AMIFOSTINE

Medical Diagnosis and Drugs, Medications

AMIFOSTINE
(am-i-fos'teen)
Ethyol
Classifications: cytoprotective agent;
Therapeutic: cytoprotective agent
Pregnancy Category: C

Availability

500 mg vial

Action

Amifostine reduces cytotoxic damage induced by radiation or antineoplastic agents in well-oxygenated cells. Protective effects appear to be mediated by the formation of a metabolite of amifostine that removes free radicals from normal cells exposed to cisplatin.

Therapeutic Effect

Amifostine is cytoprotective in the kidney, bone marrow, and GI mucosa, but not in the brain or spinal cord. The cytoprotection results in decreased myelosuppression and peripheral neuropathy.

Uses

Reduction of the cumulative renal toxicity associated with cisplatin, xerostomia.

Unlabeled Uses

Reduction of paclitaxel toxicity.

Contraindications

Sensitivity to aminothiol compounds or mannitol, patients with potentially curable malignancies, hypotensive patients or those who are dehydrated, lactation; exfoliated dermatitis; pregnancy (category C).

Cautious Use

Patients at risk for hypocalcemia, cardiovascular disease (i.e., arrhythmias, CHF, TIA, CVA); radiation therapy; renal disease.

Route & Dosage

Renal Protection
Adult: IV 910 mg/m² once daily prior to chemotherapy

Reduction of Xerostomia
Adult: IV 200 mg/m² prior to radiation therapy

Administration

Intravenous

Give antiemetics, adequately hydrate, and defer antihypertensives for 24 h prior to administration.

PREPARE: IV Infusion: Reconstitute by adding 9.7 mL of NS injection to a single-dose vial to yield 50 mg/mL. May be further diluted with NS to a concentration as low as 5 mg/mL.

ADMINISTER: IV Infusion: Infuse over no more than 15 min, beginning 30 min before chemotherapy; place patient in supine position prior to and during infusion. For xerostomia, infuse over 3 min; begin 15–30 min before radiation.

INCOMPATIBILITIES Solution/additive: Do not mix with any solutions other than NS. Y-site: Acyclovir, amphotericin B, chlorpromazine, cisplatin, ganciclovir, hydroxyzine, prochlorperazine.

Store reconstituted solution at 15°–30° C (59°–86° F) for 5 h or refrigerate up to 24 h.

Adverse Effects (≥1%)

CV: Transient reduction in blood pressure. GI: Nausea, vomiting. Other: Infusion reactions (flushing, feeling of warmth or coldness, chills, dizziness, somnolence, hiccups, sneezing), hypocalcemia, hypersensitivity reactions.

Interactions

Drug: ANTIHYPERTENSIVES could cause or potentiate hypotension.

Pharmacokinetics

Onset: 5–8 min. Metabolism: In liver to active free thiol metabolite. Elimination: Renally excreted. Half-Life: 8 min.

Nursing Implications

Assessment & Drug Effects

Monitor for S&S of hypocalcemia and fluid balance if vomiting is significant.
Monitor BP every 5 min during infusion. Stop infusion if systolic BP drops significantly from baseline (e.g., baseline[drop]: <100[20], 100–119[25], 120–139[30], 140–179[40], >180[50]) and place patient flat with legs raised. Restart infusion if BP returns to normal in 5 min.

Patient & Family Education

Know and understand adverse effects.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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