Drug interactions
Clemastine + Phentermine
Severity: Minor
Clemastine and Phentermine: 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
Clemastine causes sedation while phentermine is a sympathomimetic stimulant, so their effects on alertness may offset one another. No significant harmful interaction is established and the net effect varies between patients.
What this interaction means in plain words
Clemastine and Phentermine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Clemastine belongs to Respiratory; Phentermine belongs to Central Nervous System.
Why it happens
Opposing pharmacodynamic effects on CNS arousal; no established pharmacokinetic mechanism.
What to do
No routine intervention is required; advise the patient to judge their own alertness before driving or operating machinery.
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 Clemastine
Other interactions of Phentermine
- Isocarboxazid + Phentermine Contraindicated
- Linezolid + Phentermine Contraindicated
- Phenelzine + Phentermine Contraindicated
- Phentermine + Procarbazine Contraindicated
- Phentermine + Rasagiline Contraindicated
- Phentermine + Selegiline Contraindicated
Frequently asked questions
Can I take Clemastine with Phentermine?
MediHelp rates the interaction as minor. Clemastine and Phentermine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Clemastine causes sedation while phentermine is a sympathomimetic stimulant, so their effects on alertness may offset one another. No significant harmful interaction is established and the net effect varies between patients.
How serious is the interaction between Clemastine and Phentermine?
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 routine intervention is required; advise the patient to judge their own alertness before driving or operating machinery.
What other medicines interact with Clemastine?
MediHelp also lists interactions of Clemastine with, for example, Alfentanil, Benzhydrocodone / acetaminophen, Buprenorphine buccal. The full list is on the Clemastine page.
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