Neoplastic disease
Adult: > 18 yr: Usually in combination with folinic acid rescue, 8 mg/m2 daily as infusion over 60-90 min for 5 days at 3 wk intervals or 150-220 mg/m2 as infusion over 60-90 min, every 28 days.
Intravenous
Pneumocystis (carinii) jirovecii pneumonia
Adult: >18yr: 45 mg/m2 infusion over 60-90 min once daily for 21 days, in association with folinic acid rescue for 24 days; folinic acid may be given as IV (over 5-10 minutes) or orally at 20 mg/m2 every 6 hr (total daily dose of 80 mg/m2). Alternatively, trimetrexate dose may be given based on patient's weight. < 50 kg: trimetrexate 1.5 mg/kg daily with folinic acid 0.6 mg/kg 4 times daily; 50-80 kg: trimetrexate 1.2 mg/kg daily with folinic acid 0.5 mg/kg 4 times daily; > 80 kg: trimetrexate 1 mg/kg daily with folinic acid 0.5 mg/kg 4 times daily; trimetrexate and folinic acid to be given for 21 days and 24 days respectively. See lit for dosage adjustment of trimetrexate and folinic acid based on neutrophil and platelet counts.