The researchers have also found that candesartan may work for patients who get no relief from propranolol.
“This gives doctors more possibilities and we can help more people,” says Professor Lars Jacob Stovner, leader of Norwegian National Headache Centre, who also led the study.
If one drug doesn’t work for the migraine patient, the other one may. Side effects may also vary from patient to patient.
The new study is a follow-up on a ten-year-old study from NTNU.
Candesartan is already in use by several doctors as a migraine prophylactic, but the NTNU follow-up study, which confirms the study from a decade ago, provides the proof that the drug actually works.
More than 20 percent of migraine patients report that they feel better even when they are given a placebo. But blind tests show that candesartan works preventively for another 20 to 30 percent of patients. The hope is now that candesartan will be even more commonly prescribed.
Migraines are thought to affect a staggering one billion people worldwide. Twelve percent of the Norwegian population suffers from migraines, or more than 500,000 individuals. This poses problems for the individual, but is also costly for society in the form of sick leave and reduced ability to work. Preventing migraines thus offers many benefits.
Triple blind test
The NTNU study was a triple blind test, which means that neither patients nor doctors nor those who analyzed the results knew whether the patients had been given placebo or real medicine, Stovner said.
Researchers tested both candesartan and propranolol. In all, 72 patients took part of the study this time, the same number as ten years ago. These patients were normally affected by migraine attacks at least twice every month. The patients used each treatment (candesartan, propranolol or placebo) for 12 weeks, and also underwent four weeks before start and between the treatment periods without any medication at all. Thus every patient was part of the study for almost a year.
Candesartan was originally a medication used to treat high blood pressure, but Harald Schrader, a retired professor from St. Olavs Hospital in Trondheim, who himself had both high blood pressure and migraine, discovered by chance in the 1990s that candesartan also worked well for his own headaches.
This finding led to the subsequent studies of the drug. The studies received partial support from AstraZeneca, but the research was conducted independent of the drug manufacturer. Lars Jacob Stovner and Erling Tronvik, a postdoc, have been among the most active in the research.
Candesartan is today marketed under the name Atacand, while propranolol is marketed under the name Inderal. But there are also several copies on the market.
“The patent is running out,” Stovner says.
This also means that more patients will have access to cheaper, generic forms of the medicine. Candesartan will now very likely be part of the guidelines for the prophylactic treatment of migraine the world over.