The mycophenolic acid (MPA) test is ordered to measure the amount of drug in the blood. Unlike other immunosuppressant drugs, the therapeutic range for MPA has not yet been established, and the physician may order levels to monitor drug interaction with other immunosuppressants in combination therapy or to correlate with clinical symptoms and side effects.

If someone is taking mycophenolate in addition to cyclosporine or tacrolimus, then both MPA and the other immunosuppressant concentrations will be measured.

Since mycophenolic acid can lower white blood cell counts and cause anemia, a complete blood count (CBC) will frequently be ordered along with the mycophenolic acid test to evaluate the body’s blood cell status. Other tests may also be periodically ordered to evaluate organ function as MPA levels can be affected by changes in kidney and liver function.

Mycophenolic acid test and CBC are ordered frequently at the start of therapy and then at intervals for as long as the patient is taking mycophenolate. The MPA test may be performed whenever there is a change in dosage, a change in other medications that the patient is taking, or whenever a patient has symptoms that suggest side effects, toxicity, or organ rejection.

Concentrations that are too high may cause toxicity. Concentrations that are too low may lead to rejection of the transplanted organ. Since the therapeutic range is not yet fully established, doctors will rely on the patient’s clinical signs and their own expertise in addition to drug levels to help guide treatment and adjust dosage if necessary.

If the person is also taking another immunosuppressant and/or other medications, then all of them will need to be in balance. Patients should work closely with their doctor and transplant team.

Mycophenolic acid levels can be affected by other medications. Drugs that reduce MPA concentrations include antacids and cholestyramine. Drugs that can increase MPA include ganciclovir, probenecid, and acyclovir. Herbal supplements such as Echinacea, Cat’s Claw, and St. John’s wort should be avoided while taking mycophenolate.

MPA can decrease the effectiveness of oral contraceptives, and has been linked with first trimester miscarriages and congenital birth defects. Women should not become pregnant while taking mycophenolate and should not breastfeed. Two forms of birth control are recommended, as is a pregnancy test prior to the start of the medication. Patients who become pregnant should talk to their doctor about the associated risks.

Those who are taking mycophenolate should talk to their doctor before getting any vaccines.

Patients may have side effects and experience complications such as infections and slow healing even when taking mycophenolate properly. Side effects may include:

Anemia

Constipation

Diarrhea

Nausea

Insomnia

Fatigue

Muscle pain

Stomach pain

Dizziness

Tremors