Palonosetron injection is used to prevent nausea and vomiting that may occur within 24 hours after receiving cancer chemotherapy or surgery. It is also used to prevent delayed nausea and vomiting that may occur several days after receiving certain chemotherapy medications. Palonosetron injection is in a class of medications called 5-HT₃ receptor antagonists. It works by blocking the action of serotonin, a natural substance that may cause nausea and vomiting.

Palonosetron injection comes as a solution (liquid) to be injected intravenously (into a vein) by a healthcare provider in a hospital or clinic. When palonosetron is used to prevent nausea and vomiting caused by chemotherapy, it is usually given as a single dose about 30 minutes before the start of chemotherapy. If you are receiving more than one course of chemotherapy, you may receive a dose of palonosetron before each treatment cycle. When palonosetron is used to prevent nausea and vomiting caused by surgery, it is usually given as a single dose just before the surgery.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

Before receiving palonosetron injection,

• tell your doctor and pharmacist if you are allergic to palonosetron, alosetron (Lotronex), dolasetron (Anzemet), granisetron (Kytril, Sancuso), ondansetron (Zofran), or any other medications, or any of the ingredients in palonosetron injection. Ask your pharmacist or check the manufacturer's patient information for a list of the ingredients.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: fentanyl (Abstral, Actiq, Duragesic, Fentora, Lazanda, Onsolis, Subsys), lithium (Lithobid); medications to treat migraines such as almotriptan (Axert), eletriptan (Relpax), frovatriptan (Frova), naratriptan (Amerge), rizatriptan (Maxalt), sumatriptan (Imitrex), and zolmitriptan (Zomig); methylene blue; mirtazapine (Remeron); monoamine oxidase (MAO) inhibitors including isocarboxazid (Marplan), linezolid (Zyvox), phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate); selective serotonin reuptake inhibitors (SSRIs) such as citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem, in Symbyax), fluvoxamine (Luvox), paroxetine (Brisdelle, Paxil, Pexeva), and sertraline (Zoloft); and tramadol (Conzip, Ultram, in Ultracet). Your doctor may need to change the doses of your medications or monitor you more carefully for side effects.
• tell your doctor if you have or have ever had any medical condition.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while receiving palonosetron injection, call your doctor.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

• seizures
• fainting
• difficulty breathing
• pale or blue-colored skin

Unless your doctor tells you otherwise, continue your normal diet.

Palonosetron injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• headache
• constipation
• pain, redness, or swelling at the injection site

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• hives
• rash
• itching
• difficulty breathing or swallowing
• chest pain
• swelling of the face
• changes in heart beat or heart rhythm
• dizziness or lightheadedness
• fainting
• fast, slow or irregular heartbeat
• agitation
• confusion
• nausea, vomiting, and diarrhea
• loss of coordination
• stiff or twitching muscles
• seizures
• coma (loss of consciousness)

Palonosetron injection may cause other side effects. Call your doctor if you have any unusual problems while receiving this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Keep all appointments with your doctor.

Ask your doctor any questions you have about your medication.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

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