Last Updated: 2001-07-06 13:29:03 EDT (Reuters Health)

By Roxanne Nelson

VANCOUVER, British Columbia (Reuters Health) – As a person ages, the incidence of sleep disorders increases and the quality of sleep decreases. But melatonin usage may help older persons with insomnia, according to two related studies presented here on Wednesday at the 17th Congress of the International Association of Gerontology.

Israeli researchers reported that controlled-release melatonin (CRM) improved sleep quality in type 2 diabetics with insomnia and also facilitated discontinuation of benzodiazepines in an elderly population.

"Melatonin is secreted in response to darkness," said Dr. Doron Garfinkel, who is from the department of Aging Research and Internal Medicine at E. Wolfson Medical Center, in Holon. "It induces sleep through its synchronizing effect on the internal biologic clock."

In a randomized double-blind crossover trial, 38 type 2 diabetics used CRM or a placebo for 3 weeks. The objective of the study was to assess the efficacy of CRM in improving sleep quality in diabetic patients, and also to evaluate its influence on antioxidants, biochemicals and metabolic parameters.

At follow-up, there was a 3.6% increase in sleep efficiency, and a 38.6% decrease in nocturnal awakenings.

"The patients had been spending more than an hour awake, Dr. Garfinkel told conference attendees. "The time awake went down from an average of 63 minutes to 31 minutes, so it's quite an impressive improvement."

CRM had no significant effect on serum glucose, fructosamine, insulin, C-peptide or antioxidant levels. It did appear, however, to influence hemoglobin A1C (HbA1C) concentration, and after 6 months of using CRM at a dosage of 2 mg, HbA1C concentrations decreased. This effect was most pronounced in diabetics who high HbA1C levels.

Dr. Garfinkel concluded that overall, CRM replacement therapy improved sleep quality in type 2 diabetics suffering from insomnia, and also had a beneficial effect on HbA1C levels.

The second study, the investigators found that CRM effectively facilitated withdrawal from benzodiazepines, which were prescribed for sleep disorders.

"Benzodiazepines are widely used in the elderly population for the initiation of sleep," Dr. Garfinkel said. "And we also know that very frequently complaints about poor sleep maintenance persist, despite benzodiazepine treatment."

According to literature, benzodiazepines are only supposed to be used for 6 weeks, but they are often used for months or even years, he added. Benzodiazepines can also inhibit and suppress nighttime production of melatonin.

In a double-blind controlled trial, 34 benzodiazepine users were given 2 mg of CRM or placebo nightly

The subjects were encouraged to decrease their benzodiazepine usage by 50% during week 2, by 75% between weeks 3 and 4, and to stop completely between weeks 5 and 6. CRM was later administered to all of the study subjects for another 6 weeks.

At week 6, almost 80% of the subjects were able to discontinue their benzodiazepines. After 2 years, 60% of the subjects had not gone back to using them. Of this group, 52% continued to take CRM.

Eighteen percent of the group was able to reduce usage of benzodiazepines by about 30%. All of the study participants reported good quality of sleep, despite the fact that they had either discontinued or stopped their benzodiazepines.

Dr. Garfinkel concluded that "controlled release melatonin can facilitate benzodiazepine discontinuation, or significantly reduce its dosage, while maintaining the same or better sleep."

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