Methotrexate

Question 1

side effects of MTX

Answer 1

The most important side effects of MTX include pancytopenia and hepatotoxicity
Liver fibrosis
Photosensitivity
GI intolerance
side effects include accelerated rheumatoid (cutaneous) nodulosis and
reversible lymphoproliferative disorders.
When used in very high doses, MTX may cause reversible oligospermia.

Question 2

MTX mechanism of action

Answer 2

MTX competitively inhibits DHFR, although this inhibition can be at least partially reduced by
concomitant folic acid administration.

MTX inhibits DNA synthesis in immunologically active cells.

MTX decreases inflammation through other mechanisms as well. For example. by inhibiting otherr enzymes with end result increased adenosiine, potent anti inflammatory , andcdecreased levels of pro-inflammatory mediators.

Question 3

MTX mechanism of action

Answer 3

MTX competitively inhibits DHFR, although this inhibition can be at least partially reduced by
concomitant folic acid administration.

MTX inhibits DNA synthesis in immunologically active cells.

MTX decreases inflammation through other mechanisms as well. For example. by inhibiting otherr enzymes with end result increased adenosiine, potent anti inflammatory , andcdecreased levels of pro-inflammatory mediators.

Question 4

After discontinuing MTX,

Women and men should wait –‐———- before attempting to become pregnant

Answer 4

Women :
After discontinuing MTX, wait at least one ovulatory cycle before attempting to become pregnant,

Men :
After discontinuing MTX, wait 3 months before attempting to have partner become pregnant

Question 5

MTX therapy indications

Answer 5

1) Bullous pemphigoid -- 
          in the elderly, monotherapy with weekly MTX is an option for the treatment of bullous pemphigoid.
2) Cutaneous T- cell lymphoma 
3) Cutaneous LE 
4) Dermato- myositis 
5)Langerhans cell histiocytosis 
6)Lymphomatoid papulosis 
7)Palmoplantar pustulosis 
8) Pityriasis rubra pilaris 
9)Pityriasis lichenoides et varioliformis acuta 
10) Psoriasis*  FDA
11)Systemic sclerosis

Question 6

Recommended follow up monitoring

Answer 6

CBC with PLT and AST/ALT after initial 2.5-5 mg test dose

CBC with PLT and AST/ALT every week for 2-4 weeks and after each dose escalation,
then

monthly for 2-4 months, and then every 3-4 months, if stable

BUN and serum creatinine every 6-12 months

See text for discussion of serum markers and non- invasive imaging studies used to assess
hepatic fibrosis