Misuse of higher dose of Vioxx (rofecoxib) is common

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Misuse of higher dose of rofecoxib is common

Rheumawire

Jul 15, 2004

Nainggolan

Nashville, TN - The 50-mg dose of rofecoxib (Vioxx, Merck & Co)which is

recommended for use in acute pain onlyis increasingly being prescribed

long term for patients with arthritis and other chronic conditions, with

a subsequent increased risk of adverse effects, US researchers report in

the June 2004 issue of Pharmacoepidemiology and Drug Safety [1].

Lead researcher Dr Marie R (Vanderbilt University, Nashville,

TN) believes the higher dose of rofecoxib should be abandoned altogether

or at least restricted: " I personally think that the best thing would be

to get rid of the 50-mg dose or sell it only in packages of 5. "

" Rofecoxib is unusual among nonsteroidal anti-inflammatory drugs

[NSAIDs], in that the licensed dose for acute pain is double the maximum

dose recommended for chronic use, " and colleagues explain. (In

the US, rofecoxib is licensed for chronic use for osteoarthritis at

doses of 12.5 mg and 25 mg and for acute pain at doses to 50 mg.)

The researchers counted the number of prescriptions for NSAIDs,

including ibuprofen, naproxen, celecoxib (Celebrex, Pfizer), and

rofecoxib given to participants aged over 49 in Tennessee's Medicaid

program, called TennCare.

Of 40 000 participants who had prescriptions for any NSAID as of July 1,

2001, 46% were prescribed the COX-2 inhibitors, either rofecoxib or

celecoxib, and 37% were given ibuprofen or naproxen. Rofecoxib was

prescribed at doses greater than recommended for chronic use for a

substantial number of users, 17%, compared with less than 1% of

ibuprofen and celecoxib users. More than 1000 of the 9841 people taking

rofecoxib were " high-dose " users, with 30-day supplies of 50-mg pills.

This is despite the fact that the 50-mg dose has not been shown to be

more effective than lower doses of the drug in relieving chronic pain

and has been linked to an increased risk of hypertension, edema, and

myocardial infarctions, say the researchers.

" The use of the 50-mg dose is likely the result of physicians using the

doses approved for acute pain and chronic arthritis interchangeably, a

perception that may have arisen in part from the fact that the

best-known clinical trial of rofecoxib, the VIGOR study, used a 50-mg

dose, " the researchers note.

" We think that the rationale is that if 25 mg works well, then 50 mg is

going to work better, " says . " But when you look at the scant

data that are out there for chronic pain, there's been no study that

shows that 50 is better than 25. "

" This is really common with a lot of drugs, that there's a ceiling on

the effective dose. . . . But unfortunately, there's usually not a

ceiling on the side effects, " adds.

" Since the 50-mg dose has clinically significant undesirable effects and

has not been shown to be more effective than the lower doses, chronic

use of high-dose rofecoxib should be discouraged, " the researchers say.

They add that a follow-up COX-2 inhibitor, valdecoxib (Bextra, Pfizer),

is " similar " to rofecoxib in that a 10-mg dose is the maximum

recommended for arthritis, whereas a 4-fold higher dose, 20 mg twice

daily, is recommended for dysmenorrhea. " Further investigation of

potential adverse effects of chronic use of these high doses of COX-2

inhibitors intended for short-term indications is warranted, " they

conclude.

Source

MR, Stein CM, Graham DJ, et al. High frequency

of use of rofecoxib at greater than recommended doses: cause for

concern. Pharmacoepidemiol Drug Saf 2004; 13:339-343.

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org