> I think the most common issue with ASA (and plavix) is that it's hard on the
> stomach. ASA seems to be better in this regard than plavix, probably in part
> because it's dosed every three days instead of daily.
My cat tolerated plavix for roughly 18 months. It was always given to
her after she had eaten. She did not appear to have tummy upset
The problem with high doses of aspirin in kitties, more so
than the tummy upset is that kitties lack an enzyme, produced
by the liver (glucuronyl transferase) that is required to metabolize
not only aspirin but also other NSAIDs. This means that it takes longer
for aspirin to clear the kitty's system (3 day dosing) and it makes it
much easier to overdose a kitty. Especially a compromised
If there are concerns, then one could further consult with one's vet
or have a liver panel done to see whether there are problems.
Additionally some NSAIDs can interfere with the function of ACE inhibitors.
ACE inhibitors work, in part by dilation of blood vessels in the kidneys and
some NSAIDs interfere with this dilation. I don't recall whether aspirin is one of
A baby aspirin is typically 81 mg of aspirin.
As far as a specific dose, the FATCAT study that is looking at the effect
of plavix vs. aspirin for prevention of a second clot in a group of kitties
that have already experienced a clot is:
"clopidogrel/plavix (18.75 mg PO q 24 hours) or aspirin (81 mg PO q 72 hours). The dosages chosen for the study drugs are based on the standard accepted dosing regimen for aspirin and preliminary data from clopidogrel pharmacodynamic studies."
"Antiplatlet aggregating therapy may be considered when severe left atrial
enlargement is present, when spontaneous echo contrast is evident in the LA or
LAV, or when cats have have had preveious thromboembolic episodes. Aspirin may
be used, dosed at approximately 80mg every three days. Other agents are presently
under investigation such as clopidogrel (Plavix). Low molecular weight heparin
drugs are added when cats have thromboembolic complications. Two particular
agents, enoxaparin (Lovenox) and dalteparin (Fragmin), have received the most
attention. Both drugs are expensive but appear to have a far greater safety margin
than unfractionated heparin. Fragmin (100 U/kg q 12-24hrs SQ) or enoxaparine
(1mg/kg q 12 hrs SQ) have been used relatively safely. This dose of fragmin,
however, may be too little- or the frequency too low, to be efficacious. Administration
rates of every 6 to 8 hours are generally impractical, however, for long term
administration. Hyperkalemia can occur acutely as a result of re-perfusion injury.
Continuous ECG monitoring is valuable during the first 3 days of hospitalization.
Periodic evaluation of BUN and electrolytes are useful."
Hope this helps.