Amlodipine besylate is a calcium channel blocker that is used to reduce blood pressure in cats and dogs.Hypertension, or high blood pressure, can be brought on by several conditions, including hyperthyroidism, kidney disease, hypertrophic cardiomyopathy, and heart failure. Amlodipine besylate for dogs decreases blood pressure by relaxing the arterial muscles which allows them to dilate.
The cost of amlodipine besylate depends on the formulation and dosage. Tablets are generally sold per tablet, and range from $0.10 to $1.60 each, with 90 count bottles averaging $8 to $10. Oral solutions can vary in dosage strength, and cost between $30 to $65. Transdermal gel is available in pens and syringes with varying strengths and pre-measured doses, and can range from $15 to $140 each.
Amlodipine besylate for dogs is usually available in 2.5 mg, 5 mg, or 10 mg tablets. It can also be given as an oral solution, soft chews, or a transdermal gel. A general dosing guideline is as follows:
- 0.1 mg – 0.4 mg per kilogram of weight, once to twice daily
Your veterinarian will usually need to adjust this dosage to give the maximum level of action without adverse side effects, starting with the lowest dosage and increasing it as needed. Dosage amounts can also depend on the patient’s condition, and if other drugs are being administered at the same time. Often, for systemic hypertension, dosages tend to be on the higher end.
Amlodipine besylate for dogs is administered by mouth once to twice daily through a tablet or oral solution. If using a liquid solution, be sure to measure the dose carefully. This medication can be given with or without food. If any vomiting or nausea occur on an empty stomach, give future doses with food. Be sure to give amlodipine besylate to your dog exactly as prescribed. Do not stop giving this medication or skip a dose, as it can result in a drastic rise in blood pressure which can have serious consequences.
While amlodipine besylate begins to act within hours, results are usually not visible. Your veterinarian will need to monitor your dog to be sure the medication is working.
.One study that looked at the efficacy of amlodipine besylate for dogs with acute kidney injury saw a significant decrease in systolic systemic blood pressure after use. In 90% of treated dogs, severe systemic high blood pressure was corrected.
.Another study measured amlodipine besylate’s effect on lowering left atrial pressure (LAP) in dogs suffering from mitral regurgitation (MR). The medication significantly decreased LAP, which increased cardiac output, suggesting to the researchers that amlodipine besylate is beneficial in treating dogs with MR.
Side effects of Amlodipine Besylate
Adverse reactions are rare with amlodipine besylate, but can include:
- Loss of appetite
- Weight loss
- Slight increase in heart rate
- Gum swelling
- Gingival hyperplasia
If these serious side effects are seen, discontinue use and contact your veterinarian immediately:
- Severely low or fast heart rate
- Severe weakness
- Changes in urination
- Abnormal bleeding due to decreased clotting ability
- Limb swelling
- Signs of allergic reaction, including hives, difficulty breathing, and facial swelling
Gingival hyperplasia is an overgrowth of the gums, which can lead to bacterial infections. Let your veterinarian know if you notice this condition, as it can be resolved within months of discontinuing amlodipine besylate treatment.
In humans, amlodipine besylate can cause headaches, though these are difficult to detect in dogs.Symptoms of headaches in dogs can include keeping their head lowered, avoidance of contact near head, or anxious behavior.
Amlodipine besylate should not be given to dogs who are allergic to it, or are suffering from liver failure, aortic stenosis, or shock. This medication should be used with caution in dogs with liver disease, heart disease, or any condition that causes them to be at greater risk of low blood pressure. Breeding males, and breeding, pregnant or lactating females should not take amlodipine besylate.
Missing a dose of this medication can cause a severe drop in blood pressure, and should be avoided due to serious complications. Use of amlodipine besylate for dogs can cause longer blood clotting times.
Amlodipine besylate (Norvasc, Istin, Amodip, Copalia, Katerzia) may interact with the following drugs, and should be used with caution:
- ACE inhibitor (enalapril)
- Antibiotic (rifampin)
- Antifungal medications (ketoconazole, itraconazole)
- Anticoagulant medications (clopidogrel, warfarin)
- Beta-blockers (propranolol, atenolol)
- Blood pressure medications
- Diuretics (furosemide)
- Hypotensive agents
- Immunosuppresive medications (cyclosporine, tacrolimus)
- Negative chronotropic medications
- NSAID (aspirin)
- Opioid pain-reliever (fentanyl)
Grapefruit juice can alter the absorption of this medication. Be sure to tell your veterinarian of all medications, herbal therapies, vitamins, and supplements your dog is taking before starting treatment.
Allergic reactions and sensitivity
Allergic reactions are always possible with any mediation. Signs of an allergy or sensitivity to amlodipine besylate in dogs can include sudden diarrhea, vomiting, difficulty breathing, hives, pale gums, or swelling in the face, throat, lips, or tongue. In severe cases, shock and coma can occur.
Frequently asked questions
What if I miss giving my dog a dose of amlodipine besylate?
It is very important to stay on schedule when administering amlodipine besylate for dogs. When a dose is missed, blood pressure can increase suddenly, which can cause kidney damage, blindness, seizures, or even collapse. In the event of a missed dose, give your dog the dose as soon as you remember, or if it’s close to the time for the next dose, skip the missed dose and give the regularly scheduled dose on time. Never administer two doses at the same time.
Does my veterinarian need to monitor my dog while taking amlodipine besylate?
Your veterinarian will need to monitor your dog periodically to make sure the medication is working, and check for any adverse reactions. Your dog’s blood pressure, potassium levels, and eyes will usually be checked at these appointments.
How is amlodipine besylate stored?
Store amlodipine besylate at room temperature (between 68°F and 77°F) and away from light, moisture, and heat.
What do I do in case of an emergency?
If you suspect your dog is having an allergic reaction to amlodipine besylate or has overdosed, contact your veterinarian or emergency veterinary hospital immediately. Symptoms of an amlodipine besylate overdose include dizziness, vomiting, staggering, weakness, lethargy, slow heart rate, and collapse.