Unusual Remedy Helps Sleep Apnea

Nov. 19, 2003 -- Sleep apnea sufferers may benefit from the main ingredient in a poisonous African bean.

The drug is called physostigmine. It's the main ingredient of the deadly Calabar bean, once used in Africa in trial-by-ordeal rituals. Physostigmine is used as an antidote for organophosphate poisoning and also to treat certain types of glaucoma. Now it may help treat people with obstructive sleep apnea.

Obstructive sleep apnea is a type of sleep-disordered breathing. Many times during the night, people with the condition briefly stop breathing for more than 10 seconds. The reasons for this aren't well understood but muscles within the airway collapse causing dangerous drops in oxygen levels.

Jan Hedner, MD, and colleagues at Sahlgrenska University, Göteborg, Sweden, learned that certain forms of sleep-disordered breathing might result from a chemical imbalance in the brain. Knowing that physostigmine counteracts this kind of chemical imbalance and that it can also help muscles contract, they reasoned that it might help people with sleep apnea.

They tested the idea on 10 patients with moderate to severe obstructive sleep apnea. Physostigmine is quickly eliminated from the body, so the patients received continuous infusions of the drug.

During the last third of the night -- as drug concentrations reached a steady plateau -- apnea events became significantly less frequent. The biggest drop came during the REM stage of sleep.

On average, the drug caused patients to lose 74 minutes of sleep. But those who got the greatest benefit lost the least sleep.

"This predominantly REM-related reduction of obstructive sleep apnea after physostigmine may provide a new treatment option if the effects are maintained in long-term studies," Hedner and colleagues conclude.

The findings appear in the November 2003 issue of the American Journal of Respiratory and Critical Care Medicine.

Hedner and some of his colleagues hold parts of patents on the use of physostigmine in sleep-disordered breathing.