Regular monitoring tests can help reduce your risk of harmful DMARD side effects.
Just as your doctor uses blood tests and imaging tests to monitor your arthritis, your doctor may also order periodic tests to check for any negative effects of the medicines you take.
Certain disease-modifying antirheumatic drugs (DMARDs) can harm your organs and tissues, including your liver, kidney, blood and eyes. Regular monitoring is the best way to detect small problems early and keep them from becoming big problems later.
Following are tests your doctor will likely order if you are prescribed a DMARD. Be aware that your doctor may order tests that are not mentioned here or may order these same tests for drugs that are not mentioned here. More routine checks, such as weight and blood pressure, may also give your doctor important clues about how your medication is affecting you.
Your doctor may order tests more frequently than noted – particularly if you are taking more than one drug. Or she may order them less frequently, particularly if you have been on the same DMARD for quite a while and your test results have remained stable.
Regardless of the tests your doctor orders or their frequency, it is important to keep up with the monitoring your doctor recommends. This will help her maximize the benefits of your DMARD treatment, while helping to protect you from the less desirable effects of these medications.
Complete Blood Count (CBC)
Who needs it: people taking azathioprine, cyclosporine, leflunomide, methotrexate, mycophenolate or sulfasalazine.
Why you need it: to check for changes in levels of different blood components. These components include white blood cells, which fight infection and other invaders; red blood cells, which carry oxygen to your body’s tissues; platelets, which enable the blood to clot; and hemoglobin, the protein in red blood cells that carries oxygen. Hematocrit, the ratio of red blood cells to plasma (or fluid) in your blood, will also be checked. In one potentially serious side effect of DMARDs, all blood cell counts are reduced. This condition, called pancytopenia, can cause weakness, fatigue, heart failure and sepsis (toxins in the blood from overwhelming infection).
How often you need it: this will depend on the specific drug(s) you are taking and other factors, such as existing medical problems and how long you have been taking the medicines. Frequency may range from weekly for someone just starting azathioprine to every six months for someone taking methotrexate.
Liver Function Tests
Who needs it: people taking azathioprine, cyclosporine, leflunomide, methotrexate or sulfasalazine.
Why you need it: to check blood levels of enzymes and proteins that measure how well your liver is working or indicate liver damage. These include albumin, a protein that keeps fluid from the blood from leaking out into the tissues; bilirubin, a yellowish pigment found in bile, which is made by the liver; and alanine transaminase (ALT), a liver enzyme that is released into the blood when the liver is damaged.
How often you need it: this will depend on a number of factors including the drug (s) you are taking, how long you have been taking them and other medical problems you may have. In general, frequency ranges from once weekly for someone beginning azathioprine to every three months for someone taking sulfasalazine.
Kidney Function Test
Who needs it: People taking cyclosporine or methotrexate.
Why you need it: to check for a reduction in kidney function. Common tests for kidney function include the BUN (blood urea nitrogen) and creatinine tests. Each measures levels of a bodily waste product in the blood. Urea nitrogen is formed when protein breaks down. Creatinine is produced by the muscles from the breakdown of the compound creatine. Both of these are normally excreted through the kidneys. Thus high levels indicate the kidneys are not working efficiently. Sometimes doctors order tests to measure creatinine in the urine or tests to compare levels in the urine and blood.
How often you need it: usually every two weeks to start and then reduced to monthly.
Who needs it: people taking hydroxychloroquine.
Why you need it: to check for blurred vision or other problems related to hydroxychloroquine use.
How often you need it: once a year or as recommended by your doctor.