Lithium in young people: renal and thyroid monitoring belongs in the plan from the start

Design

Case–non-case disproportionality analysis of spontaneous reports

Population

VigiBase reports (1968–2023) for lithium and second-generation antipsychotics in people over 2 years

Primary outcome

Proportional reporting of adverse reaction types by age group

Effect

In children, lithium reports showed proportionally more renal, endocrine, gastrointestinal, skin and cardiac reactions

Lithium is used in adolescents with bipolar disorder, but safety data in children are sparse. This study analysed individual case safety reports in the WHO VigiBase database from 1968 to 2023 involving people older than two years, comparing nearly 30,000 lithium-related reactions with those reported for second-generation antipsychotics, across age groups.

In children, lithium reports carried a higher proportion of renal, endocrine, gastrointestinal, skin and cardiac reactions than antipsychotic reports. Thyroid reactions were proportionally more common in children on lithium, while renal failure featured more in older adults. Antipsychotic reports in children were dominated by weight-related effects, and in adults by diabetes and cardiovascular events.

Spontaneous reports cannot give rates, and reporting is shaped by awareness and by who receives each drug. The practical message is still clear: when lithium is chosen for a young person, renal and thyroid monitoring should be scheduled from the start, and families told what gastrointestinal and skin effects to report. The comparison is not a reason to prefer antipsychotics, whose metabolic burden in young people is substantial.

• Check baseline renal function, thyroid function and calcium before starting lithium in a young person.
• Schedule repeat renal and thyroid tests at regular intervals, at least every six months.
• Tell families which gastrointestinal, skin and cardiac symptoms to report.
• Weigh lithium's renal and thyroid risks against antipsychotics' weight and metabolic risks together.
• Report suspected adverse reactions in children; paediatric data remain sparse.

Why it matters

Paediatric lithium safety has rested on adult data; these reports point to the organ systems to watch in children specifically.

Don't overread it

Disproportionality in spontaneous reports shows reporting patterns, not how often reactions occur.

The statistics, in plain English

A proportional reporting ratio compares how often a reaction appears among reports for one drug against reports for another. It cannot give the risk to an individual, because nobody knows how many people took each drug without reporting anything.

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