Health

Melatonin - Medicinal Uses, Interactions, Side Effects, Dosage

Melatonin

Melatonin, N-acetyl-5-methoxytryptamine, is an endogenous indolamine hormone that is released by the pineal gland in significant quantities in a circadian pattern.

Uses and Benefits:

Melatonin is most often used for insomnia and jet lag. It is also used by night-shift workers and for blind entrainment (to regulate sleep patterns in those who are blind). It has been researched as an oral contraceptive, antioxidant, and anticancer agent.

Pharmacology:

Regulation of melatonin secretion corresponds to the habitual sleep-wake hours in humans. Thus, melatonin secretion increases during nightfall, 9 PM-4 AM, and levels gradually decline until daylight. Exogenous melatonin has been used to supplement endogenous melatonin production for a number of indications.

Clinical Trials:

. Insomnia-Several randomized, double-blind clinical trials have been conducted evaluating the role of oral melatonin in patients with insomnia. These studies all suggest melatonin im­proves the quality of sleep, sleep onset, and sleep duration. These trials were small (usually involving 6-20 patients) and used subjective assessments of sleep. Dosing, patient age, timing of drug administration, method of randomization, study duration, and type of monitoring varied greatly. More recently, a randomized, double-blind, placebo-controlled clinical trial, using objective

Adverse Effects:

Melatonin is well tolerated, and its use can ;avoid the daytime somnolence commonly experienced with over-the-counter hypnotics. In clinical trials, melatonin has been associated with daytime drowsiness, tachycardia, dysthymia, and headache-but rarely. Reversible cases of acute psychosis, acute amnesia, and erythematous plaques have been reported.

Side Effects and Interactions:

No drug interactions have been reported with melatonin. Many drugs, however, have been shown to increase and decrease endogenous melatonin levels ; the clinical significance of this effect is unknown.

Cautions:

Patients with mania or bipolar disease may be at risk since melatonin may worsen mania. High-dose melatonin (up to 300 mg) has suppressed luteinizing hormone (LH) surge and partially inhibited ovulation when combined with a progestin. Therefore, melatonin should be avoided in women who are attempting to conceive. Long-term use of melatonin is not recommended due to a lack of data. A negative feedback effect on endogenous melatonin has not been observed in clinical trials of short duration. However chronic melatonin administration may decrease prolactin levels, and use should be discouraged while nursing. Due to a lack of safety data, melatonin should be avoided during pregnancy.

Preparations & Doses:

Dosing for melatonin varied widely in clinical studies, and products are available in a wide range of doses. Sustained-release products have not shown a significant benefit and generally cost more than immediate-release melatonin.

For insomnia, the lowest effective dose in clinical trials was 0.3 mg. If a low dose is ineffective, additional dosing up to a maximum of 10-20 mg may be required. Melatonin should be taken 30 minutes prior to the desired sleep time and lights should be turned off.

For jet lag, doses between 0.5 and 8 mg of the immediate-release formulation taken on the evening of departure have been used in the clinical trials. The most effective dose, timing of administration, and duration of use have not been determined. Typical jet lag symptoms usually resolve within 6 days after destination arrival.

To prevent potential viral transmission and contamination, products derived from animal pineal glands should be avoided; products that use a synthetic form of melatonin are preferable.

Summary Evaluation

Melatonin appears to be of value in alleviating sleep-onset insomnia. Currently, the literature does not support its use in sleep­maintenance insomnia. Melatonin may help reduce jet lag by facilitating sleep at the desired time upon arrival; however, study results are conflicting. Melatonin is well tolerated and is associ­ated with less daytime drowsiness than other over-the-counter hypnotics. Thus, it is an acceptable alternative for sleep induction and for managing similar sleep disturbances.

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Steve Mathew is a writer, who writes many great articles on herbal medicines for common ailments and diseases. For more information on herbal remedies and home remedies visit our site on health care.

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