First, I am sorry to hear about Pepper's most recent misadventure, but am so happy that
you caught the fluid build-up by your careful observation! I wonder whether or not I
would notice that subtle change in breathing pattern that you have described a few times
I have not used HCTZ, but understand that it is a thiazide diuretic. Thiazide diuretics
effect the renal system differently than loop diuretics like furosemide (loop refers to the
place where the drug has its effect - the "loop of Henle" which is part of the renal system).
Loop diuretics effect the sodium/potassium transporters in the loop of Henle. Thiazide
diuretics influence a sodium transporter in a different part of the renal system (the distal
tubules). The thiazide diuretics generally have a longer lasting effect than loop diuretics,
and some reports claim that they may be more helpful in treating generalized edema and
lowering blood pressure than other diuretics (the edema part seems a bit controversial).
Spironolactone, as you know, is an aldosterone antagonist with diuretic effects. It works
somewhat differently than the others by acting as an aldosterone receptor blocker. Often,
when one kind of diuretic is not enough to control fluid accumulation, another is added
that works at a different site or via a different mechanism.
Atrial fibrilliation, as you know, is an abnormal contraction of the atrium. It occurs when
the electrical impusles that cause the atrial chamber of the heart to contract are not
conducted properly. It can result in plueral effusion in addition to pulmonary edema. It
can be either chronic or acute and although digoxin is usually contraindicated in HCM, it is
sometimes added to the drug treatments when a cat has atrial fibrillation, often with a
beta-blocker (but if I recall correctly Pepper did not do well on atenolol). I think the
abnormal contraction of the left atria also increases the risk of clotting over LA
I hope some of this information is useful to you.
Good luck with Pepper! I am glad she is not acting like she is sick.
We are thinking of you!
-Nala, Camille and Cozette