Lithium safety
Lithium should always be prescribed by brand as bioavailability can vary widely between products. Lithium salts – lithium carbonate (used in solid dose preparations) and lithium citrate (used in liquid preparations) – are also not dose equivalent.7
Lithium needs to be monitored closely, with plasma levels measured weekly after initiating treatment, or after every dose change until levels are stable. It should then be monitored every three months for the first year and then six monthly.
Higher risk patients (eg older people, those taking medicines that interact with lithium, those with impaired renal or thyroid function, raised calcium levels, or those with poor symptom control or medicines adherence) should continue with three-monthly checks.8
People taking lithium who develop diarrhoea or vomiting, or become acutely ill for any reason, should seek medical attention. Lithium patients should maintain fluid intake, particularly after sweating (eg through exercise or fever), if they are immobile for long periods or if they develop a chest infection or pneumonia.
People taking lithium should also avoid non-steroidal inflammatory drugs (NSAIDs) as they can increase blood lithium levels. If NSAIDs need to be prescribed, then they should be taken on a regular basis (not ‘as required’ or ‘prn’) and the lithium levels monitored monthly until stable, and then every three months.
Stopping lithium should see the dose tapered down over at least a month to three months, even if an alternative mood stabiliser has been started. During dose reduction and for at least three months after stopping lithium, the patient should be monitored for early signs of mania or depression.