled dose. A doubled dose after one that is missed can cause an overdose and toxicity.

Contraindications to Amlodipine Besylate

Amlodipine Besylate can have negative interactions with nonprescription vitamins, supplements and aspirin. If administered at the same time, other prescription medications may increase the risk of hypotension. The veterinarian should be informed if the cat is currently prescribed medications such as:

  • Warfarin
  • Diuretics (furosemide)
  • ACE inhibitors (enalapril)
  • Beta-blockers (propranolol)
  • Other medications that lower blood pressure

Amplodipine Besylate should be used with caution in animals that are suffering from heart failure or liver disease. Cats suffering from liver disease will require modification of dosing to gradually decrease and stop the medication. Breeding cats, and females that are pregnant or lactating, should not be prescribed Amlodipine Besylate.