Granisetron

• Type of Drug: Antiemetic
• Prescribed for: Preventing nausea and vomiting after certain cancer chemotherapy treatments

Granisetron General Information

Granisetron, like Ondansetron, produces its effect in a unique way. It antagonizes the receptor for a special form of the neurohormone serotonin (5HT3). Receptors of this type are found in both the part of the brain that controls vomiting (chemoreceptor trigger zone) and the vagus nerve in the stomach and intestines.

Women absorb more Granisetron faster than men, and they clear the drug more slowly from their bodies. This means that women will have more drug in their blood than men after taking the same dose of Granisetron, but these differences have not been reflected in any difference in response to the drug.

Granisetron is extremely effective in preventing nausea and vomiting and works in situations where many older antiemetics are ineffective.

Cautions and Warnings

Don’t take Granisetron if you are allergic or sensitive to it. People with liver failure break the drug down about half as quickly as others, but dosage adjustment is generally not required.

Possible Side Effects

• Most common: headache, nausea, weakness, and constipation.
• Less common: abdominal pains, liver inflammation, vomiting, diarrhea, high blood pressure, dizziness, sleeplessness, anxiety, tiredness, fever, appetite reduction, anemia, low white-blood-cell and platelet counts, and hair loss.
• Rare: low blood pressure, angina pains, fainting, rapid heartbeat, and drug allergy (possibly including difficulty breathing, itching, rash, low blood pressure, and shock).

Granisetron Drug Interactions

• Granisetron is broken down in the liver by the same enzyme system responsible for breaking down many other drugs. It may be affected by other drugs that stimulate or inhibit these enzymes, but no interactions have been discovered to date.

Food Interactions

Food slightly decreases the amount of Granisetron absorbed but does not affect your Granisetron dose.

Usual Dose

Adult and Child (age 12 and older): 1 mg 2 times a day, given 1 hour before chemotherapy and then 12 hours later.

Child (age 11 and under): not recommended.

Overdosage

Little is known about Granisetron overdose. Call your local poison center or hospital emergency room for more information. If you go to the hospital for treatment, ALWAYS bring the medicine bottle with you.

Special Information

Call your doctor if you begin to have chest tightness, wheezing, trouble breathing, chest pains, or other unusual or severe side effects.

If you forget to take a dose of Granisetron, take it as soon as you remember. If it is almost time for your next dose, skip the dose you forgot and continue with the regular schedule. Forgetting more than 1 dose may increase your chances of vomiting.

Special Populations

Pregnancy/Breast-feeding
Animal studies with Granisetron have revealed no potential to cause birth defects. Nevertheless, pregnant women should not take this, or any other, drug unless the possible risks and benefits of taking it have been discussed with their doctors.
It is not known if Granisetron passes into breast milk. Nursing mothers who take this medicine should carefully observe their infants for possible drug side effects.

Seniors
Seniors may take this medicine without restriction.