Melatonin

Jet lag
Jet lag is caused by a disturbance to the body’s natural 24-hour rhythm when travelling rapidly between different time zones. Jet lag often lasts a few days but may last up to a week or more. It can cause sleep disturbances, daytime tiredness, loss of concentration and motivation, headache, irritability, reduced appetite, and bloating. It is often unpleasant, and sometimes debilitating, affecting both business and holiday travel. Severity varies from person to person and on the number of time zones crossed, tending to be more severe in older people, and with flights heading East, that cause a ‘gain’ in time.

It is often quoted that it takes one day per hour of time zone difference for the body to adjust to a new time zone, but this can vary. If travelling to a different time zone for only a few days, some people may cope better by maintaining their body clock, sleep and meal times, to their original time zone.

Melatonin for jet lag
Melatonin was shown to be effective at preventing or reducing jet lag in 8 out of 10 trials reviewed by The Cochrane Collaboration in 2002. The benefit was seen when crossing more than 5 time zones. However, more recent research has given varied results. Melatonin is most effective if crossing at least 2 time zones and is of special benefit if travelling Eastwards. Its effects are improved if combined with bright light at appropriate times of the day (see below).

How to take melatonin 3mg tablets for jet lag
For adults only – start the tablets on arrival at your destination, not before. Take the first dose (one 3mg tablet) at your usual bedtime in the new time zone. Melatonin should encourage sleep but it is not a sleeping tablet. Further doses are taken at bedtime on the following days for up to a maximum of five days. Tablets should not be taken before 8 pm or after 4 am. The dose can be increased to two tablets if one tablet is not effective. Tablets should be swallowed whole with water, at least 2 hours before or after food.

If you forget to take the dose at bedtime and wake during the night you may take the forgotten dose, but at no later than 4 am. Do not take a double dose to make up for a missed dose.

The 5-day course can be repeated for further episodes of jet lag, but a maximum of 16 courses for jet lag can be taken per year.

If you have taken more than recommended, please contact your doctor, hospital, or pharmacy. Common symptoms of overdose are drowsiness, headache, dizziness, and nausea.

There should be no withdrawal symptoms or harmful effects on stopping melatonin tablets, and the course can be stopped before 5 days if jet lag symptoms settle more quickly.

How to reduce jet lag without medication

• Before you travel try going to bed at a time closer to the destination bedtime. Try to make sure you have enough sleep in the days before you travel.
• Keep as calm and relaxed as possible during travel.
• Drink plenty to keep hydrated, especially during the flight.
• Avoid alcohol.
• Move around during the flight when you can.
• Adjust the time on your watch to the destination time at the start of the flight.
• Sleep during the journey only during ‘night time hours’ on destination time.
• On arrival try to sleep and eat at destination times.
• Stay in a dark bedroom during the night, even if you are awake.
• Try to avoid naps during the day.
• Spend time out of doors, especially in the afternoons if travelling West, and in the mornings if travelling East, as bright natural light helps with adjustment. Alternatively, use a SAD light at these times.

Can anyone take melatonin?
Most people can take melatonin, although people with some pre-existing medical conditions or those taking certain medicines should not take it. Suitability is assessed with a short health questionnaire which is part of the Dr Fox ordering process. Further information is in the patient information leaflet supplied with the tablets. Melatonin is not suitable for under 18s.

Warnings/cautions
Talk to your doctor before taking melatonin medication, if the following apply:

• Epilepsy – may cause more fits.
• Autoimmune diseases including rheumatoid arthritis, thyroid disease, and coeliac disease, where an illness is caused by antibodies to healthy body organs.
• Diabetes or impaired glucose tolerance (pre-diabetes) – blood sugar levels may increase.
• Impaired kidney function or liver function.

Smoking may reduce the effect of melatonin medication as smoking can increase the breakdown of melatonin by the liver.

Children and adolescents – not suitable for under 18 years, safety and efficacy are unknown.

Other medicines
The following medications increase the effect of melatonin and should not be taken at the same time:

• Fluvoxamine for depression, OCD (obsessive-compulsive disorder).
• Psoralen as part of PUVA light treatment for skin conditions like psoriasis.
• Cimetidine is rarely used for stomach acid.
• Oestrogen in combined contraceptives or HRT (hormone replacement).
• Quinolone antibiotics are rarely used, e.g. ciprofloxacin, and moxifloxacin.
• Other sleeping tablets or remedies.

The following medications decrease the effect of melatonin and should not be taken at the same time:

• Rifampicin antibiotic for tuberculosis.
• Carbamazepine for epilepsy, bipolar disorder, and trigeminal neuralgia.

Warfarin may be affected by melatonin, but newer NOAC anticoagulants like dabigatran and apixaban are not affected. Discuss with your GP.

Melatonin tablets with alcohol and food
Alcohol should NOT be taken whilst taking melatonin. Alcohol can impair sleep and potentially worsen certain symptoms of jet lag (e.g. concentration, headache, morning fatigue).

Melatonin should not be taken within 2 hours of food.

Pregnancy, breastfeeding, and fertility
Melatonin should not be taken if you are pregnant or breastfeeding think you may be pregnant or are planning to have a baby. Melatonin is found in breast milk and crosses the placenta to the foetus. The effects on babies and the unborn are unknown and therefore it is not recommended. Women who might become pregnant MUST use effective contraception if taking melatonin.

Operating machinery and driving

Melatonin can decrease alertness for several hours after intake – do NOT drive, cycle, or operate machinery after taking.

Side effects
Melatonin can cause side effects, but they do not affect everyone.

Serious side effects
Contact a doctor immediately if you develop any of these uncommon but serious side effects:

• Chest pain (1 in 100).
• Palpitations, fainting, disorientation, visual symptoms (1 in 1000).
• Allergic reactions include swelling of the tongue and mouth.

Rarely (1 in 1000) there can be effects on the blood leading to fewer white blood cells or platelets and this may cause bruising, bleeding or blood in the urine, or an increased infection risk. Contact a doctor if you develop any of these symptoms.

Non-serious side effects
Up to 1 in 10 people may experience headaches or daytime drowsiness. Sometimes women, and occasionally men, may experience milk leakage from the breasts. More information on side effects is found in the manufacturer’s patient information leaflet.

Other uses of melatonin
Dr Fox only supplies melatonin for jet lag. Melatonin is also licensed in the UK as a slow-release 2mg tablet (Circadin) for short-term treatment of insomnia in adults over 55. There is also an unlicensed, but recognised use to treat insomnia in patients with learning disability or challenging behaviours.

Melatonin has been studied as a treatment for a variety of other conditions. These include Gastroesophageal reflux disease (GERD), as a support to cancer treatments (e.g. radiotherapy, chemotherapy), endometriosis, high blood pressure, menstrual pain, general insomnia, shift work-related insomnia, frequent urination at night (nocturia), migraine prevention, anxiety before surgery, sunburn prevention, jaw pain from temporomandibular joint problems, age-related macular degeneration in the eyes, winter depression (SAD), Alzheimer’s disease, tinnitus, and COVID-19. Unfortunately, many of the studies have been in very small numbers of patients and have been unreliable. Dr Fox is unable to supply melatonin for any of these other conditions.