(for veterinary information only)
BRAND NAMES: ADEKIN, AMANTA, AMANTAGAMMA, AMANTAN, AMANTREL, AMIXX, ANTADINE, ANTIFLU-DES, ATARIN, ATENEGINE, CEREBRAMED, ENDANTADINE, INFECTOFLU, INFLU-A, LYSOVIR, MANTADINE, MANTADIX, MANTIDAN, PADIKEN, SYMADINE, SYMMETREL, VIROIFRAL AND VIRUCID
When the NMDA receptor is antagonized or blocked by a medication such as amantadine chronic pain may be alleviated. Amantadine alone is not an effective analgesic but when combined with other pain relievers, it adds an extra dimension of pain relief. At this time veterinary experience with this drug is rather limited but it seems to be emerging as helpful addition to pain relief regimens for dogs and cats.
HOW THIS MEDICATION IS USED
Typical situations where amantadine might be used:
Amantadine can be given with or without food. Amantadine is usually given once or twice daily. If a dose is accidentally skipped, do not double up on the next dose but give the dose when it is remembered and time the next dose accordingly.
Mild side effects include agitation, gas or diarrhea when the medication is first started. These should resolve with time. Amantadine also has what are called "anticholinergic effects" which include dry mouth (manifested as increased thirst), urinary retention, increased heart rate. These could be problematic in the presence of other medications with similar effects or certain medical conditions.
INTERACTIONS WITH OTHER DRUGS
Trimethoprim/Sulfa (an antibiotic), quinidine (a heart medication), thiazide diuretics may decrease the excretion of amantadine, yielding higher blood levels, making amantadine stronger.
Other anticholinergic drugs, such as antihistamines, may enhance the anticholinergic effects of amantadine. These effects include dry mouth (possibly showing as more lip-licking or water consumption), difficulty urinating, increased heart rate.
Other drugs that increase activity/general stimulation may exacerbate the agitation side effect sometimes seen with amantadine. Selegiline, which is frequently used to treat senile cognitive dysfunction might be an unexpected member of this category of drugs.
CONCERNS AND CAUTIONS
Probably the biggest concern is that this medication is fairly new to veterinary use and a full catalog of what to expect with its use is not yet available. Right now amantadine is growing in popularity for pets and may prove to be an excellent complement to many pain relief regimens.
In human medicine it is recommended to have caution when considering its use in patients with kidney disease, seizure disorders, active psychoses, liver disease, or congestive heart failure. This means that side effects are more likely in these situations.
Amantadine is best used in conjunction with other pain relievers and requires at least a week of use before its effectiveness can be judged.
Amantadine has a narrow therapeutic range which means accurate dosing is important to avoid toxicity. Use of oral liquid formulations allow for more accurate dosing.
Page posted: 4/16/2008