Re: Antivirals -- doses, side effects, resistance (was Re: Antivirals - herxing?)

[Guest guest]

or how about getting an XMRV test at VIP Diagnostics? i am aware that the

existence of this virus is being hotly debated at the moment, but

antiretrovirals have sure helped me...and I have the blood tests to prove it.

>

> Thank you everyone for all your suggestions. I made a quick call to my

immunologist yesterday. As one of you mentioned, she also said that acyclovir is

very toxic to the kidneys & liver and needs to be monitored regularly. She said

that she had to hospitalize one of her patients for kidney problems from it. She

doesn't feel the studies are conclusive enough to recommend using it in high

doses. In the meantime, I've been told by both doctors to discontinue the

acyclovir. At this point, I'm not sure if I'll try it again at a lower dosage or

try something different. My biggest concern is that I'm not treating the

underlying problems of my CFS if I don't do the antivirals, so I need to do

something.

>

>

Joy, this is a very difficult situation, and I wish there were more definitive

answers for you. Sue makes a good point when she says that doctors are often not

helpful concerning CFS, but Nat also makes a good point that relying on an

internet list for medical advice is very, very risky. I don't think any of us

here are physicians (I'm not a physician), plus none of us have access to things

like your blood test results or your medical history. If you are experiencing

side effects and your doctors say to stop the acyclovir, it's safest to listen

to them. I agree that it's very frustrating not to be taking anything that might

treat the underlying cause of your CFS, but acyclovir doesn't seem to be helping

you.

Stopping the acyclovir now and then trying it (or a different antiviral) later

would also help you tell whether your recent worsening of symptoms was caused by

taking antivirals, or just happened to occur at the same time that you started

acyclovir.

Since we're talking about side effects of acyclovir, let me describe what I

know, just for general information (not to substitute for medical advice.) All

of this goes for Valtrex (valacyclovir), too.

Concerning the kidney effects of acyclovir, my understanding is the same as

Sue's--this side effect happens when acyclovir is taken without enough water.

Acyclovir and related antivirals (like Valtrex) are sometimes taken in such high

doses that there isn't enough water in the kidneys to keep the drug

dissolved--it's like if you stir lots and lots of sugar into water, some of it

won't dissolve. The undissolved antiviral drug then physically plugs up the

kidneys. The cases I've read about in the medical literature were in people who

received acyclovir intravenously, but it sounds like your immunologist maybe had

a patient who developed this problem after taking the drug by mouth.

In the cases of kidney problems with acyclovir that I read about, the treatment

was to " back wash " the kidneys by flooding them with water, and I don't think

any of the patients had permanent kidney problems. However, I would certainly

agree that patients taking high doses of acyclovir should have their kidneys

monitored (by blood tests) regularly. They should also make sure that they are

urinating regularly, and contact a doctor immediately if they aren't producing a

normal amount of urine, since lack of urine could be a sign of kidney blockage.

As for liver problems, in the interest of full disclosure, I should note that I

have mildly elevated liver enzymes, which theoretically could be a side effect

of the huge dose of Valtrex (8 grams a day) that I am on. However, I think my

elevated liver enzymes are probably NOT caused by the Valtrex, since my liver

enzymes have been elevated, on and off, for about twenty years--long, long

before I ever took Valtrex (and before I was ever diagnosed with CFS.) In fact,

my liver enzymes were more elevated 20 or so years ago than they are now.

( " Elevated liver enzymes " can be caused by many things, and are a sign that the

liver is under stress. They are detected by a blood test. My liver seems to do

its job fine even with the elevated enzyme levels--I don't have jaundice or

anything.)

From what I've read in the medical literature, any liver problems caused by

acyclovir or Valtrex are generally mild, since the liver is not involved in the

metabolism of these drugs. But yes, anyone on long-term Valtrex or acyclovir

therapy needs to have their liver checked regularly.

Overall, Valtrex (valacyclovir) is better absorbed and more effective than

acyclovir because it stays in the body longer. Unfortunately, Valtrex is very

expensive. There was a suggestion on this list that since Valtrex (valacyclovir)

is acyclovir bound to a part of a valine molecule, maybe taking valine (an amino

acid) together with acyclovir would be like taking Valtrex (valacyclovir).

I don't see how taking valine would improve the effectiveness of acyclovir.

First, since the valine wouldn't start off bound to the acyclovir, the valine is

not going to help the acyclovir get absorbed from the digestive tract. Secondly,

the body breaks down Valtrex into valine and acyclovir. The reason Valtrex lasts

longer than acyclovir in the body is that the body needs to break down the

Valtrex before excreting it in the urine. Since Valtrex naturally breaks down to

valine and acyclovir in the body, I don't see how valine would combine in the

body with acyclovir to make Valtrex.

OK, one more thing! There has been a lot of discussion here that taking lower

doses of antivirals may be safer than taking high doses. While low doses of

drugs are generally less likely to cause side effects, there is a real risk to

taking a low dose of any antibiological agent (such as antibiotics, antifungals,

and antivirals.) Taking low doses of an antibiological agent can encourage the

pathogen to develop resistance to that drug.

Luckily, herpes viruses tend to be very slow at developing resistance to drugs.

It does happen, though. The doctor who treats my allergies (not my CFS), Dr.

Baker of U. of MI, has been trying to treat patients with drug-resistant

Herpes Simplex 1 & 2. All of his patients who developed drug-resistant Herpes

Simplex started off with serious immune problems, and all of them had been

taking anti-herpes agents for at least a year. So, resistance to anti-herpes

agents doesn't happen often. Still, because of the possibility of drug

resistance, I think it's safer to start with a low dose of an anti-herpes agent

*and gradually INCREASE the dose* than to keep taking a low dose of an

anti-herpes agent for a long time (like, over six months.)

If a person can't afford much of an anti-herpes drug, taking a full dose for a

couple of weeks, followed by a month or two off the drug, may be safer than

taking a low dose for a long time.

-- Judith Shapiro