Can Lithium Cause Headaches?
Yes, lithium can cause headaches as an adverse effect, with headache being listed among the miscellaneous reactions in the FDA drug label. 1
Direct Evidence of Headache as a Side Effect
The FDA-approved drug label for lithium explicitly lists headache among the miscellaneous adverse reactions unrelated to dosage. 1 This establishes headache as a recognized side effect of lithium therapy, though it is not classified among the more serious dose-dependent toxicity symptoms.
Context of Headache in Lithium's Adverse Effect Profile
Mild vs. Serious Adverse Effects
Headache falls into the category of miscellaneous reactions that are unrelated to serum lithium dosage, distinguishing it from the more serious dose-dependent toxicity symptoms like dizziness, ataxia, and blurred vision that occur at higher lithium levels. 1
The FDA label indicates that headache occurs alongside other miscellaneous effects such as fatigue, lethargy, transient scotomata, and metallic taste. 1
Serotonergic Syndrome Consideration
When lithium is used concomitantly with certain medications (monoamine oxidase inhibitors, sumatriptan, or tryptophan), a "serotonergic syndrome" can occur, which in mild cases is characterized by headache, nausea, sweating, and dizziness. 2
This represents a more serious drug interaction scenario where headache is a warning sign of potential toxicity, though this is rare. 2
Clinical Implications for Monitoring
When to Be Concerned
Headache alone is generally a benign side effect that does not require cessation of therapy, unlike the early signs of lithium toxicity (diarrhea, vomiting, drowsiness, muscular weakness, lack of coordination) which warrant immediate attention. 1
If headache occurs with other neurological symptoms such as visual changes, this could indicate pseudotumor cerebri (increased intracranial pressure and papilledema), a serious complication requiring discontinuation of lithium. 1
Monitoring Requirements
Regular monitoring should include assessment of clinical symptoms, with patients educated about distinguishing benign side effects like headache from early signs of toxicity. 3
Serum lithium concentrations should be monitored twice weekly during acute stabilization and every 3-6 months once stable. 2, 3
Common Pitfalls to Avoid
Do not dismiss headache if accompanied by visual symptoms (blurred vision, visual field changes, papilledema), as this may indicate pseudotumor cerebri requiring immediate discontinuation. 1
Do not confuse simple headache with serotonergic syndrome, which requires assessment of concurrent medications and presents with multiple symptoms including nausea, sweating, and dizziness. 2
Be aware that while lithium is used to treat certain headache disorders (cluster headaches), it can paradoxically cause headaches as a side effect. 4, 5, 6, 7