Novel Therapy Allows Those With Sleep Apnea To Breathe Easy

Anesthesia can stay in the body for up to twenty-four hours after it is administered. A patient will not return to their normal self until the anesthetic is completely eliminated from the body.

The American Association of Nurse Anesthetists advises patients to avoid the following activities until anesthesia completely wears off: driving a car, operating complex equipment, signing any legal documents, taking medications other than those prescribed by your physician, and drinking alcohol.
               
Research shows anesthesia poses an increased danger for those suffering from sleep apnea. This is because general anesthesia suppresses the activity of muscles in the upper airway, increasing the number of episodes of airway obstruction characteristic of sleep apnea.

Anesthesia also decreases the ability of a person to wake up when an apnea episode takes place. Because of these risks, sleep apnea patients generally need to remain under the watchful eye of medical personnel for a longer period of time after surgery than patients without the condition.

Sleep apnea is a surprisingly common condition: according to the National Institutes of Health, the disorder affects more than twelve million Americans, making it as common as adult diabetes. Certain factors increase the risk of sleep apnea, such as being male, overweight, and over the age of forty; but sleep apnea can strike anyone at any age, including children. The vast majority of sufferers go undiagnosed and untreated. Untreated, sleep apnea can lead to high blood pressure and other cardiovascular diseases, memory problems, weight gain and diabetes, impotence, and headaches.

In addition to anesthetic agents used during surgery, sufferers of sleep apnea need to be mindful of how they use certain narcotic analgesics (pain relievers) after surgery. Like anesthesia, many drugs and agents used post-surgery to relieve pain and to depress consciousness remain in the body at low amounts for hours or even days afterwards.

Researchers at the University of Alberta and Cortex Pharmaceuticals, a neuroscience company based in Irvine, California, believe that a novel class of molecules known as AMPAKINE compounds may provide protection from drug-induced respiratory depression, while simultaneously allowing the sedative or analgesic to continue working as it was intended.

AMPAKINE compounds act on the most common excitatory receptor in the brain, the AMPA-type glutamate receptor. Dr. John J. Greer of the University of Alberta demonstrated that certain AMPAKINE compounds stimulate primitive areas of the brain called the pre-Botzinger Complex that controls breathing, without causing side effects.

In animal models, AMPAKINE compounds were shown to enhance the respiratory drive and breathing rhythm in laboratory rats whose respiration rates were purposely suppressed by administration of central nervous system depressants. 

The company recently announced that the UK’s Medicines and Healthcare product Regulatory Agency (MHRA) gave it permission to proceed with the clinical development of CX1739 in subjects with moderate to severe sleep apnea. The study will be conducted in a UK sleep unit using a double-blind, placebo-controlled design in twenty subjects.

“CX1739 has been very well tolerated in Phase I healthy volunteer studies, and we are excited to be able to proceed with an efficacy study in sleep apnea,” said Dr. Mark Varney, President and Chief Executive Officer of Cortex.

Data obtained from animal studies have demonstrated that AMPAKINE compounds can specifically stimulate breathing by activating regions in the brain stem.  Last year, Cortex announced positive results of two clinical studies that demonstrated the AMPAKINE compound, CX717 could prevent the depression of breathing induced by an opioid analgesic. Further analyses of these clinical studies also showed that CX717 reduced both the number and duration of apnea events caused by the opioid. Studies in animals suggest that CX1739 is approximately three times better than CX717 at reversing breathing depressed by opioids. CX1739 also stimulates another brain region that regulates muscle tone in the upper airways. “Our hypothesis is that by stimulating breathing and increasing muscle tone in the upper airways, CX1739 will be effective in maintaining breathing throughout the night in sleep apnea patients,” commented Dr. Varney.

AMPAKINES could one day allow for improved safety and a more effective use of opiate analgesics and barbiturate sedatives, two important classes of central nervous system drugs. There is currently no drug treatment option available for sleep apnea and the market is considered a multi-billion dollar opportunity in North America alone.