DMARDs-In Depth-Plaquenil Methotrexate

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