What is Palonosetron (Aloxi)?

Palonosetron (Aloxi) belongs to the class of drugs called serotonin (5-HT3) receptor antagonists. Serotonin is a natural chemical present in the body that is responsible for the induction of nausea and vomiting.

The most common side effect cancer patients face during and after cancer drug treatment (chemotherapy) or surgery is nausea and vomiting. Palonosetron is an intravenous medication used to prevent or treat nausea and vomiting that may occur within 24 hours of receiving chemotherapy or undergoing surgery.

What Drug Class Is Palonosetron?

Palonosetron is a serotonin (5-HT3) receptor antagonist. 

Blocking 5-HT3 results in the blockage of serotonin both peripherally, in the gastrointestinal tract, and centrally in the chemoreceptor trigger zone of the brain, which results in a strong antiemetic effect. 

Brand Name

Palonosetron is sold under the brand name, Aloxi.

What Is an Antiemetic Drug?

In medical terms, emesis is described as the process of vomiting. An antiemetic agent is a drug that is used to prevent nausea and vomiting.

What Is Palonosetron Used For?

Palonosetron is used to prevent and manage acute or delayed nausea and vomiting related to initial and subsequent courses of chemotherapy. It can also be given to prevent nausea and vomiting up to 24 hours after an operation.

5-HT3 receptor antagonists are FDA-approved drugs, mainly used to prevent nausea and vomiting in adults and children undergoing cancer treatments. For example, it may be used after receiving cancer-treating drugs (chemotherapy), undergoing radiation therapy, or experiencing nausea and vomiting associated with postoperative anesthesia.

Route of Administration and Strength 

Palonosetron is only available as an intravenous injection in the United States. 

The drug comes in a sterile, clear, and colorless vial that contains 0.25 mg of drug per 5 ml. 

Dosage

In adults (17 years and older), palonosetron injection is given 30 minutes before the start of chemotherapy. The infusion is given over 30 seconds as a single 0.25 mg dose.  

In children from one month to less than 17 years of age, the injection is infused 30 minutes before the start of chemotherapy, and it is dosed at 20 micrograms per kilogram. Infusion is given over 15 minutes as a single dose.  

The dose of palonosetron injection given to prevent postoperative nausea and vomiting in adults is 0.075 mg IV administered 10 seconds immediately before administering anesthesia as a single dose.

Instructions Before Administration:

Before administering palonosetron injection:

• Visually examine the vial for any particulate matter or discoloration. If present, do not administer and discard immediately.
• Do not mix with any other medication.
• Before and after the administration, flush the infusion line with normal saline.  

What Are the Side Effects of Palonosetron?

Side effects vary from patient to patient. The two common side effects of palonosetron include:

• Headache
• Constipation

Serious side effects include:

• Chest pain
• Trouble breathing
• Nausea or vomiting
• Diarrhea
• Fast or irregular heartbeat
• QT prolongation
• Loss of coordination
• Stiff muscles or muscle twitching
• Swollen face
• Hives
• Sweating or shivering
• Agitation and hallucinations 

If any of the above side effects occur, patients should seek immediate medical attention. Patients taking other medications that can increase serotonin levels in the body, such as anti-depression medications, should be monitored more closely throughout therapy.  

Is Palonosetron Chemotherapy?

No, it is an antiemetic drug given before chemotherapy to prevent nausea and vomiting.

Does Palonosetron Cause Constipation?

Constipation and headache are the most common side effects associated with palonosetron injection. If the condition gets severe, the patient should inform their doctor or pharmacist.

What Are the Best Anti-nausea Medications for Chemotherapy?

The best anti-nausea medications for chemotherapy include:

• Ondansetron (Zofran)
• Palonosetron (Aloxi)
• Dolasetron (Anzemet)
• Granisetron (Kytril)

Palonosetron vs. Ondansetron

According to research and clinical trials carried out on patients who were treated with palonosetron and ondansetron, palonosetron was shown to be clinically more effective in treating chemotherapy-induced nausea and vomiting than ondansetron.

Moreover, the safety and efficacy of palonosetron for the prevention of chemotherapy-induced nausea and vomiting were proved in various clinical trials.

Contraindications

Palonosetron should not be given to patients with known hypersensitivity or allergy to palonosetron or any of its components.

Precautions

Serotonin Syndrome

Serotonin syndrome is when your body has too much serotonin. It usually occurs when patients use a combination of serotonergic drugs together, for example, SSRIs (selective serotonin reuptake inhibitors), SNRIs (serotonin and norepinephrine reuptake inhibitors), monoamine oxidase inhibitors, lithium, 5-HT3 receptor antagonists, fentanyl, or other antidepressants. 

Symptoms of serotonin syndrome should be monitored in patients while receiving palonosetron injection, as the condition can also occur without concomitant serotonin medication intake. Symptoms include:

• Mental instability issues like agitation, hallucination, or coma.
• Autonomic instability like tachycardia, irregular blood pressure, dizziness, and flushing.
• Neuromuscular problems like tremors, seizures, rigidity, or incoordination.
• Nausea, vomiting, and diarrhea.

Drug Interactions

Drugs that may interact with palonosetron include:

• Other serotonin drugs
• Herbal medicines
• Vitamins

Please inform your doctor and pharmacist of any other prescription or over-the-counter medications that you are taking before receiving a palonosetron injection. 

Half-life

The termination half-life of palonosetron injection is approximately 40 hours. 

Conclusion

Nausea and vomiting are very common occurrences after chemotherapy. Palonosetron hydrochloride is injected as a prophylactic treatment 30 minutes before initiating chemotherapy to prevent nausea and vomiting for up to 24 hours. It is administered only once as a single-dose IV infusion. Headache and constipation are the most common side effects of palonosetron. The drug should be used with caution during pregnancy, breastfeeding, and when there is a known allergy to palonosetron or any of its compounds. Additionally, drug use should be avoided or used with monitoring in patients receiving serotonergic drugs, especially antidepressants, and any other drugs known to interact with palonosetron.