New sleeping pill could be the answer to jet lag

Dec 3 2008

An experimental drug developed by Australian scientists could offer a new cure for jet lag and be a welcome alternative to addictive sedatives such as benzodiazepines.

The scientists from Monash University’s School of Psychology, Psychiatry and Psychological Medicine led by Dr. Shantha Rajaratnam, say the new drug Tasimelteon works by shifting the natural ebb and flow of the body's sleep hormone melatonin and could be available in the next few years.

Phase 2 trials and 3 trials have shown Tasimelteon is effective for transient insomnia caused by night shift work and jet-lag and could be a first-line therapy for such people - poor sleep is known to affect people's daytime performance.

The trials showed the drug can reset the body's natural circadian rhythms - such sleep disorders are common causes of insomnia that affect millions of individuals, including those who work at night or who cross multiple time zones during travel.

These primary sleep disorders are characterised by persistent and recurrent sleep disturbances, insomnia when trying to sleep, and excessive sleepiness while trying to remain awake and often occur when scheduled or desired sleep times are not compatible with the body's circadian rhythms, such as when a person has travelled across multiple time zones, or works night shifts.

Tasimelteon is a synthetic version of the sleep hormone melatonin that appears to treat both sleepiness and the underlying cause of the sleep problem. Natural melatonin is a hormone which peaks at night and is a popular treatment for patients with body clock-related sleep disorders but according to the researchers the potency, purity, and safety of melatonin pills currently on the market is unregulated.

The synthetic version is possibly more powerful than natural melatonin and experts say the drug would be a welcome alternative to addictive sedatives like benzodiazepines - melatonin based drugs are not addictive.

The experimental drug is under development by a U.S. pharmaceutical company and Dr. Rajaratnamis says they found it was able to shift the body clock to align the time the brain thinks it is, more closely with the time in reality.

The drug was trialled on a group of 450 Americans and it was found that it improved the ability to fall asleep and then stay asleep when bed time was shifted earlier by five hours.

Dr. Rajaratnam says this is the equivalent of travelling eastwards and putting your clock back five hours, such as returning from India to Melbourne, or Dubai to Perth.

Those given the drug had between 30 minutes and nearly two hours more sleep than volunteers who received a placebo.

The researchers say Tasimelteon works by targeting the brain’s melatonin receptors which help regulate sleep and wake cycles and this new class of hypnotics could be more effective for circadian-related insomnia than traditional hypnotics such as the controversial sleeping pill, Stilnox, which treat the immediate sleeplessness but fail to treat the underlying cause.

There were some mild side effects experienced, including nausea and headache and Dr. Rajaratnam says the drug will undergo rigorous testing before being approved.

The researchers say by simultaneously improving sleep latency and sleep maintenance with a shift in circadian rhythms, Tasimelteon has the potential for the treatment of patients with transient insomnia associated with circadian rhythm sleep disorders, including people affected by jet lag, or those who work at night, and early-riser workers.

The research is published in The Lancet.