Reviewed on 3/31/2022

What Is Granisetron and How Does It Work?

Granisetron is a prescription medication used for preventing nausea and vomiting caused by cancer chemotherapy or radiation therapy, and anesthesia used during surgery.

  • Granisetron is available under the following different brand names: Sustol, Sancuso, Granisol Oral Solution

What Are Dosages of Granisetron?

Adult and pediatric dosage

Injectable solution

Available as generics

  • 0.1mg/mL
  • 1mg/mL

Extended relase SC injection

  • 10mg/0.4mL single-dose prefilled syringe (Sustol)


  • 3.1mg/24hr (Sancuso)


Oral solution

  • 1mg/5mL (Granisol)

Chemotherapy-Induced Nausea & Vomiting

Adult  and geriatric dosage


  • 1 mg orally 1 hr before chemotherapy, then 1 mg 12 hr after 1st dose; OR 2 mg 1 hr before chemotherapy


  • 0.01 mg/kg/dose infused over 5 min or direct injected over 30 sec, 30 min before chemotherapy  

Patch (Sancuso)

  • 1 patch 24-48 hr before chemotherapy; keep at least 24 hr post-chemo treatment
  • May wear the same patch for up to 7 days

SC (Sustol)

  • 10 mg SC in combination with dexamethasone at least 30 minutes before the initiation of MEC or AC combination chemotherapy
  • Administer on Day 1 of chemotherapy and not more frequently than once q7days because of the extended-release properties of the formulation
  • Also, see Administration
    • Dexamethasone with Sustol
    • MEC regimen: Dexamethasone 8 mg IV on Day 1
    • AC combination chemotherapy regimens: Dexamethasone 20 mg IV on Day 1, followed by 8 mg orally twice daily on Days 2, 3, and 4
    • If administered with an NK1 receptor antagonist, see the prescribing information of the NK1 receptor antagonist for the recommended dexamethasone dosage

Pediatric dosage

  • Children below 2 years: Safety and efficacy not established
  • Children between 2-16 years: As adults; 0.01 mg/kg infused over 5 min or direct injection over 30 sec, 30 min before chemotherapy  
  • Oral administration: Currently FDA-approved for IV administration in children; safety and efficacy of oral administration is not established

Radiation-Induced Nausea & Vomiting

Adult and geriatric dosage

  • 2 mg orally, 1 hr before radiation treatment

Postoperative Nausea & Vomiting

Adult and geriatric dosage

  • Prevention: 1 mg (undiluted) IV push over 30 seconds; administer before anesthetic induction or immediately before reversal of anesthesia
  • Treatment: 1 mg (undiluted) IV push over 30 seconds

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Are Side Effects Associated with Using Granisetron?

Common side effects of Granisetron include:

  • diarrhea,
  • constipation,
  • stomach pain or upset,
  • loss of appetite,
  • weakness,
  • headache,
  • fever,
  • dizziness,
  • drowsiness,
  • trouble sleeping (insomnia), and
  • anxiety.

Serious side effects of Granisetron include:

  • unusual muscle movements or stiffness,
  • fast or pounding heartbeats,
  • fever,
  • body aches,
  • flu symptoms,
  • easy bruising or bleeding, or
  • unusual weakness.

Rare side effects of Granisetron include:

  • none 
This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Granisetron?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Granisetron has severe interactions with the following drug:
    • apomorphine
  • Granisetron has serious interactions with at least 54 other drugs.
  • Granisetron has moderate interactions with at least 24 other drugs.
  • Granisetron has minor interactions with no other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

What Are Warnings and Precautions for Granisetron?


  • Hypersensitivity
  • Coadministration with apomorphine; combination reported to cause profound hypotension and loss of consciousness

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Granisetron?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Granisetron?”


  • Liver disease
  • May mask paralytic ileus/gastric distension
  • Cross-sensitivity among selective 5-HT antagonists may occur
  • Serotonin syndrome was reported with 5-HT3 receptor antagonists alone but particularly with concomitant use of serotonergic drugs including SSRIs, SNRIs, MAO inhibitors, lithium, tramadol, methylene blue IV, and mirtazapine
  • Protect patch from sunlight
  • May prolong QT interval; coadministration with drugs known to prolong QT interval may result in serious arrhythmias
  • Mild application site reactions have occurred; remove the patch if severe reactions or generalized skin reactions occur
  • Avoid exposing granisetron patch and surrounding area to direct external heat sources, such as heating pads; plasma concentration continues to increase during the period of heat exposure

Pregnancy and Lactation

  • May be acceptable during pregnancy
  • Lactation
    • Excretion in milk unknown; use with caution
Medscape. Granisetron.

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