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DMARDs-In Depth-Plaquenil & Methotrexate
DMARDs-In depth
Hydroxychloroquine (Plaquenil)
Plaquenil was originally
intended to treat malaria and by some fluke of luck it was discovered
that it had positive benefits for some forms of arthritis. Usually used
to treat mild cases, its side effects are usually minimal for most
people.
Plaquenil may not fall into the DMARD category by definition. Although
it does relieve pain and inflammation at least one study has shown that
it does not slow the disease process. In fact, in this study joint
erosions after two years of plaquenil therapy were no different than if
the person had not taken DMARDs at all. But we must keep in mind that
this was one study.
Plaquenil is one of the least toxic DMARDs and less costly to monitor.
The major toxicity problem of plaquenil is retinal damage, which can
lead to visual impairment. This problem is very rare, and can be
reversed if caught early. The American College of Rheumatology
recommends complete eye exams and central field testing be performed
every 6-12 months. People with impaired kidney function or those who
have been on the drug for over 10 years may require more frequent
testing.
As with many other DMARDs, it can take 3-6 months before the full
benefit of the medication is felt. Patience is required!
Plaquenil may aggravate psoriasis in those with psoriatic arthritis and
poses a small risk of birth defects when taken by a pregnant woman. The
most common side effect is gastrointestinal complaints.
Methotrexate (Rheumatrex) (MTX)
Methotrexate is probably the most widely prescribed DMARD. Originally
used as a chemotherapy agent, the mere suggestion of chemo drug strikes
fear in many a new arthritis patient. It is very important to realize
that when used for chemotherapy methotrexate is given in much higher
doses than used for inflammatory arthritis and the side effects are much
milder.
Methotrexate acts on arthritis in two ways, as an Immunosuppressant to
calm down an over active immune system and as an anti inflammatory
agent. Despite its long list of potential side effects, methotrexate
actually has an impressive track record for long term use. It is not
uncommon to be taking MTX along with one or two other DMARDs.
Methotrexate seems to work longer and more effectively as part of a
combination. The combination may also allow a person to take a lower
dose of MTX, thereby decreasing some of the side effects,
The most serious toxicities of MTX include hepatic fibrosis and
cirrhosis, pneumonitis, and an increased risk of infection. These
problems are possible but rarely occur. Years ago liver biopsies were
considered an effective monitoring tool for those on MTX. Thank goodness
that thinking has changed, The American College of Rheumatology does not
recommend routine biopsies unless the person has an underlying liver
problem. Liver biopsies may be needed if liver specific lab works
becomes abnormal during the treatment. Those at risk for liver problems
related to MTX include diabetics with existing liver or kidney problems,
alcoholics, those who are obese, the elderly, and those with psoriasis.
Lung disease occurs in up to 5% of people who take methotrexate. There
are five risk factors for methotrexate-induced lung diseases: age,
diabetes, existing rheumatoid involvement in the lung, protein in the
urine, and previous use of other DMARDs. Persons with any of these
factors should pay careful attention and report any abnormal lung
symptoms immediately.
Liver function studies, renal function tests, and blood counts should be
done routinely when on MTX. The American College of Rheumatology
recommends that most of these blood tests be done every 4-8 weeks.
Other more common side effects of methotrexate therapy include GI
disturbances, mouth sores, and mild hair loss. If these side effects
occur, the intensity may be lessen by taking folic acid.
MTX can cause birth defects when taken by either parent. Most experts
recommend waiting at least 3 months after taking the last dose of MTX
before attempting to conceive. If you are taking MTX and suspect that
you or your partner is pregnant, please contact your doctor right away.
There have been a few studies that show an increase risk of lymphomas in
some people taking methotrexate; however, the disease appears to go into
remission when the drug is stopped. Most studies have found no
significant risk for cancer associated with mtx.
Sources:
Guidelines for monitoring drug therapy in rheumatoid arthritis. American
College of Rheumatology Ad Hoc Committee on Clinical Guidelines.
Rheumatiod Arthritis (Comprehensive Version), Well-Connected, Copyright
? Nidus Information Services 2000
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