100 MIgraine Drugs, A to Z: granisetron

Granisetron (Kytril, Sancuso) is one of the anti-nausea medications in the family of setrons. Ondansetron (Zofran) and palonosetron (Aloxi) are the other two drugs in this family available in the US. These drugs are approved for the prevention and treatment of chemotherapy-induced and post-surgical nausea and vomiting, but are also used to treat nausea of migraine attacks.

Granisetron was found to relieve nausea as well as pain in one anecdotal observation of 7 patients and two controlled trials.

The first study was conducted in Canada and it involved 28 patients who presented to the emergency department with an acute migraine. This was a randomized, double-blind, placebo-controlled study of intravenous granisetron (40 micrograms/kg or 80 micrograms/kg). Significant improvement in headache pain was observed in the 80-micrograms/kg group. Except for more nausea at 30 min in the placebo group, no significant differences were noted between treatments. The authors concluded that “granisetron may be effective for acute migraine headache; however, further studies with increased patient numbers are required.”

The second Iranian study was also conducted in an emergency room and included 148 patients. The doctors compared intravenous granisetron, 2 mg with intravenous metoclopramide, 10 mg. They found that the drugs were equally effective in the treatment of nausea, but granisetron was somewhat better at relieving pain.

The general consensus is that setrons are not very effective for the treatment of migraine pain, while metoclopramide (Reglan) and phenothiazine drugs, such as prochlorperazine (Compazine), promethazine (Phenergan) and chlorpromazine (Thorazine) relieve both nausea and pain. However, setrons have the advantage of not having the potential to cause serious neurological side effects. These include severe restlessness and involuntary movements (tardive dyskinesia), which in rare cases can become permanent.

We do treat patients with an acute migraine in the office and after an infusion of magnesium usually start with ondansetron and a pain medicine such as ketorolac (Toradol), but in some people, metoclopramide is consistently more effective. If metoclopramide causes restlessness, intravenous diphenhydramine (Benadryl) almost always stops it.