When HCM has been diagnosed, there are usually several medications which are started at one time depending on the severity of the condition and whether or not congestive heart failure (CHF) is present.
1. Plavix is a commonly used drug in these patients.
2. If CHF is present,
a) a diuretic such as lasix is usually prescribed.
b) An ACE inhibitor such as enalapril is commonly administered. Interestingly enough, one study suggested that neither enalapril, atenolol nor diltiazem produced a favorable survival benefit in cats in heart failure from cardiomyopathy but these drugs are often still prescribed for these patients.
c) However, Vetmedin aka pimobendan may be beneficial.
3. In cats with severe SAM (Systolic anterior motion of the mitral valve which is common in these patients), atenolol is usually administered.
To summarize, the three drugs which have been prescribed for her are ones which are routinely used for feline patients with HCM.
I hope this helps and provides other drug options to discuss with your vet. Deb