Drug interactions
Melatonin + Phendimetrazine
Severity: Minor
Melatonin and Phendimetrazine: minor 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
Melatonin promotes sleepiness while phendimetrazine is a stimulant anorectic that can cause insomnia and agitation. The two have opposing effects, so each may blunt the intended action of the other, but no meaningful harmful interaction is established.
What this interaction means in plain words
Melatonin and Phendimetrazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Opposing pharmacodynamic effects on arousal; no established pharmacokinetic mechanism.
What to do
No dose change is needed. Be aware that phendimetrazine-related insomnia may reduce the benefit of melatonin, and review dosing time if sleep is disturbed.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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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
Frequently asked questions
Can I take Melatonin with Phendimetrazine?
MediHelp rates the interaction as minor. Melatonin and Phendimetrazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Melatonin promotes sleepiness while phendimetrazine is a stimulant anorectic that can cause insomnia and agitation. The two have opposing effects, so each may blunt the intended action of the other, but no meaningful harmful interaction is established.
How serious is the interaction between Melatonin and Phendimetrazine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No dose change is needed. Be aware that phendimetrazine-related insomnia may reduce the benefit of melatonin, and review dosing time if sleep is disturbed.
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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