Dosage/Direction for Use
Intravenous As a cytoprotective agent in chemotherapy Adult: Initially, 910 mg/m2 once daily via infusion over 15 min, starting 30 min prior to chemotherapy. Subsequent doses reduced to 740 mg/m2 if patient is unable to tolerate the full dose. For cisplatin doses <100 mg/m2: 740 mg/m2. Reconstitution: Add 9.7 mL of sterile NaCl 0.9% inj to a 500 mg vial to prepare a 10 mL soln containing 50 mg/mL. For use prior to chemotherapy, dilute further in sterile NaCl 0.9% to a final concentration of 5-40 mg/mL. Incompatibility: Y-site admin: Incompatible w/ aciclovir, amphotericin B, cefoperazone, chlorpromazine, cisplatin, ganciclovir, hydroxyzine, miconazole, minocycline, prochlorperazine edisilate. Syringe: Ceftriaxone. Intravenous Prophylaxis of xerostomia in patients undergoing radiotherapy for head and neck cancer Adult: 200 mg/m2 once daily via infusion over 3 min, starting w/in 15-30 min prior to radiotherapy. Reconstitution: Add 9.7 mL of sterile NaCl 0.9% inj to a 500 mg vial to prepare a 10 mL soln containing 50 mg/mL. For use prior to chemotherapy, dilute further in sterile NaCl 0.9% to a final concentration of 5-40 mg/mL. Incompatibility: Y-site admin: Incompatible w/ aciclovir, amphotericin B, cefoperazone, chlorpromazine, cisplatin, ganciclovir, hydroxyzine, miconazole, minocycline, prochlorperazine edisilate. Syringe: Ceftriaxone. |
Contraindications
Hypotension, dehydration. Lactation.
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Special Precautions
Patient w/ CV or cerebrovascular disease (e.g. ischaemic heart disease, arrhythmias, CHF, history of stroke or transient ischaemic attack). Renal impairment. Pregnancy. Monitoring Parameters Monitor BP every 5 min during infusion (prior to chemotherapy) or at least before and immediately after infusion (prior to radiotherapy); and thereafter as clinically indicated. Monitor serum Ca levels in patients at risk of hypocalcaemia. Evaluate for cutaneous reactions prior to each dose.
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Adverse Reactions
Reduction in BP; nausea, vomiting; flushing, chills, malaise, fever, dizziness, somnolence, hiccups, sneezing, cough; rash, pruritus, urticaria, chest tightness, laryngeal oedema; severe acute allergic reaction; pain, inflammation, bruising, phlebitis, and local swelling at inj site. Rarely, loss of consciousness, tachycardia, bradycardia, arrhythmias (e.g. atrial fibrillation/flutter, supraventricular tachycardia), chest pain, myocardial ischaemia, MI, cardiac and resp arrest, convulsions, dyspnoea, apnoea, hypoxia, renal failure, hypocalcaemia, transient HTN.
Potentially Fatal: Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme, exfoliative dermatitis, bullous toxicity. |
Overdosage
Symptoms: Hypotension, nausea, vomiting, hypocalcaemia. Management: Supportive treatment.
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Drug Interactions
May potentiate hypotension w/ antihypertensive medications.
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Action
Amifostine, an aminothiol prodrug, is dephosphorylated by alkaline phosphatase in tissues into an active free thiol metabolite, WR-1065, which protects noncancerous cells against the toxic effects of antineoplastics and ionising radiation. WR-1065 binds and detoxify reactive metabolites and acts as scavenger of free radicals.
Distribution: Distributed into normal tissues w/ high concentrations in bone marrow, GI mucosa, skin, liver and salivary glands (active metabolite). Volume of distribution: 3.5L. Plasma protein binding: 4%. Metabolism: Metabolised in the liver by alkaline phosphatase via dephosphorylation to the active metabolite, WR-1065; then further metabolised to a less active disulfide metabolite, WR-33278. Excretion: Via urine (as metabolites). Elimination half-life: <10 min. |
Storage
Intravenous: Store between 20-25°C. Reconstituted soln: Store at 25°C (stable for 5 hr) or 2-8°C (stable for 24 hr).
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CIMS Class
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ATC Classification
V03AF05 - amifostine ; Belongs to the class of detoxifying agents used in antineoplastic treatment.
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