Melatonin After Shoulder Surgery Folheto

If you have had shoulder surgery with us, or are about to, you may have been given a prescription for melatonin alongside your painkillers. This page explains why we prescribe it, what it does and does not do, and how to take it.

Why you have been given melatonin

Sleep is one of the hardest parts of the first few weeks after shoulder surgery. The shoulder aches more lying down, you cannot get into your usual position, and the sling makes settling awkward. Broken sleep then makes the pain feel worse the next day. Our page on sleep, pain and recovery covers the practical side of that: positioning, timing your painkillers, and sleep habits.

We now routinely prescribe melatonin after shoulder surgery because a good-quality trial in keyhole rotator cuff repair found that it improved sleep in the early weeks, and that patients who took it went on to report better shoulder function and used fewer strong painkillers in the months that followed. Melatonin is gentle, it is not habit-forming, and it does not interact with pain medication the way conventional sleeping tablets do. For a temporary problem with a predictable end, that is a good trade-off.

What melatonin is

Melatonin is a hormone your own body makes at night, released by a small gland in the brain once it gets dark. It is the signal that tells the rest of the body it is night-time. The tablet is a synthetic copy of that hormone.

It is not a sedative. A sleeping tablet forces sleep on you; melatonin nudges the body clock and makes falling asleep, and staying asleep, easier. That is why it is usually taken an hour or so before bed rather than at the moment you want to be asleep, and why it works best as part of a regular bedtime routine.

What the evidence shows

The shoulder trial. In 2024 the Rothman Orthopaedic Institute in Philadelphia published a randomised trial of 80 patients having keyhole rotator cuff repair. Half took 5 mg of melatonin an hour before bed every night for six weeks, starting the day of surgery; the other half followed standard sleep-hygiene advice. Those taking melatonin had measurably better sleep at six weeks, rated their sleep quality higher out to six months, scored higher on a standard shoulder-function questionnaire at four and six months, and were using fewer opioid painkillers at four months. No side effects were reported in either group.

It is one trial, from one centre, and the patients knew which group they were in, so the result should be read as encouraging rather than definitive. It is, however, the best evidence available for exactly the situation you are in.

Other operations. Melatonin has been tested after many kinds of surgery. Pooling ten trials and 725 patients, it produced a small improvement in sleep quality after surgery overall. After hip and knee replacement, several placebo-controlled trials found little or no benefit beyond the first few nights. So melatonin is not a universal fix, and we do not claim it is. The shoulder result is the most convincing, which is why we use it there.

Sleep improves anyway. It helps to know the natural course. After rotator cuff repair, sleep is usually at its worst around the two-week mark, clearly better by six weeks to three months, and back to normal for most people by six months, and it stays that way years later. Melatonin is there to make those first weeks easier. It is not a long-term treatment and you will not need it once the shoulder has settled.

How we prescribe it

Dose: 2 mg to 5 mg, depending on your circumstances; your script will say which.
When: about an hour before your usual bedtime, at roughly the same time each night.
How long: from the night of surgery, or your first night home, for around six weeks, which is the period the trial covered. Then simply stop; there is no need to taper off.
Why a script: in Australia melatonin is a prescription medicine for most adults. The only over-the-counter form, a 2 mg slow-release tablet from a pharmacist, is approved for people aged 55 and over with insomnia. Because the dose and the reason are different after surgery, we write a script so that you get the right form.

Take it alongside, not instead of, the other things that help: sleeping propped up for the first couple of weeks, wearing your sling at night as instructed, taking your regular painkillers on schedule so they are working before you lie down, and ice in the evening.

Side effects and cautions

Melatonin is well tolerated by most people. The commonest complaints are feeling a little groggy in the morning, vivid dreams, headache or mild nausea. Morning grogginess usually settles by taking the tablet a bit earlier in the evening or dropping to the lower dose. It is not addictive and there is no withdrawal when you stop.

You will not be driving in the early weeks after shoulder surgery in any case; once you are cleared to drive, be aware of morning drowsiness for the first few days back behind the wheel. Avoid alcohol on the nights you take it.

Tell us if any of these apply, so we can adjust the plan:

you take warfarin or another blood thinner, as melatonin can affect clotting tests
you have epilepsy or an autoimmune condition
you are pregnant or breastfeeding
you already take a sleeping tablet or an antidepressant

What to expect

Do not expect to be knocked out on the first night. The benefit in the trial showed up over weeks, as sleep gradually consolidated, rather than as a dramatic change on night one. If pain is what is waking you, the fix is pain control and positioning first; melatonin will not override a shoulder that is not comfortable.

If it does not seem to help you, or you would rather not take it, that is fine. It is an optional part of your recovery, not an essential one. Tell us at your review and we will take it off your list.

The bottom line

Poor sleep after shoulder surgery is common, temporary, and worth treating. One good trial found that six weeks of melatonin makes the early weeks easier and may pay off in function later; the drug is gentle and non-addictive. That is why it is on your prescription.

When to call us

Pain that is getting worse rather than better, or that your medications are not controlling
Daytime drowsiness or confusion that is more than mild
A rash, swelling of the face or lips, or difficulty breathing after a dose: stop the tablets and go to the emergency department
The usual wound and general warning signs listed on the sleep, pain and recovery page