Methotrexate

It is thought that methotrexate is the cornerstone of the therapy for the patients, who have not responded well to other NSAIDs in severe rheumatoid arthritis or psoriatic arthritis.


Action:
As this is an immunosuppressant, this may be responsible for its effectiveness in reducing arthritis which according to some experts is an autoimmune disease.

Methotrexate slows the decay within moving joints, which may be due to the inhibition of thymidylate synthetase and some other related enzymes.

Pharmacokinetics:
The drug is found to be absorbed about 65%-75% after oral administration. Its serum half life is about 6-9 hours.

It has been found that methotrexate shows response usually sooner than the other agents i.e. it may be within 3 to 6 weeks of treatment.

Dosage:
Small doses are effective for the treatment of Arthritis than those needed for the treatment of cancer as this drug is also useful for the treatment of cancer. The dose is reduced to once a week administration.

Adverse Effects:
In small doses it may cause mucosal ulceration and nausea. Some of the following adverse effects may also be seen:

1. Cytopenia

2. Liver cirrhosis (it is particularly dose related)

3. Pneumonia like syndrome (hypersensitivity lung reaction)