Piracetam

Piracetam is a cyclic derivative of gamma-aminobutyric acid (GABA). It is thought to improve the flexibility of cell membranes and the flow of blood through small vessels, although the exact way it works in the brain is not fully understood. In the UK, its single licensed indication is cortical myoclonus: sudden, involuntary muscle jerks that start in the outer layer of the brain, which may follow lack of oxygen, head injury or certain inherited conditions. According to the SmPC, it is given together with other anti-myoclonic medicines, whatever the underlying cause.

Two tablet strengths are offered: 400 mg and 800 mg, each in packs of 30, 60, 90, 120, 180, 270 and 360. The UK-licensed tablet is 800 mg; the 400 mg strength is not licensed in the UK and is an imported generic. The medicine is sometimes promoted as a "nootropic" or memory enhancer, but the UK licence covers myoclonus only, and memory improvement is not an approved use.

Doses for myoclonus are large. The SmPC advises starting at 7.2 g a day and increasing by 4.8 g every three to four days, up to a maximum of 24 g daily, split into two or three doses. Once the jerks are controlled, attempts are made to reduce other anti-myoclonic drugs, and withdrawal of the medicine itself should be gradual, to avoid a sudden relapse or seizures. Because the medicine is cleared by the kidneys, the daily amount is lowered when kidney function is reduced. With 400 or 800 mg tablets, licensed doses would mean a large number of tablets each day; the prescriber works out the practical regimen.

Piracetam is a prescription-only medicine (POM). The UK brand is Nootropil, currently held by Advanz Pharma, and use is generally guided by a neurologist, with prescriptions often continued by the GP once a stable dose is reached.

Piracetam is contraindicated in severe kidney impairment, after a brain haemorrhage, in Huntington's disease and in anyone allergic to piracetam or related pyrrolidone compounds. Because it reduces platelet clumping, caution is needed in people with bleeding disorders, those facing major surgery and those taking anticoagulants or antiplatelet drugs. Kidney function is usually checked before treatment and at intervals in older patients, since the dose depends on it. Confusion, irritability and disturbed sleep have been reported when it was taken together with thyroid hormones.

The most commonly reported reactions are nervousness, restlessness and hyperactivity, along with weight gain. Some people experience drowsiness, low mood or weakness, and digestive upset such as nausea, abdominal pain or diarrhoea can occur at higher doses. Allergic skin reactions are uncommon. At very high daily totals, the tablets contribute a measurable amount of sodium, which matters for people on a salt-restricted diet. Any new or worsening jerks, or a seizure, should be reported to the neurologist straight away rather than adjusting the dose at home.

It is not recommended in pregnancy or while breastfeeding, and it can affect alertness, so take care with driving. Your doctor decides whether this medicine is appropriate and at what dose.