. 2015 Oct 9;112(41):693–704. doi: 10.3238/arztebl.2015.0693

Table 4. Methotrexate treatment protocols for extrauterine pregnancy.

Protocol	Dosage, mode of administration	Timing of administration	hCG measurement	Additional administration
Single-dose	MTX 50 mg/m² BSA IM	Day 1	before treatment Day 1 Day 4 Day 7	MTX 50 mg/m² BSA, IM on Day 7: if hCG drops by <15% from day 4 to day 7
Multi-dose	MTX 1 mg/kg IM LEU 0.1 mg/kg IM	Day 1 MTX Day 2 LEU possibly Day 3 MTX Day 4 LEU possibly Day 5 MTX Day 6 LEU possibly Day 7 MTX Day 8 LEU	before treatment Day 1 Day 3 Day 5 Day 7	2nd, 3rd, or 4th dose of MTX 1mg/kg IM followed by LEU 0.1 mg/kg IM: if hCG drops by < 15% of prior hcg value

Protocol

Dosage, mode of administration

Timing of administration

hCG measurement

Additional administration

Single-dose

MTX 50 mg/m² BSA IM

Day 1

before treatment
Day 1
Day 4
Day 7

MTX 50 mg/m² BSA, IM on Day 7:

if hCG drops by <15% from day 4 to day 7

Multi-dose

MTX 1 mg/kg IM
LEU 0.1 mg/kg IM

Day 1 MTX
Day 2 LEU

possibly

Day 3 MTX
Day 4 LEU

possibly

Day 5 MTX
Day 6 LEU

possibly

Day 7 MTX
Day 8 LEU

before treatment
Day 1
Day 3
Day 5
Day 7

2nd, 3rd, or 4th dose of MTX 1mg/kg IM followed by LEU 0.1 mg/kg IM:

if hCG drops by < 15% of prior hcg value

MTX, methotrexate; LEU, leucovorin; BSA, body surface area; hCG, human chorionic gonadotropin; IM, intramuscular.

Comments: a battery of laboratory tests (complete blood count with differential, liver enzymes , creatinine, blood-group determination, antibody search test) is obligatory before treatment; the serum hCG level must be rechecked every 7 days after the last dose of MTX until it becomes normal.