Levoleucovorin Calcium

INTRODUCTION

Indications

Used as “rescue” following high-dose methotrexate treatment of osteosarcoma. Decreases toxicity which may follow impaired methotrexate elimination or unintended toxicity of other folic acid antagonists.

Action

The reduced form of folic acid that serves as a cofactor in the synthesis of DNA and RNA; does not require dihydrofolate reductase for activity. Therapeutic Effects: Reversal of toxic effects of folic acid antagonists, including methotrexate, that inhibit dihydrofolate reductase.

Adverse Reactions/Side Effects

(all patients also received methotrexate)

CNS: confusion. Resp: dyspnea. GI: nausea, stomatitis, vomiting, altered taste, diarrhea, dyspepsia. Derm: dermatitis. GU: abnormal renal function. Neuro: neuropathy. Misc: allergic reactions.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Monitor signs of allergic reactions, including pulmonary symptoms (tightness in the throat and chest, wheezing, cough, dyspnea) or skin reactions (rash, pruritus, urticaria). Notify physician or nursing staff immediately if these reactions occur.

• Watch for signs of kidney dysfunction, including hematuria, increased frequency, cloudy urine, and decreased urine output. Report these signs to the physician.

• Monitor signs of peripheral neuropathy (numbness, tingling). Perform objective tests (nerve conduction, monofilaments) to document any neuropathic changes.

Interventions

• For patients who are medically able to begin exercise, implement appropriate resistive exercises and aerobic training to maintain muscle strength and aerobic capacity during cancer chemotherapy or to help restore function after chemotherapy or toxicity from other drugs.

Patient/Client-Related Instruction

• Instruct patient and family/caregivers to report any bothersome side effects such as severe or prolonged confusion, dermatitis, or GI problems (indigestion, nausea, vomiting, diarrhea, altered taste, inflammation in/around the mouth).

Pharmacokinetics

Absorption: IV administration results on complete bioavailability.

Distribution: Transported actively and passively across cell membranes; enters CSF.

Metabolism and Excretion: Extensively converted to tetrahydrofolic derivatives.

Half-life: Total tetrahydrofolic acid—5.1 hr.

Contraindications/Precautions

Contraindicated in: Hypersensitivity to folic acid or folinic acid.

Use Cautiously in: Concurrent use of anticonvulsants; may increase risk of seizures; OB: Use in pregnancy only if clearly needed, use cautiously during lactation; Pedi: Has been used safely in pediatric patients.

Interactions

Drug-Drug: ↑ risk of toxicity from fluorouracil. May ↓ effectiveness of phenobarbital, phenytoin, or primidone leading to ↑ risk of seizures. May ↓ effectiveness of trimethoprim-sulfamethoxazole...