Drug interactions
Carbamazepine + Loratadine
Severity: Minor
Carbamazepine and Loratadine: minor interaction.
Last updated Sources: US FDA label
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
Carbamazepine induces CYP3A4 and CYP2D6, which can lower loratadine and desloratadine concentrations and reduce antihistamine efficacy. The effect is mainly reduced symptom control, as loratadine has a wide safety margin.
What this interaction means in plain words
Carbamazepine 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.
Carbamazepine belongs to Central Nervous System; Loratadine belongs to Respiratory.
Why it happens
Carbamazepine induces CYP3A4 and related enzymes, increasing loratadine metabolism.
What to do
No empiric dose change is needed. If allergy symptoms are poorly controlled, consider a higher dose within labeling or a non-CYP-dependent antihistamine such as fexofenadine.
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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References
- Carbamazepine - FDA drug label (DailyMed) — openFDA / DailyMed
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 Carbamazepine
- Artemether / lumefantrine + Carbamazepine Contraindicated
- Cabotegravir + Carbamazepine Contraindicated
- Carbamazepine + Delamanid Contraindicated
- Carbamazepine + Dienogest / estradiol valerate Contraindicated
- Carbamazepine + Doravirine Contraindicated
- Carbamazepine + Elbasvir / grazoprevir Contraindicated
Frequently asked questions
Can I take Carbamazepine with Loratadine?
MediHelp rates the interaction as minor. Carbamazepine 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. Carbamazepine induces CYP3A4 and CYP2D6, which can lower loratadine and desloratadine concentrations and reduce antihistamine efficacy. The effect is mainly reduced symptom control, as loratadine has a wide safety margin.
How serious is the interaction between Carbamazepine 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 empiric dose change is needed. If allergy symptoms are poorly controlled, consider a higher dose within labeling or a non-CYP-dependent antihistamine such as fexofenadine.
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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