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Oenothera biennis
Severe· moderate-evidence
Avoid this combination unless your prescriber explicitly approves it with appropriate monitoring.
Evening primrose oil may lower the seizure threshold, increasing seizure risk in patients taking phenothiazines.
GLA in evening primrose oil may reduce seizure threshold, and phenothiazines also lower seizure threshold, creating additive risk.
Source: Natural Medicines Database · Reviewed April 2026
Evening Primrose + Phenothiazines (Chlorpromazine): high risk. Avoid this combination unless your prescriber explicitly approves it with appropriate monitoring. Evening primrose oil may lower the seizure threshold, increasing seizure risk in patients taking phenothiazines.
GLA in evening primrose oil may reduce seizure threshold, and phenothiazines also lower seizure threshold, creating additive risk.
Do not stop either abruptly on your own. Talk to your prescriber or pharmacist promptly — bring this page to your appointment.
Educational information only — not medical advice. Always verify with a healthcare professional.