INFUGEM

Clinical safety rating: caution

Comprehensive clinical and safety monograph for INFUGEM (INFUGEM).

How it works

Gemcitabine is a nucleoside analog that inhibits DNA synthesis by replacing cytidine during DNA replication, leading to chain termination and apoptosis. It targets ribonucleotide reductase (RR), reducing deoxynucleotide pools, and incorporates into DNA, inhibiting polymerase activity.

What the body does with it

Metabolism	Primarily metabolized by deamination via cytidine deaminase in the liver, kidneys, and plasma to the inactive metabolite 2',2'-difluorodeoxyuridine (dFdU). Also phosphorylated intracellularly to active diphosphate (dFdCDP) and triphosphate (dFdCTP) forms. Minimal CYP450 involvement.
Excretion	Primarily renal (92-96% as unchanged drug and metabolites, with approximately 10% as unchanged gemcitabine). Fecal excretion is minimal (<5%).
Half-life	Short initial phase (t1/2α 3-15 min); terminal elimination half-life (t1/2β) 42-94 min (mean ~65 min) dependent on infusion duration and sex. For prolonged infusion (>70 min), half-life extends due to saturable elimination.
Protein binding	<10% bound to plasma proteins (negligible, primarily to albumin).
Volume of Distribution	50 L/m² (range 10-80 L/m²) in adults; equivalent to approximately 1.2 L/kg (assuming 1.73 m² BSA and 70 kg). Extensive distribution into tissues, including solid tumors.
Bioavailability	Not orally bioavailable (0% due to extensive first-pass metabolism and poor absorption); only intravenous administration (100% bioavailability IV).
Onset of Action	Onset of antineoplastic effect occurs after multiple doses; cell cycle phase-specific activity (S-phase) requires drug exposure time. No immediate clinical effect.
Duration of Action	Duration of action is schedule-dependent; cytotoxic effect persists for hours post-infusion due to intracellular triphosphate accumulation with a terminal half-life of 35-72 hours in cells. Clinical effects are cumulative over cycles.

Classification & Brands

Dosing & administration

1000 mg/m² intravenously over 30 minutes on days 1 and 8 of a 21-day cycle.

Dosage form	SOLUTION
Renal impairment	For GFR 30-80 mL/min: no adjustment. For GFR <30 mL/min: contraindicated.
Liver impairment	Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 25%. Child-Pugh C: avoid use.
Pediatric use	Not established; safety and efficacy in children have not been studied.
Geriatric use	No specific dose adjustments; monitor renal function and hematologic toxicity closely.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for INFUGEM (INFUGEM).

Breastfeeding	No data on excretion into human milk. M/P ratio unknown. Given potential for serious adverse reactions in nursing infants, breastfeeding is not recommended during therapy and for at least 1 week after last dose.
Teratogenic Risk	INFUGEM (gemcitabine) is classified as FDA Pregnancy Category D. There is evidence of fetal harm in the first trimester; malformations may occur. In second and third trimesters, risk of growth restriction, preterm birth, and neonatal myelosuppression exists. Use only if benefit outweighs risk.

Warnings & precautions

■ FDA Black Box Warning

Boxed Warning: Gemcitabine can cause severe and life-threatening infusion-related reactions (including hypotension, dyspnea, and bronchospasm), and should be used with caution. Administration should be immediately discontinued if severe reaction occurs. Additionally, gemcitabine can cause myelosuppression (neutropenia, thrombocytopenia, anemia).

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to gemcitabine or any component of the formulation","Severe pre-existing myelosuppression (absolute neutrophil count < 500/mm³, platelet count < 50,000/mm³)","Concurrent live vaccines"]

Clinical Precautions

Precautions

["Myelosuppression (dose-limiting toxicity; monitor CBCs)","Infusion-related reactions (may require premedication)","Pulmonary toxicity (including pneumonitis, pulmonary edema)","Hepatotoxicity (elevated liver enzymes)","Renal toxicity (hemolytic uremic syndrome reported)","Cardiovascular effects (arrhythmias, myocardial infarction)","Posterior reversible encephalopathy syndrome (PRES)","Radiation sensitization (increased toxicity with concurrent radiotherapy)","Fetal harm if used during pregnancy"]

Clinical Tips & Counseling

Drug interactions

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INFUGEM

Clinical safety rating: caution

Comprehensive clinical and safety monograph for INFUGEM (INFUGEM).

How it works

What the body does with it

Metabolism	Primarily metabolized by deamination via cytidine deaminase in the liver, kidneys, and plasma to the inactive metabolite 2',2'-difluorodeoxyuridine (dFdU). Also phosphorylated intracellularly to active diphosphate (dFdCDP) and triphosphate (dFdCTP) forms. Minimal CYP450 involvement.
Excretion	Primarily renal (92-96% as unchanged drug and metabolites, with approximately 10% as unchanged gemcitabine). Fecal excretion is minimal (<5%).
Half-life	Short initial phase (t1/2α 3-15 min); terminal elimination half-life (t1/2β) 42-94 min (mean ~65 min) dependent on infusion duration and sex. For prolonged infusion (>70 min), half-life extends due to saturable elimination.
Protein binding	<10% bound to plasma proteins (negligible, primarily to albumin).
Volume of Distribution	50 L/m² (range 10-80 L/m²) in adults; equivalent to approximately 1.2 L/kg (assuming 1.73 m² BSA and 70 kg). Extensive distribution into tissues, including solid tumors.
Bioavailability	Not orally bioavailable (0% due to extensive first-pass metabolism and poor absorption); only intravenous administration (100% bioavailability IV).
Onset of Action	Onset of antineoplastic effect occurs after multiple doses; cell cycle phase-specific activity (S-phase) requires drug exposure time. No immediate clinical effect.
Duration of Action	Duration of action is schedule-dependent; cytotoxic effect persists for hours post-infusion due to intracellular triphosphate accumulation with a terminal half-life of 35-72 hours in cells. Clinical effects are cumulative over cycles.

Classification & Brands

Dosing & administration

1000 mg/m² intravenously over 30 minutes on days 1 and 8 of a 21-day cycle.

Dosage form	SOLUTION
Renal impairment	For GFR 30-80 mL/min: no adjustment. For GFR <30 mL/min: contraindicated.
Liver impairment	Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 25%. Child-Pugh C: avoid use.
Pediatric use	Not established; safety and efficacy in children have not been studied.
Geriatric use	No specific dose adjustments; monitor renal function and hematologic toxicity closely.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for INFUGEM (INFUGEM).

Breastfeeding	No data on excretion into human milk. M/P ratio unknown. Given potential for serious adverse reactions in nursing infants, breastfeeding is not recommended during therapy and for at least 1 week after last dose.
Teratogenic Risk	INFUGEM (gemcitabine) is classified as FDA Pregnancy Category D. There is evidence of fetal harm in the first trimester; malformations may occur. In second and third trimesters, risk of growth restriction, preterm birth, and neonatal myelosuppression exists. Use only if benefit outweighs risk.