Melatonin: Does it help in the treatment of insomnia?

As seen in the Consultant Connection November 2013 Issue
Kimberly Baucher Ohio Northern University, PharmD Candidate

Melatonin is involved in many physiologic processes, including circadian rhythms, mood regulation, anxiety, sleep and appetite. Approximately 80% of patients older than 65 years old report sleep-related problems. Melatonin supplementation has become a popular over-the-counter treatment for insomnia. However, there is still a debate on whether this treatment is actually effective.
From recent clinical studies it appears that the only time melatonin supplementation would be effective is if the patient has a disturbance in melatonin levels. For example, one study looked at melatonin use in patients taking beta blockers as these have the potential to suppress nighttime melatonin secretion. This study did show significantly improved sleep quality (increased sleep time and decreased time to sleep onset) in patients receiving 2.5 mg of melatonin every night compared to placebo. This is just one example of when it may be beneficial to use melatonin. Other studies have shown benefits with melatonin use in patients who are deficient due to dialysis and other disease states. When considering use of melatonin in a patient, it is important, as with any medication, to consider risk versus benefit as well as ensuring there is an appropriate indication. The most common side effects to monitor for include daytime drowsiness, headache, depression, dizziness and nausea. If it is determined that melatonin should be tried, it should be monitored for efficacy and if the patient shows no improvement, it should be discontinued.
Most studies for melatonin use a dose of 3 mg every night. However; the recommended dose in insomnia is 3 to 5 mg every night, given three to four hours before bed. Melatonin may cause drowsiness within 30 minutes of ingestion which should be a consideration with administration time. Use of melatonin for more than four weeks has not been looked at in studies. 
References:
Dipiro JT. Sleep Disorders. Pharmacotherapy: a pathophysiologic approach. 2008. 1191-1201.
Comai S, Gobbi G. Unveiling the role of melatonin MT2 receptors in sleep, anxiety and other neuropsychiatric diseases: a novel target in psychopharmacology. J Psychiatry Neurosci. 2013 Aug 27; 38 (5): 130009.
Scheer FA, Morris CJ, Garcia JI, et al. Repeated melatonin supplementation improves sleep in hypertensive patients treated with beta-blockers: a randomized controlled trial. Sleep. 2012 Oct 1; 35 (10): 1395-1402.
LexiComp [database on the Internet]. Hudson (OH): LexiComp. 2013 [cited 2013 Sept 15]. Available from: http://online.lexi.com/crlsql/servlet/crlonline


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