Next "Case" - Chenoa - confirmed CHF but good update :)

[lilspaz68]

Most people would be heart broken, that their rat has CHF and their lifespan is likely to be a lot shorter, but I am thrilled I found the answer to make her more comfortable and happy for however long she's got. It will be nice to have a real fighting chance with a rat I can handle to treat and examine...the Wildlings were hands-off treatment and very difficult to help.

Now IF only Linny responds too, I will be ecstatic!

 

[PiedPiper]

:cheering: Go Linny, Go! :cheering: We likes our Shelagh to be happy!

 

[henry's_mum]

yes this is what they did for Daytona too. High end dose at first then drop it down to go back up again. I never thought to do that with rats as well, good to know!

:joy: GO GIRLS GO :joy:

 

[Godmother]

That's good info to know, about starting with high doses. I would have been afraid to do that, not knowing about the side effects (e.g. low b.p.) and how quickly it would be safe to change the dosages.

Are you giving her an ACE inhibitor & Lasix, or are you also adding Atenolol, Digoxin and/or a brochodilator?

 

[lilspaz68]

That's good info to know, about starting with high doses. I would have been afraid to do that, not knowing about the side effects (e.g. low b.p.) and how quickly it would be safe to change the dosages.

Are you giving her an ACE inhibitor & Lasix, or are you also adding Atenolol, Digoxin and/or a brochodilator?

No just the enalapril and lasix..just the basics for now.

 

[lilspaz68]

So I emailed Sarah at work asking what she had used for her piggies...listing all the meds Godmother had mentioned.

and asked permission to post this email (of course) since its chock full of another perspective...and I will take all I can get :wink2:

Typically it's ACE inhibitors and Lasix. It depends on what else is going on though - often guinea pigs with CHF are also having issues with URIs as the heart condition makes them more susceptible to infections. So while you're treating the heart you're also usually treating with antibiotics and anything else that will help with the lungs if they're compromised.

Bronchodilator aren't usually indicated if it's strictly a heart issue and there are no respiratory issues, but sometimes they go so hand in hand it's hard to know when there is only one issue at play. Or maybe the thinking is the lungs/airways are constricted because of excess fluid? The lasix would take care of that though... or an enlarged heart could be putting pressure on the airways? I'm not sure about that. I would try treating one thing at a time with as few medications as possible, and then add as needed to isolate the true cause and effect of meds (hope that makes sense!).

I myself have only used benazepril and lasix. The emergency doses typically used are 5-10 mg/kg for Lasix, only to start to take the animal out of failure (where they're gasping for air, not eating, limp, etc.), and 1-5 mg/kg of the benazepril or enalapril. Give that for a day or two, then start reducing the doses until you end up at something that works for the animal. The standard dose for the ACE inhibitors is 1 mg/kg, for lasix is 1-4 mg/kg.

http://www.guinealynx.info/cardiovascular_agents.html

The article on marvistavet on how enalapril works is really interesting. Also there are important interactions/concerns to be noted when giving lasix: http://www.marvistavet.com/html/body_furosemide.html

I never have to worry about them because we don't give gentamicin to gps but with the rats it's something to be aware of. With both drugs it's really really important to monitor kidney levels, but with rats I guess it's more difficult to do bloodwork for that.

Ideally you'd want to do bloodwork and x-rays to rule out anything else aside from heart and to check the kidney levels before initiating a treatment plan for heart. Then do further bloodwork to check kidney values after a week or so on heart meds.

The lasix isn't really supposed to be given longterm, except when absolutely necessary. I didn't have Maggie on Lasix until the regular heart meds were at a really high dose and she was still having difficulty breathing, then I gave her the lasix. Unfortunately you have to keep upping the doses at time progresses as the heart condition keeps getting worse.

I know nothing about atenolol.

Digoxin appears to be a very old med that is rarely used anymore, enalapril or benazepril would be much better choices. This is what Josephine (an exotics vet tech with approx. 20 yrs experience) said about digoxin in 2002 on GL:

You know, I don't know anyone who still uses it (the Digoxin) around here (except vets over 55 years old!). I do know that in high amounts, it causes toxicites. The margin of safety is very small in comparison to other drugs.

My formulary supports this. "There is still a lot of controversy over when to start digoxin therapy and which patients to treat..." (The Pill Book Guide to Medication for your Dog and Cat c 1998).

Usually Lasix and Enacard are the standards in today's veterinary medicine. The research supports the methodologies and pharmacology of the ACE-inhibitors (like Enacard) and their related efficacy. Enacard is tons safer than Digoxin (digitalis). I have no exotics references that state it is safe for cavies or related species.

 

[Alicemcmallis]

Would that be a typical age for heart troubles to start or progress?

In general I think it's more common as animals age, but can come on at any time. Certain factors may contribute to the development of heart conditions such as genetics, prior environment and diet, etc.

 

[Alicemcmallis]

A few of ours, we thought they had clear lungs, or couldn't hear anything off but a post would show the lungs were badly infected. Sadly, doing the telephone rat is a hit or miss.

I think this is very important to note. I have heard many times from different sources that even a vet listening with a stethoscope cannot detect any sounds in the lungs if they're either full of fluid or if the lungs are abscessed, hardened, etc. An x-ray is required to properly diagnose.

In this case the rat is responding well to heart meds, so a heart condition is likely the cause rather than a lung issue, but I think a lot of the time if the lungs are very compromised a simple course of antibiotics is not enough to make a noticeable difference and an infection may be dismissed as a possible issue.

 

[lilspaz68]

Linny never responded so I am going to try new meds, but Chenoa did well, and continues to do pretty good. Its not a cure, but she's happier and more active, her fur seems a little softer and her breathing is still a bit rapid but that is fine with me. We will enjoy our time however long that is.

Here she is cuddled up with Monkeyface aka Ashe. She wasn't even going to the top floor much less in the hammock before. :mrgreen:

 

[PiedPiper]

Yay! :joy: Hopefully Linny will respond to the new protocol. Fingers crossed that she does.

 

[SQ]

Enacard is tons safer than Digoxin (digitalis).

So does it do the same thing as digoxin?
What is the dossage for rats?

My vet doesn't like to give digoxin, but I insisted after reading that it is needed for rats that have large hearts.

When an xray shows that my rat has an enlarged heart, digoxin is added to their other heart meds .... it makes all the difference in the world.
But would rather use something safer that does the same thing ...

Shelagh, hope that both girls are soon feeling better.

 

[lilspaz68]

Enacard is a brand name of enalapril, just like Vasotec.

I started doing some research...found this article (without paying for it...hehe)

http://www.uptodate.com/patients/conten ... &refNum=23

I am going to paste it but put the comparison numbers more in easily readable form

TI Enalapril versus digoxin in patients with congestive heart failure: a multicenter study. Canadian Enalapril Versus Digoxin Study Group.
AU Davies RF; Beanlands DS; Nadeau C; Phaneuf D; Morris A; Arnold JM; Parker JO; Baigrie R; Latour P; Klinke WP; et al.
SO J Am Coll Cardiol 1991 Dec;18(7):1602-9.

Patients with New York Heart Association functional class II or III heart failure stabilized on furosemide therapy were entered into a randomized controlled trial comparing enalapril (n = 72) and digoxin (n = 73). End points were clinical outcome, treadmill exercise capacity and echocardiographic left ventricular dimensions. Improvement in clinical outcome was defined as a reduction of at least one functional class or withdrawal because of an adverse clinical event. After 4 weeks, 13 patients receiving enalapril showed improvement, 55 had no change and 9 manifested deterioration compared with 7, 49 and 17, respectively, in the digoxin group (p less than 0.01). After 14 weeks, 13 patients receiving enalapril showed improvement, 50 had no change and 9 manifested deterioration, compared with 14, 37 and 22, respectively, in the digoxin group (p less than 0.025). More patients in the digoxin group were withdrawn because of an adverse clinical event (p less than 0.05). Exercise time and percent fractional shortening improved in both groups (p less than 0.001 and less than 0.05, respectively), with no significant difference between groups (p greater than 0.50). Both rate-pressure product and subjectively evaluated exertion during submaximal exercise were reduced only in the enalapril group. Although the majority of patients in both groups did well, those receiving enalapril experienced fewer adverse clinical events and had less fatigue during submaximal exercise.

AD Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
PMID 1960303

Enalapril (after 4 weeks)
13 showed improvement
55 no change
9 deteriorated
Digoxin (after 4 weeks)
7 showed improvement
49 no change
17 deteriorated

Enalapril (after 14 weeks)
13 showed improvement
50 no change
9 deteriorated
Digoxin (after 14 weeks)
14 showed improvement
37 no change
22 deteriorated

More patients in the digoxin group were withdrawn because of an adverse clinical event

 

[lilspaz68]

I know this is a wiki article on Digoxin but it puts things pretty plainly from all my research.

http://en.wikipedia.org/wiki/Digoxin

Clinical use

Today, the most common indications for digoxin are probably atrial fibrillation and atrial flutter with rapid ventricular response. High ventricular rate leads to insufficient diastolic filling time. By slowing down the conduction in the AV node and increasing its refractory period, digoxin can reduce the ventricular rate. The arrhythmia itself is not affected, but the pumping function of the heart improves owing to improved filling.

The use of digoxin in heart problems during sinus rhythm was once standard, but is now controversial. In theory the increased force of contraction should lead to improved pumping function of the heart, but its effect on prognosis is disputable and other effective treatments are now available. Digoxin is no longer the first choice for congestive heart failure, but can still be useful in patients who remain symptomatic despite proper diuretic and ACE inhibitor treatment. It has fallen out of favor because it was proven to be ineffective at decreasing morbidity and mortality in congestive heart failure. It is shown to increase quality of life, however.

 

[Godmother]

That's really interesting, Shelagh! Thanks for posting it. Our dilemma has always been the lack of lab data for the rats, but I had never looked at the data for people.

Regarding the first study, it's a pity that there was not an arm of the study using both drugs. We also have to interpret the raw data carefully when doing comparisons: the raw data show a difference in withdrawal for adverse events, but the authors state that the significance result (p) was <.05. That means that you can't really bank on the difference in adverse events being different for the two drugs, despite differences in this particular sample.

I like the last article's summary paragraph:

Digoxin is no longer the first choice for congestive heart failure, but can still be useful in patients who remain symptomatic despite proper diuretic and ACE inhibitor treatment. It has fallen out of favor because it was proven to be ineffective at decreasing morbidity and mortality in congestive heart failure. It is shown to increase quality of life, however.

SQ's experience has been similar to mine. When we tried it on rats who had enlarged hearts and insufficient response to the Lasix & ACE inhibitor we got good results. Debbie Ducommun's Health Care booklets says not to use Digoxin unless the heart is enlarged (evidently it's not effective for a heart with thickened walls but normal size), and that means an X-ray. X-rays are prohibitively expensive in most big cities, so it's reasonable to be very cautious with Digoxin.

Now we need to track down the studies about quality of life. Our rats can't tell us, so we can only guess by looking at their activity level, appetite, and interest in their usual activities. I knew that Georgie was having a good quality of life til near the end, because she still stole food from her sisters and ran off with it! I wish I had tried more medication with Melissa, but I was less knowledgeable then and reluctant to risk side effects.

 

[SQ]

Digoxin is no longer the first choice for congestive heart failure, but can still be useful in patients who remain symptomatic despite proper diuretic and ACE inhibitor treatment. It has fallen out of favor because it was proven to be ineffective at decreasing morbidity and mortality in congestive heart failure. It is shown to increase quality of life, however.

When we tried it on rats who had enlarged hearts and insufficient response to the Lasix & ACE inhibitor we got good results. Debbie Ducommun's Health Care booklets says not to use Digoxin unless the heart is enlarged (evidently it's not effective for a heart with thickened walls but normal size), and that means an X-ray.

As Godmother said, this has been my experience with quite a few rats ...

All of the rats I have had with CHF have had enlarged hearts ... huge, huge hearts ...
The other heart meds helped but not enough.
Adding the digoxin greatly improved their quality of life ... allowing their lives to be extended a couple of months to up to 6 months or more.
(Without the benefits of the digoxin, I would have had them pts much sooner because of their quality of life.)
If anyone knows of a safer heart med. that does the same thing as digoxin, I would love to hear about it.

 

[Godmother]

I have been googling. Found a review from 2002 that stated

In patients who are symptomatic, ACE inhibitors along with digitalis and diuretics as initial therapy (triple therapy) have the greater potential to improve exercise tolerance and decrease the incidence of treatment failure compared with diuretics alone or a combination of diuretics and digitalis. Diuretics alone should not be considered for long-term therapy as plasma renin activity, angiotensin II, aldosterone, norepinephrine and vasopressin levels may increase.

.

I also found an article that tested what happened when patients who'd been on the combo of ACE inhibitor, Lasix and Digoxin had only the Digoxin withdrawn; they did worse. On the other hand a large trial (about 7800 patients in each group) comparing patients who did or did not get Digoxin in addition to the ACE inhibitor and Lasix found no difference in measures of quality of life.

I then found an article with an intriguing title, The Contemporary Use of Digoxin for the Treatment of Heart Failure. It's a recent review article from summer of 2008, by a major researcher. There is no abstract, and the 250-word extract doesn't give the punch line, so I have emailed the author for a reprint. Stay tuned.

Thanks, Lilspaz, for inspiring me to do this. I have meant to for months, but never got around to it. I like doing lit searches. (it beats cleaning cages and shaking raisins out of rat laundry!)

 

[Godmother]

Argggh! :gaah:
I got a reply from the author of the Digoxin article (after tracking him down to a new university that he moved to in October, after the first email bounced back to me). He said that he does not have any reprints. I emailed him back to ask specifically for an electronic copy, but have not received an answer. It is possible that the journal forbids the free handout of articles (it costs a fortune to buy one, and there is no abstract available).

My guess is that he is reluctant to share an article unless the person is a colleague, e.g. an MD or a cardiology researcher. Jorats or Lilspaz, do you think that your vets would request the article if I gave you the author's email? He might be happy to share it with a vet who has an interest in animal cardiology. If so, I will PM you the info.

 

[lilspaz68]

I can ask

Just tell me what she is asking for and I will email her

 

[Godmother]

Citation for the article is:


GS Francis. The Contemporary Use of Digoxin for the Treatment of Heart Failure
Circulation: Heart Failure. 2008;1:208-209

Author's email address is: [email protected]



I realize now that the article is very short. Maybe Dr. Munn would be able to get a copy sent from the U of T Medical Library.