Drug interactions
Loratadine + Zafirlukast
Severity: Minor
Loratadine and Zafirlukast: 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
Zafirlukast is a CYP3A4 and CYP2C9 inhibitor in vitro, but it has little clinical effect on CYP3A4 substrates. Any change in loratadine exposure is expected to be minimal.
What this interaction means in plain words
Loratadine and Zafirlukast have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Loratadine belongs to Respiratory; Zafirlukast belongs to Respiratory.
Why it happens
Weak in vitro CYP3A4 inhibition by zafirlukast; clinical relevance is not established.
What to do
No action is generally needed; monitor for increased drowsiness.
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
Other interactions of Zafirlukast
- Pimozide + Zafirlukast Contraindicated
- Lomitapide + Zafirlukast Major
- Nilotinib + Zafirlukast Major
- Warfarin + Zafirlukast Major
- Apalutamide + Zafirlukast Moderate
- Carbamazepine + Zafirlukast Moderate
Frequently asked questions
Can I take Loratadine with Zafirlukast?
MediHelp rates the interaction as minor. Loratadine and Zafirlukast have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Zafirlukast is a CYP3A4 and CYP2C9 inhibitor in vitro, but it has little clinical effect on CYP3A4 substrates. Any change in loratadine exposure is expected to be minimal.
How serious is the interaction between Loratadine and Zafirlukast?
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 action is generally needed; monitor for increased drowsiness.
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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