Do patients with rheumatoid arthritis established on methotrexate and folic acid 5 mg daily need to continue folic acid supplements long term?
BACKGROUND
It is postulated that some aspects of methotrexate toxicity may be related to its action as an anti-folate. Folic acid (FA) is often given as an adjunct to methotrexate therapy, but there is no conclusive proof that it decreases the toxicity of methotrexate and there is a theoretical risk that it may decrease the efficacy of methotrexate.


OBJECTIVE
To look at the effect of stopping FA supplementation in UK rheumatoid arthritis (RA) patients established on methotrexate <20 mg weekly and FA 5 mg daily, to report all toxicity (including absolute changes in haematological and liver enzyme indices) and to report changes in the efficacy of methotrexate.


METHODS
In a prospective, randomized, double-blind, placebo-controlled study, 75 patients who were established on methotrexate <20 mg weekly and FA 5 mg daily were asked to stop their FA and were randomized to one of two groups: placebo or FA 5 mg daily. Patients were evaluated for treatment toxicity and efficacy before entry and then at intervals of 3 months for 1 yr.


RESULTS
Overall, 25 (33%) patients concluded the study early, eight (21%) in the group remaining on FA and 17 (46%) in the placebo group (P = 0.02). Two patients in the placebo group discontinued because of neutropenia. At 9 months there was an increased incidence of nausea in the placebo group (45 vs. 7%, P = 0.001). The placebo group had significantly lower disease activity on a few of the variables measured, but these were probably not of clinical significance.


CONCLUSIONS
It is important to continue FA supplementation over the long term in patients on methotrexate and FA in order to prevent them discontinuing treatment because of mouth ulcers or nausea and vomiting. Our data suggest that FA supplementation is also helpful in preventing neutropenia, with very little loss of efficacy of methotrexate.
Griffith
S M
SM
Department of Rheumatology, East Surrey Hospital, Surrey, UK.
Fisher
J
J
Clarke
S
S
Montgomery
B
B
Jones
P W
PW
Saklatvala
J
J
Dawes
P T
PT
Shadforth
M F
MF
Hothersall
T E
TE
Hassell
A B
AB
Hay
E M
EM
D000368:Aged; D018501:Antirheumatic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy*; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008727:Methotrexate / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome
D018501:Antirheumatic Agents; D005492:Folic Acid; D008727:Methotrexate