ALOXI
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ALOXI (ALOXI).
Selective serotonin 5-HT3 receptor antagonist; blocks serotonin binding at 5-HT3 receptors in the chemoreceptor trigger zone and gastrointestinal tract, preventing nausea and vomiting.
| Metabolism | Hepatic metabolism primarily via CYP1A2, CYP2D6, and CYP3A4; approximately 50% of the dose undergoes first-pass metabolism. |
| Excretion | Renal (approximately 50% unchanged drug), biliary/fecal (approximately 35% as metabolites). Total clearance is 160 ± 38 mL/min. |
| Half-life | Terminal elimination half-life is approximately 40 hours (range 33–45 hours) in adults, allowing once-daily dosing for prevention of chemotherapy-induced nausea and vomiting. |
| Protein binding | Approximately 62% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Volume of distribution is approximately 8.3 L/kg (range 5.7–10.5 L/kg), indicating extensive extravascular distribution. |
| Bioavailability | Oral bioavailability is approximately 62% (range 50–80%).Intravenous bioavailability is 100%.Intramuscular bioavailability is approximately 78% (if administered as IM injection, though not a standard route for ALOXI). |
| Onset of Action | IV: Onset of antiemetic effect within 1–3 minutes after infusion. Oral: Onset within 1–2 hours. |
| Duration of Action | Duration of antiemetic effect persists up to 24 hours after a single dose, with clinical efficacy lasting throughout the chemotherapy cycle (up to 5 days) due to long half-life. |
0.25 mg intravenously over 30 seconds, administered 30 minutes before chemotherapy on day 1 of each cycle; not to be repeated within 7 days.
| Dosage form | CAPSULE |
| Renal impairment | No dose adjustment required for GFR ≥30 mL/min. For GFR <30 mL/min, use with caution; no formal recommendation due to lack of data. |
| Liver impairment | No dose adjustment required for Child-Pugh Class A or B. For Child-Pugh Class C, use with caution; no formal recommendation. |
| Pediatric use | For children aged 1 month to 17 years: 0.02 mg/kg (maximum 0.25 mg) intravenously over 30 seconds, administered 30 minutes before chemotherapy, once per cycle. |
| Geriatric use | No specific dose adjustment for elderly patients; use same dosing as adults, with consideration for renal function and comorbidities. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ALOXI (ALOXI).
| Breastfeeding | Unknown if excreted in human breast milk. Caution advised; consider developmental benefits of breastfeeding versus drug exposure. M/P ratio not available. |
| Teratogenic Risk | Pregnancy Category B. No evidence of teratogenicity in animal studies at doses up to 4 mg/kg/day. Insufficient human data; risk cannot be excluded. Use only if clearly needed. First trimester: limited data, theoretical risk. Second/third trimesters: no known fetal harm, but data are limited. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to palonosetron or any component of the formulation"]
| Precautions | ["Serotonin syndrome: risk when used with other serotonergic drugs (e.g., SSRIs, SNRIs, MAOIs)","Hypersensitivity reactions including anaphylaxis","QT prolongation and torsades de pointes; avoid in patients with electrolyte abnormalities, congenital long QT syndrome, or concurrent use of other QT-prolonging drugs","Constipation: monitor bowel function, especially in patients with gastrointestinal obstruction or ileus"] |
| Food/Dietary | No significant food interactions. May be taken without regard to food. |
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| Monitor for injection site reactions, headache, constipation, and QT prolongation (rare). No specific fetal monitoring required beyond routine prenatal care. |
| Fertility Effects | No studies on human fertility. Animal studies show no impairment of fertility at doses up to 4 mg/kg/day. |
| Clinical Pearls |
| Palonosetron (Aloxi) is a 5-HT3 receptor antagonist with a long half-life (~40 hours) and higher receptor binding affinity than other agents in its class. It is superior for prevention of delayed chemotherapy-induced nausea and vomiting (CINV) with moderately emetogenic chemotherapy (MEC) when combined with dexamethasone. No dose adjustment needed for renal or hepatic impairment. Administer over 30 seconds IV push, 30 minutes before chemotherapy. Not effective for established nausea/vomiting. May cause QT prolongation; avoid in patients with congenital long QT syndrome or with other QT-prolonging drugs. |
| Patient Advice | This medication is given before chemotherapy to prevent nausea and vomiting. · Common side effects include headache, constipation, diarrhea, or dizziness. · Avoid driving or operating heavy machinery if you feel dizzy or tired. · Tell your healthcare provider about all medications you take, especially heart rhythm drugs. · The effect lasts for several days; you may not need additional antiemetics for up to 5 days. · Report any signs of allergic reaction (rash, itching, swelling) or irregular heartbeat. |