Use of Melatonin

Melatonin is available without prescription and is classified worldwide as a natural substance rather than a medication as such. Although this makes melatonin widely available this also makes the formulation of melatonin much less reliable. Therefore the best option is to have the melatonin prepared on purpose by a compound pharmacist. Hopefully in the future a synthetic melatonin or melatonin-like medication may be available (one is currently available in North America). A 2 mg slow release formulation is also available in some countries (Circadin™). The usefulness of slow release formulation is doubtful.

Melatonin has also other properties. It is a potent anti-oxidant, has immune-modulatory activity and may reduce the risk of malignancy.

Side effects of melatonin

Melatonin is considered safe at the recommended doses, which varies between 0.5mg and up to 6mg. In most cases side effects are not different from placebo (a dummy capsule). However, symptoms such as fatigue, ‘dizziness’, headache and irritability and nausea are sometimes reported

Some attention has to be paid in the following situations.

  1. Warfarin. Melatonin may increase the activity of Warfarin and therefore if the patient is on anticoagulants, such as Warfarin, the activity of the medication has to be monitored
  2. Diabetes on insulin. Melatonin may increase the sensitivity to insulin in predisposing individuals and increase the risk of hypoglycemia.

  3. Blood pressure. Melatonin may cause a drop in blood pressure, which may be relevant particularly in the elderly and in patients who are already on blood pressure medication.

  4. Pregnancy and breastfeeding. Because of its action the use in pregnancy and in women planning to become pregnant is usually discouraged. Also the safety in women breastfeeding is not clear and should be avoided.

  5. Children. The use of melatonin in children before puberty should also be undertaken only if necessary and under medical supervision.

Timing of melatonin administration

Although it has been claimed that melatonin has a sleeping tablet-like effect, and therefore could be given just before going to bed, the best use of melatonin is to be taken about 3-4 hours before intended bedtime. The main activity of melatonin is of synchronizing the body function to favour sleep onset rather than inducing sleep. This is to say that if the person is under stress or is unable to switch off his thinking, melatonin is unlikely to put the person to sleep.

It should also be noted that taking melatonin at the wrong time of the day might actually have a reversal effect (disturbing sleep). For example melatonin taken in the morning, rather than the evening may delay sleep onset at night.