Tasmar and Liver (cont.) 1 December 1998
As (I think) I mentioned just before the Thanksgiving holiday, I
reluctantly decided to quit Tasmar, until more is known about a
very rare but extremely dangerous side effect, fulminant
hepatitis. I'm now back to 800mg/day, vice the former 400mg/day
of Sinemet, and unhappy about it. BTW: Tasmar, like many other
drugs, should not be stopped abruptly- see your neuro first.
The crux of the matter is ignorance about fulminant hepatitis
(FH). Unlike most other liver diseases, FH external symptoms
develop within a few hours, followed shortly, if not
treated, by coma and death. Encephalopathy (e.g., coma) is
a hallmark. The last I knew, 3 deaths from FH were reported
among the 100,000 or so Tasmar recipients in the past couple of
years, prompting suspension of approval in Europe and warning
letters to doctors in the U.S. and Canada. It's unclear how FH
incidence among Tasmar users compares with that in the general
population. One recent review mentions studies of 364 cases
in the general population worldwide, and one warning letter
suggests "10- to 100-fold" higher incidence in Tasmar users.
A feature of FH seems to be virtual destruction of the liver,
either by atrophy or necrosis. The most successful treatment
has been immediate surgical replacement (graft) of all or part
of the liver. Authorities now require informed consent by those
wishing to continue taking Tasmar, and frequency of blood tests
(to detect liver disease in general) increased from monthly to
biweekly, for at least a year. The problem with periodic blood
tests, for raised levels of the enzymes alanine aminotransferase
(ALT) or aspartate aminotransferase (AST), is that they may not
give timely warning of FH, because of its very rapid onset.
FH may be caused by a virus. Viruses specific to hepatitis are
so numerous they are named by letters of the alphabet. Suspects
mentioned include hepatitis A, B, C, D, and G, as well as the
Epstein-Barr virus that is associated with other disease. Since
the viruses are all contagious, transmissible via food, blood,
etc., it's quite possible for FH to result from liver transplant
surgery done for some other reason. FH is also associated with
some (medical) drugs other than tolcapone, such as halothane,
amiodarone, or topiramate, to name a few. But my time, facility,
and access aren't up to the task of checking out all the
possibilities. What's needed is an up-to-date review of FH and
tolcapone, preferably by a liver specialist who keeps abreast of
literature on that subject.
Now, risk by itself isn't all bad. It depends on what may be
gained. A PD patient who likes the benefits of Tasmar urgently
needs answers to these two questions, presently unknown, to
decide whether the benefits to him/her outweigh the risk:
(a) Given that FH may happen to anyone, what is the nature and
extent of the additional risk from taking Tasmar?
(b) Does the frequent blood test now required, or any other
test, reduce that risk by providing warning in time to avoid
the disaster of FH?
Until then, stay tuned. Cheers,
Joe
--
J. R. Bruman (818) 789-3694
3527 Cody Road
Sherman Oaks, CA 91403-5013
