Neutrexin Dosage

Medically reviewed by Drugs.com. Last updated on May 2, 2022.

Generic name: trimetrexate glucuronate
Dosage form: for Injection

Caution: Neutrexin (trimetrexate glucuronate for injection) must be administered with concurrent leucovorin (leucovorin protection) to avoid potentially serious or life-threatening toxicities. Leucovorin therapy must extend for 72 hours past the last dose of Neutrexin.

Neutrexin (trimetrexate glucuronate for injection) is administered at a dose of 45 mg/m2 once daily by intravenous infusion over 60 minutes. Leucovorin must be administered daily during treatment with Neutrexin and for 72 hours past the last dose of Neutrexin. Leucovorin may be administered intravenously at a dose of 20 mg/m2 over 5 to 10 minutes every 6 hours for a total daily dose of 80 mg/m2, or orally as 4 doses of 20 mg/m2 spaced equally throughout the day. The oral dose should be rounded up to the next higher 25 mg increment. The recommended course of therapy is 21 days of Neutrexin and 24 days of leucovorin.

Neutrexin and leucovorin may alternatively be dosed on a mg/kg basis, depending on the patient’s body weight, using the conversion factors shown in the table below:

Body Weight (kg)	Neutrexin Dose (mg/kg/day)	Leucovorin Dose (mg/kg/qid)
<50	1.5	0.6
50-80	1.2	0.5
>80	1.0	0.5

Dosage Modifications

Hematologic toxicity: Neutrexin (trimetrexate glucuronate for injection) and leucovorin doses should be modified based on the worst hematologic toxicity according to the following table. If leucovorin is given orally, doses should be rounded up to the next higher 25 mg increment.

TABLE 5 DOSE MODIFICATIONS FOR HEMATOLOGIC TOXICITY
* If Grade 4 hematologic toxicity occurs prior to Day 10, Neutrexin should be discontinued. Leucovorin (40 mg/m2, q6h) should be administered for an additional 72 hours. If Grade 4 hematologic toxicity occurs at Day 10 or later, Neutrexin may be held up to 96 hours to allow counts to recover. If counts recover to Grade 3 within 96 hours, Neutrexin should be administered at a dose of 22 mg/m2 and leucovorin maintained at 40 mg/m2, q6h. When counts recover to Grade 2 toxicity, Neutrexin dose may be increased to 45 mg/m2, but the leucovorin dose should be maintained at 40 mg/m2 for the duration of treatment. If counts do not improve to ≤ Grade 3 toxicity within 96 hours, Neutrexin should be discontinued. Leucovorin at a dose of 40 mg/m2, q6h should be administered for 72 hours following the last dose of Neutrexin.
			Recommended Dosages of
Toxicity Grade	Neutrophils (Polys and Bands)	Platelets	Neutrexin	Leucovorin
1	>1000/mm3	>75,000/mm3	45 mg/m2 once daily	20 mg/m2 every 6 hours
2	750-1000/mm3	50,000-75,000/mm3	45 mg/m2 once daily	40 mg/m2 every 6 hours
3	500-749/mm3	25,000-49,999/mm3	22 mg/m2 once daily	40 mg/m2 every 6 hours
4	<500/mm3	<25,000/mm3	Day 1-9 Discontinue Day 10-21 Interrupt up to 96 hours*	40 mg/m2 every 6 hours

Hepatic toxicity: Transient elevations of transaminases and alkaline phosphatase have been observed in patients treated with Neutrexin. Interruption of treatment is advisable if transaminase levels or alkaline phosphatase levels increase to >5 times the upper limit of normal range.

Renal toxicity: Interruption of Neutrexin is advisable if serum creatinine levels increase to > 2.5 mg/dL and the elevation is considered to be secondary to Neutrexin.

Other toxicities: Interruption of treatment is advisable in patients who experience severe mucosal toxicity that interferes with oral intake. Treatment should be discontinued for fever (oral temperature ≥ 105°F/40.5°C) that cannot be controlled with antipyretics.

Leucovorin therapy must extend for 72 hours past the last dose of Neutrexin.

More about Neutrexin (trimetrexate)

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