Lithium in children: watch kidney, thyroid and gut, and keep reporting

Design

Case-control disproportionality analysis of spontaneous reports in VigiBase, 1968 to October 2023

Population

29,897 lithium-related reported adverse reactions and a second-generation antipsychotic comparison group, people older than 2 years

Primary outcome

Proportion and distribution of reported adverse reactions by organ class and age

Effect

In children, higher proportion of renal, endocrine, gastrointestinal, skin and cardiac reports with lithium than with antipsychotics (proportional reporting ratios)

Researchers analysed individual case safety reports in VigiBase, the WHO database, from 1968 to October 2023 for people older than 2 years given lithium or second-generation antipsychotics. The lithium group contained 29,897 reported adverse reactions, classified by MedDRA and compared across age groups by proportional reporting ratios.

In children, lithium was associated with a higher proportion of renal, endocrine, gastrointestinal, skin and cardiac reactions than the antipsychotics, and thyroid reactions were proportionally more common in children. Serious outcomes such as renal failure were proportionally more frequent in older adults than in children. Antipsychotics showed more weight-related reports in children, and more diabetes and cardiovascular events in adults.

Spontaneous reports cannot give incidence, since the denominator is unknown, and reporting is influenced by awareness, publicity and why a drug is used. The data are a prompt for monitoring, not evidence that lithium is more dangerous than antipsychotics.

• Check renal function, thyroid function and electrolytes before starting lithium in a child, and at intervals afterwards according to local protocol
• Ask about thirst, polyuria, nausea, diarrhoea, tremor and skin changes at each review
• Review interacting drugs and illnesses that cause dehydration, since they can raise lithium levels
• Use serum levels as usual and act on symptoms of toxicity
• Report suspected reactions through pharmacovigilance systems

Why it matters

It points to the organ systems where monitoring is most likely to pick up a problem in a young patient.

Don't overread it

Spontaneous reports cannot give incidence or show that lithium is riskier than antipsychotics, and reporting is influenced by many factors.

The statistics, in plain English

A proportional reporting ratio compares the share of a drug's reports that concern one reaction with the share for other drugs. A higher ratio means the reaction makes up more of that drug's reports, not that it is more likely to occur in a patient. Reports are voluntary and incomplete, and children on lithium and antipsychotics differ in diagnosis and severity.

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