Lithium and Hypothyroidism: is the FAERS signal real?
Lithium ↔ Hypothyroidism
Lithium concentrates in the thyroid and interferes with the synthesis and release of thyroid hormone, so it commonly causes hypothyroidism and, less often, goitre or hyperthyroidism. The effect is dose-related, is more common in women and in those with pre-existing thyroid antibodies, and is managed by thyroid-hormone replacement without necessarily stopping the lithium. The 224 co-reports (PRR 5.9) reflect both the real effect and the fact that lithium is typically taken for years, giving the thyroid change time to emerge and be detected on routine testing.
Regulatory basis: lithium prescribing information (thyroid dysfunction; routine thyroid-function monitoring). Established lithium-thyroid literature.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Hypothyroidism emerges during long-term therapy and responds to hormone replacement |
| Strength | partial | PRR 6 on a modest co-report count |
| Consistency | met | Reproduced across decades of lithium-thyroid studies |
| Specificity | met | A recognised lithium effect, though other drugs can also cause hypothyroidism |
| Biological gradient | met | Dose-related and commoner with thyroid antibodies and in women |
| Plausibility | met | Inhibition of thyroid-hormone synthesis/release is the proposed mechanism |
| Coherence | met | Coheres with the labelled routine thyroid monitoring |
| Experiment | partial | Dechallenge (and/or replacement therapy) manages it; no randomized trial |
| Analogy | met | Analogous to hypothyroidism from amiodarone and interferon |
This page's own qualitative read, not an automated/citation-gated assessment.