Drug interactions
Melatonin + Primidone
Severity: Moderate
Melatonin and Primidone: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Primidone, partly metabolized to phenobarbital, is sedating and may add to melatonin drowsiness. Its enzyme-inducing effect may also lower melatonin concentrations and reduce its efficacy.
What this interaction means in plain words
Melatonin and Primidone can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Melatonin belongs to Gastrointestinal Tract; Primidone belongs to Central Nervous System.
Why it happens
Additive CNS depression plus induction of CYP1A2-mediated melatonin metabolism.
What to do
Monitor for sedation and for loss of melatonin effect. Adjust the melatonin dose according to response.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Melatonin
- Fluvoxamine + Melatonin Major
- Alfentanil + Melatonin Moderate
- Belladonna and opium + Melatonin Moderate
- Buprenorphine buccal + Melatonin Moderate
- Butabarbital + Melatonin Moderate
- Butalbital + Melatonin Moderate
Other interactions of Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Melatonin with Primidone?
MediHelp rates the interaction as moderate. Melatonin and Primidone can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Primidone, partly metabolized to phenobarbital, is sedating and may add to melatonin drowsiness. Its enzyme-inducing effect may also lower melatonin concentrations and reduce its efficacy.
How serious is the interaction between Melatonin and Primidone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for sedation and for loss of melatonin effect. Adjust the melatonin dose according to response.
What other medicines interact with Melatonin?
MediHelp also lists interactions of Melatonin with, for example, Fluvoxamine, Alfentanil, Belladonna and opium. The full list is on the Melatonin page.
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