Drug interactions
Loratadine + Phenobarbital
Severity: Minor
Loratadine and Phenobarbital: 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
Phenobarbital is an enzyme inducer and may reduce loratadine exposure, possibly weakening symptom control. Additive drowsiness is also possible.
What this interaction means in plain words
Loratadine and Phenobarbital 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
Phenobarbital induces CYP3A4 and other enzymes, increasing loratadine clearance.
What to do
Monitor for reduced antihistamine efficacy and sedation; switch antihistamine or adjust dose if control is inadequate.
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 Loratadine
- Acrivastine + Loratadine Moderate
- Amobarbital + Loratadine Moderate
- Fentanyl + Loratadine Moderate
- Isocarboxazid + Loratadine Moderate
- Levoketoconazole + Loratadine Moderate
- Loratadine + Mavacamten Moderate
Frequently asked questions
Can I take Loratadine with Phenobarbital?
MediHelp rates the interaction as minor. Loratadine and Phenobarbital have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Phenobarbital is an enzyme inducer and may reduce loratadine exposure, possibly weakening symptom control. Additive drowsiness is also possible.
How serious is the interaction between Loratadine and Phenobarbital?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for reduced antihistamine efficacy and sedation; switch antihistamine or adjust dose if control is inadequate.
What other medicines interact with Loratadine?
MediHelp also lists interactions of Loratadine with, for example, Acrivastine, Amobarbital, Fentanyl. The full list is on the Loratadine page.
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