What is Amantadine?
Amantadine hydrochloride is an antiviral medication that inhibits overactive nerve signals in the central nervous system (CNS). This occurs by antagonizing N-methyl-D-aspartate (NMDA) receptors in the nervous system which commonly transmits pain signals. Typically, when these pain pathways become overstimulated the animal will have a hypersensitivity to pain. Amantadine works to ‘reset’ the sensitivity to normal levels.
This medication is commonly used for animals with chronic pain for pain relief such as osteoarthritis, nerve pain, osteosarcoma, or neurologic disease. While amantadine can be used in both dogs and cats, it is seen to be more effective in dogs. Occasionally, amantadine can be used to treat pain in humans as well.
How Is It Given?
While it does work to block pain, amantadine is often used in conjunction with other pain medications — non-steroidal anti-inflammatory drugs (NSAIDs), opioids (such as Tramadol), Gabapentin, and Carprofen being among the most common. These medications will enhance the effects of Amantadine to give your pet pain relief.
Veterinarians will prescribe Amantadine in the form of tablets, capsules, or liquid depending on what is best for your pet. Typically, a bitter taste is associated with the medication, so often it is best to give with a treat or food.
Dosing:
| Form: | Dose: |
| Tablet | 193mg , 129mg , 100mg |
| Capsule | 137mg, 100mg, 68.5mg |
| Liquid | 10mg/ml |
Store amantadine in a cool, dry place and do not discard in household waste or water.
After administration, it may take up to 21 days for effects to show.
Side Effects
Within the first few days of giving amantadine, you may notice diarrhea and slight drowsiness in your pet. If these side effects persist for more than a few days, contact your veterinarian. Avoid giving doses of amantadine less than 8 hours apart as this can increase the likelihood of side effects such as vomiting and seizures.
Other side effects may include agitation, hyper-excitedness, ataxia, dry mouth, increased heart rate, difficulty breathing, and peripheral oedema.
With trimethoprim/sulfa (antibiotic): may cause high blood levels of amantadine.
With thiazide diuretics: raise blood levels of amantadine. With selegiline (anipryl): may cause more stimulation and excitement.
With anticholinergic drugs (Benadryl): increases severity of side effects – increased dry mouth, difficulty urinating, increased heart rate.
Amantadine can also alter organ functions, so it is best to take routine blood tests every 6 months to ensure everything is functioning correctly.
When to be Cautious
Despite the side effects, Amantadine is often given with other medication. Remember to tell your veterinarian all other medications and supplements your pet is taking to avoid unwanted side effects. Key medications to be aware of include anticholinergic drugs, CNS stimulants, trimethoprim/sulfa, quinidine, quinine, thiazide diuretics, triamterene, or urinary acidifiers.
Animals with untreated glaucoma, liver or kidney disease, congestive heart failure, eczematoid dermatitis, seizures, or those who are pregnant should avoid using amantadine.
Conclusion
Overall, Amantadine hydrochloride is a great option to help control your pets pain, but it is best to be cautious when giving any medication. If you think your pet may benefit from amantadine, consult with your veterinarian. And, as always, do your own research to better understand!
— Check out my post about Acepromazine (ACE) —
Sources
https://www.woodward-vets.co.uk/images/downloads/medication-leaflets/Amantadine.pdf
https://vcahospitals.com/know-your-pet/amantadine
https://www.vetspecialists.co.uk/fact-sheets-post/our-guide-to-amantadine