Methotrexate can heighten the effects of sunburn to produce significant erythroderma, something Dr. Weinblatt described as “cooked lobster syndrome.” He advises his patients taking methotrexate to use caution in the sun and to avoid tanning salons.
Methotrexate hematologic toxicity is avoidable. The drug is cleared by the kidneys, so patients with renal insufficiency, folate deficiencies or infections; those taking daily sulfamethoxazole; or those who have made dosing errors may be at risk. “Dialysis is an absolute contraindication!” Dr. Weinblatt said. One dose of methotrexate for a patient on dialysis may be associated with bone marrow toxicity and death.
The drug is an abortifacient and teratogenic, Dr. Weinblatt said. Female RA patients who wish to conceive should stop using methotrexate for at least one to two menstrual cycles before attempting conceiving. The package insert suggests that males should wait a minimum of three months after stopping therapy before attempting conception, but there are few data to support this claim.
As for potential hepatotoxicity, RA patients taking methotrexate may vary widely in their alcohol tolerance, said Dr. Kremer. He advises patients to limit their alcohol to one drink per day. Liver function tests every four to eight weeks may help ensure that the liver is healthy in patients without elevated AST levels. “Don’t allow your patient’s transaminase levels to remain elevated. Adjust the methotrexate dose to get the AST level to normal and the liver will be happy.” Risk factors for elevated transaminases include obesity, untreated high cholesterol, pretherapy LFT elevations, use of some biologic agents and lack of folic acid supplementation.
In RA patients who also have diabetes mellitus, higher insulin levels correlate with higher lung toxicity levels, he said. Stop methotrexate in cases of patients with pulmonary infiltrates, but lower the dose and observe patients with a new, nonproductive cough. Productive, persistent coughs may be a bigger concern, and if the patient does not respond to the lower dose, stop methotrexate, he said.
Although some RA patients simply cannot tolerate the treatment, “methotrexate is likely to remain the initial drug of choice for RA for years to come,” said Dr. Kremer. “It is cost effective and inexpensive.”
Susan Bernstein is a freelance medical journalist based in Atlanta.
Second Chance
If you missed this session, it’s not too late. Catch it on SessionSelect.
