Palonosetron
JFDA label: Aloxi 0.25mg/5ml
Mechanism of Action
Palonosetron is a selective 5-HT3 receptor antagonist, blocking serotonin, both on vagal nerve terminals in the periphery and centrally in the chemoreceptor trigger zone
Indications
Approved
- Capsules [Canadian product]
- Chemotherapy-induced nausea and vomiting
- Postoperative nausea and vomiting
Off-label
- Chemotherapy-induced nausea and vomiting, moderately emetogenic chemotherapy (pediatrics)
Contraindications
Source: Lexicomp
- Known hypersensitivity to palonosetron or any component of the formulation Absolute
Adverse Reactions
Cardiac disorders (1)
Common Prolonged Q-T interval on ECG
Hepatobiliary disorders (2)
Common Increased serum ALT · increased serum AST
Renal and urinary disorders (1)
Common Urinary retention
Metabolism and nutrition disorders (1)
Common Hyperkalemia
Gastrointestinal disorders (3)
Common Constipation · diarrhea · flatulence
Musculoskeletal and connective tissue disorders (1)
Common Weakness
Dosing
Source: Lexicomp
Warnings & Precautions
Source: Lexicomp
ECG effects
Selective 5-HT3 receptor antagonists have been associated with dose-dependent increases in ECG intervals (eg, PR, QRS duration, QT/QTc, JT). A thorough QT/QTc study evaluating the effect of palonosetron on QT/QTc demonstrated a magnitude of effect less than the threshold for regulatory concern (Morganroth 2016). Reduction in heart rate may occur with the 5-HT3 antagonists, including palonosetron (Gonullu 2012).
Hypersensitivity reactions
Hypersensitivity (including anaphylaxis) has been reported in patients with or without known hypersensitivity to other 5-HT3 receptor antagonists.
Serotonin syndrome
Serotonin syndrome has been reported with 5-HT3 receptor antagonists, predominantly when used in combination with other serotonergic agents (eg, SSRIs, SNRIs, MAOIs, mirtazapine, fentanyl, lithium, tramadol, and/or methylene blue). Some of the cases have been fatal. The majority of serotonin syndrome reports due to 5-HT3 receptor antagonists have occurred in a post-anesthesia setting or in an infusion center. Serotonin syndrome has also been reported following overdose of another 5-HT3 receptor antagonist. Monitor patients for signs of serotonin syndrome, including mental status changes (eg, agitation, hallucinations, delirium, coma); autonomic instability (eg, tachycardia, labile blood pressure, diaphoresis, dizziness, flushing, hyperthermia); neuromuscular changes (eg, tremor, rigidity, myoclonus, hyperreflexia, incoordination); gastrointestinal symptoms (eg, nausea, vomiting, diarrhea); and/or seizures. If serotonin syndrome occurs, discontinue 5-HT3 receptor antagonist treatment and begin supportive management. Concurrent drug therapy issues:
Drug-drug interactions
Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information. Other warnings/precautions:
Chemotherapy-associated emesis
Antiemetics are most effective when used prophylactically (Roila 2016). If emesis occurs despite optimal antiemetic prophylaxis, re-evaluate emetic risk, disease, concurrent morbidities and medications to assure antiemetic regimen is optimized (Hesketh 2017).
Postoperative nausea and vomiting
Use is not recommended if there is little expectation of postoperative nausea and vomiting (PONV); may use for low expectation of PONV if it is essential to avoid nausea and vomiting in the postoperative period.
Pregnancy & Lactation
Pregnancy
Adverse events have not been observed in animal reproduction studies. Use during pregnancy only if clearly needed.
Lactation
It is not known if palonosetron is present in breast milk. Due to the potential for adverse reactions in the breastfed infant, the manufacturer recommends a decision be made whether to discontinue breastfeeding or to discontinue palonosetron, taking into account the importance of treatment to the mother.
Chemistry & Properties
| Formula | C19H24N2O |
|---|---|
| Molecular weight | 296.41 g/mol |
| IUPAC name | (3aS)-2-[(3S)-1-azabicyclo[2.2.2]octan-3-yl]-3a,4,5,6-tetrahydro-3H-benzo[de]isoquinolin-1-one |
| CAS | 135729-61-2 |
| PubChem CID | 6337614 |
| InChIKey | CPZBLNMUGSZIPR-NVXWUHKLSA-N |
| logP | 2.66 (XLogP 2.8) |
| Polar surface area | 23.55 Ų |
| H-bond acceptors / donors | 2 / 0 |
| Drug-likeness (QED) | 0.80 |
| Lipinski violations | 0 |
SMILES
O=C1c2cccc3c2[C@H](CCC3)CN1[C@@H]1CN2CCC1CC2Biology & Pharmacokinetics
Pharmacokinetics predicted
| Bioavailability | 10.0% |
|---|---|
| Half-life | 1.552 h |
| Volume of distribution | 5.953 L/kg |
| Protein binding | 66.4% |
| BBB penetrant | Yes |
Enzyme interactions
| Enzyme | Role | Detail |
|---|---|---|
| CYP1A2 | Substrate | — |
| CYP2B6 | Inhibitor | — |
| CYP2C19 | Substrate | — |
| CYP2D6 | Substrate | — |
| CYP3A4 | Substrate | — |
Receptor binding (top 1)
| Target | Action | Affinity |
|---|---|---|
| 5-HT3A (HTR3A) | Antagonist | pKi 10.5 |
Transporters
BCRP (Inhibitor)BSEP (Inhibitor)MRP1 (Inhibitor)OATP1B1 (Inhibitor)OATP1B3 (Inhibitor)P-gp (Inhibitor)P-gp (Substrate)
Drug–drug interactions (100+, DDInter)
| Interacting drug | Severity | Management |
|---|---|---|
| Alfentanil | major | |
| Almotriptan | major | |
| Amiodarone | major | |
| Amisulpride | major | |
| Amitriptyline | major | |
| Amoxapine | major | |
| Anagrelide | major | |
| Apomorphine | major | |
| Arsenic trioxide | major | |
| Bedaquiline | major | |
| Bepridil | major | |
| Bupropion | major | |
| Buspirone | major | |
| Cabozantinib | major | |
| Ceritinib | major | |
| Chloroquine | major | |
| Cisapride | major | |
| Citalopram | major | |
| Clomipramine | major | |
| Clozapine | major | |
| Crizotinib | major | |
| Desipramine | major | |
| Desvenlafaxine | major | |
| Dexfenfluramine | major | |
| Dextromethorphan | major | |
| Disopyramide | major | |
| Dofetilide | major | |
| Dolasetron | major | |
| Doxepin | major | |
| Doxepin (topical) | major | |
| Dronedarone | major | |
| Droperidol | major | |
| Duloxetine | major | |
| Efavirenz | major | |
| Eletriptan | major | |
| Escitalopram | major | |
| Fenfluramine | major | |
| Fentanyl | major | |
| Fingolimod | major | |
| Fluoxetine | major |
Showing 40 of 100+.
Registered Products (3)
| Brand | Form / strength | Pack | Agent | Citizen (JOD) |
|---|---|---|---|---|
| Akynzeo | Capsule 0.5 mg, 300 mg | 1 cap | Sukhtian Group | 62.160 |
| Aloxi | Vial 0.25 mg/5 ml | 1 vial | Sukhtian Group | — |
| Megatron | Vial 0.05 mg/ml | 1 vial | MS PHARMA/JORDAN | — |