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Melatonin/melatonin CR

Melatonin is a hormone that helps to regulates the body’s sleep/wake cycle.

What is this medication used for?

Melatonin may be used for relief of sleeping difficulties (insomnia), including difficulties falling asleep or staying sleep.

It may also be used for those with delayed sleep phase syndrome associated with conditions such as visual impairment, cerebral palsy, attention-deficit/ hyperactivity disorder (ADHD), autism spectrum disorder or developmental delay.

Melatonin is available “over the counter,” and does not require a prescription. Learn more about off-label medication use:

Tell your doctor or pharmacist if you:

  • Have allergies or bad reactions to a medication
  • Take (or plan to take) other prescription or non- prescription medications, including natural medicines. Some medications interact with melatonin. Your doctor may adjust medication doses or monitor for side effects
  • Have a history of diabetes, an autoimmune disorder, epilepsy or have ever had a seizure
  • Have a history of depression, any other psychiatric condition or thoughts of self-harm
  • Miss a menstrual period, are pregnant, breast-feeding or planning a pregnancy
  • Use alcohol or drugs. Taking melatonin together with certain substances may cause a bad reaction. Learn more at

When will the medication start to work?

Melatonin may be taken regularly or on an ‘as needed’ basis. After taking melatonin you should start to feel sleepy within 30 minutes.

Talk with your doctor if you feel that melatonin has not been helpful or if side effects are are too bothersome. Your doctor may recommend another medication.

This medication is not addictive. Do not stop taking it before talking to your doctor.

How do I take this medication?

The dose of melatonin required to improve sleep varies and is different for each person. It depends on the type of sleep disorder being treated and your response to this medication. See your doctor or pharmacist to determine the dose of melatonin that works best for you. Melatonin is best absorbed when taken on an empty stomach. When possible, use the lowest dose of melatonin that works well for you.

There are several forms of melatonin: quick-acting capsules, controlled-release (CR) tablets or capsules, liquid and sublingual or orally disintegrating tablets. Quick-acting capsules should be swallowed whole with liquid. You may also open the capsule and dissolve the contents in any preferred liquid just before use. CR tablets or capsules should be swallowed whole with liquids and should not be crushed or chewed. If you are using the sublingual or orally disintegrating tablets, place the tablet under your tongue until it is completely dissolved and absorbed (do not swallow for 2 minutes). The quick acting form of melatonin may work better for helping you fall asleep faster, while the CR form may be more beneficial for maintaining sleep overnight.

Possible common or serious side effects:

Side effects may be more common when starting a medication or after a dose increase. Talk to your doctor, nurse or pharmacist if any side effect concerns you.

  • Vivid dreams or nightmares
  • Morning or daytime drowsiness/tiredness
  • Headache
  • Dizziness
  • Stomach cramps

Contact your doctor immediately if you experience:

  • Unexplained rash
  • Symptoms of depression (prolonged low mood or sadness)
  • Mild anxiety or reduced alertness
  • Confusion or reduced alertness
  • Nausea or vomiting
  • Increased frequency of seizures in people with seizure
  • disorder (epilepsy)

What precautions should my doctor and I be aware of when taking this medication?

  • Before starting melatonin, try making small changes to sleep habits to see if you have a need for medication. For example, good sleep habits include:
    • avoiding caffeine and other substances that can disrupt sleep (alcohol, nicotine, cannabis)
    • sticking to a regular sleep/wake schedule (avoid sleeping in or taking naps)
    • powering down devices early in the evening and avoiding stimulating activities, large meals or exposure to bright lights before bedtime
    • keeping the bedroom only for sleep, free of distractions
  • Some medications may interact with melatonin, including other sleep-aides, anti-anxiety medications and several others. If you are (or begin) taking any other prescription, over-the-counter medication, natural health product or supplement, check with your doctor or pharmacist to see if they are safe to use.
  • While taking this medication, if you feel dizzy, drowsy or slowed down in the morning, do not drive a car or operate heavy machinery. Alcohol could make this worse. Try to avoid alcohol while taking melatonin.

How does this medication work?

In people who have a low level of natural melatonin, taking this hormone may shorten the time it takes you to fall asleep and increase the duration of sleep. Melatonin improves sleep difficulties by resetting the internal body clock and regulating sleep cycles. Melatonin is naturally produced in the brain in response to darkness to promote sleep at night. Melatonin levels remain low during the daytime to promote wakefulness.

What special instructions should I follow while using this medication?

  • Keep all appointments with your doctor.
  • Tell your doctor about your sleep pattern, and if you notice any effects you think may be related to taking melatonin. Your doctor will monitor your sleep and response to this medication.
  • Do not allow anyone else to use your medication.

What should I do if I forget to take a dose of this medication?

Unlike most medications used for sleep, sleep difficulties will not worsen if a dose of melatonin is missed. If you take melatonin regularly and forget to take a dose, skip the missed dose and take your next dose at its regularly scheduled time the next day. DO NOT double your next dose to try to ‘catch up’.

How do I store this medication?

Keep this medication in the original container, stored at room temperature away from moisture and heat and protected from light. Keep this medication out of reach and sight of children.

How well does the medication work in children and adolescents?

Melatonin is used to improve sleep both in children and adolescents without psychiatric conditions who have difficulty sleeping, as well as those with delayed sleep phase syndrome associated with conditions such as visual impairment, cerebral palsy, ADHD, autism or developmental delay. In children and adolescents with ADHD, melatonin may shorten the time it takes to fall asleep by 15 to 30 minutes. Evidence from adults shows a small benefit for improving sleep onset and increasing total sleep time. This medication may be helpful for people who experience jetlag from traveling, or who have trouble sleeping related to shift work.

How long should I take the medication for?

Melatonin may be taken regularly or on an ‘as-needed’ basis for as long as sleep problems continue. Melatonin remains effective for promoting sleep even when taken regularly for extended periods of time. Whenever possible, use melatonin for the shortest duration possible. You may stop it occasionally to see if melatonin is still needed. Due to the complex nature of sleep disorders, children and adolescents should remain under a doctor’s care during melatonin treatment.

TIP: Visit the Kelty Mental Health website for more tips on building healthy sleep habits.

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