Drug interactions
Ketoconazole + Loratadine
Severity: Minor
Ketoconazole and Loratadine: 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
Ketoconazole strongly inhibits CYP3A4 and raises plasma levels of loratadine and desloratadine several-fold. Studies showed no meaningful ECG changes or clinical adverse effects, so the interaction is generally of limited clinical significance.
What this interaction means in plain words
Ketoconazole and Loratadine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Ketoconazole belongs to Anti Fungals; Loratadine belongs to Respiratory.
Why it happens
Inhibition of CYP3A4-mediated (and CYP2D6-mediated) metabolism of loratadine by ketoconazole.
What to do
No routine dose adjustment is required at standard loratadine doses. Counsel the patient to report excessive sedation or palpitations.
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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Frequently asked questions
Can I take Ketoconazole with Loratadine?
MediHelp rates the interaction as minor. Ketoconazole and Loratadine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Ketoconazole strongly inhibits CYP3A4 and raises plasma levels of loratadine and desloratadine several-fold. Studies showed no meaningful ECG changes or clinical adverse effects, so the interaction is generally of limited clinical significance.
How serious is the interaction between Ketoconazole and Loratadine?
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 dose adjustment is required at standard loratadine doses. Counsel the patient to report excessive sedation or palpitations.
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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