Researchers from Finland have found that a common over-the-counter drug for heartburn and gastric ulcer can relieve some of the symptoms associated with schizophrenia.
Professor Jesper Ekelund, M.D., and his team showed that a very large dose of famotidine (200 mg daily) can penetrate the so-called blood-brain barrier and affect the histamine system in the brain.
Under the brand name Pepcid, famotidine has been used for the treatment of heartburn since the 1980s, but at regular dosing, famotidine almost does not enter the brain at all, since the brain is protected by the blood-brain barrier.
But the researchers reported that by increasing the dosage five-fold, the drug was able to enter the brain and affect the histamine system.
Researchers said that within one week the symptoms of persons suffering from schizophrenia started to ease, and after four weeks of treatment, symptoms had decreased significantly.
For the study, researchers randomly divided 30 persons suffering from schizophrenia into two groups, one which received famotidine and the other, placebo. All of the patients who took famotidine responded positively to the treatment while the symptoms of those who were on a placebo did not change.
Schizophrenia is the most common and severe psychotic disorder, and is the cause of at least half of all psychiatric hospital treatment days.
Researchers say this is the first randomized, controlled trials in humans to test the effect of histamine (H2) blockade in schizophrenia.
The rationale for the treatment traces to 1963, when the later Nobel prize winner Arvid Carlsson showed that dopamine has a central role in psychosis.
Thereafter, the so called dopamine hypothesis has been central in psychosis.
All presently available medications for psychosis are based around this principle. Since treatment response is all too often incomplete and side effects common, there is still a great, unmet medical need for medications with other mechanisms of action.
Many other signaling substances have been the focus of attention, but so far, the brain’s histamine system has mainly been implicated in the side effects of many psychosis medications.
Famotidine works by blocking the histamine H2 receptor. There are important neurons in the brain that use histamine as their primary signaling substance. These neurons have an important role as regulators of other signaling substances.
Despite the success in the study, researchers said famotidine shouldn’t be used directly as treatment for schizophrenia until long-term use of a dose of this size has been proved safe.
Ekelund said he believes the study shows that the histamine system in the brain offers a novel approach to treating psychosis. The study results, he hopes, will lead to increased efforts by the pharmaceutical industry to develop medications targeting the histamine system.
Source: University of Helsinki