Initial dose: 50 mg per square meter of body surface area, given IM.
No leucovorin is given.
Contraindications to methotrexate therapy:
(1) thrombocytopenia
(2) leukopenia
(3) elevated serum liver function tests
(4) elevated serum creatinine
Serum monitoring of beta-HCG is done:
(1) on day 4
(2) on day 7
(3) weekly until serum beta-HCG is no longer detectable
A repeat dose is given if:
(1) the decline in serum beta-HCG between days 4 and 7 is < 15%, with the serum level on day 7 > 0.85 * (serum level on day 4)
(2) the serum level of beta HCG after day 7 plateaus or rises
(3) weekly serum measurements of beta-HCG fail to decline
NOTE: I assume that only a single repeat dose is given with this protocol.
Surgery is performed if:
(1) evidence of tubal rupture (clinical, ultrasonography, other)
(2) additional therapy required but the patient has a contraindication to further methotrexate therapy
(3) increasing pain
Patient instructions:
(1) avoid alcohol (because of potential liver injury)
(2) drink > 1,500 mL of liquid per day
(3) no sexual intercourse or pelvic examination until resolved
(4) pregnancy should be delayed for >= 3 months because of the teratogenic effect of methotrexate
