Cinnarazine drug interactions
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cinnarizine drug interactions
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cinnarizine pharmacology CNS depressants antihistamine interactions
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The retrieved results are limited on cinnarizine-specific interactions. Here is a comprehensive answer synthesized from both retrieved content and established pharmacological knowledge.
Cinnarizine Drug Interactions
Cinnarizine is a first-generation antihistamine (H₁-blocker) with additional calcium channel blocking and anti-dopaminergic properties. Its interaction profile reflects all three mechanisms.
CNS Depressants (Major Interactions)
| Drug Class | Interaction | Clinical Consequence |
|---|---|---|
| Alcohol | Additive CNS depression | Enhanced sedation, impaired psychomotor function |
| Benzodiazepines | Additive CNS depression | Excessive sedation, respiratory depression |
| Opioids / Analgesics | Additive CNS depression | Increased sedation, risk of respiratory compromise |
| Barbiturates | Additive CNS depression | Excessive sedation |
| Antipsychotics | Additive CNS/dopaminergic blockade | Worsened extrapyramidal effects (EPSs) |
| Antidepressants (TCAs) | Additive anticholinergic + sedative effects | Dry mouth, urinary retention, confusion, arrhythmias |
| Hypnotics / Sedatives | Additive CNS depression | Prolonged sedation |
As noted in guidelines on first-generation H₁-antihistamines, "many interactions with alcohol and other drugs, such as analgesics, hypnotics, sedatives, and mood-elevating drugs, have been described" (Definition, Classification, Diagnosis, and Management of Urticaria, p. 22).
Dopaminergic Drugs (Clinically Significant)
- Levodopa / Dopamine agonists: Cinnarizine blocks dopamine receptors (D2) and can antagonize the effect of levodopa in Parkinson's disease. Cinnarizine is itself a known cause of drug-induced parkinsonism and should be avoided or used with extreme caution in patients on antiparkinsonian therapy.
- Metoclopramide: Combined dopamine blockade increases risk of extrapyramidal effects (acute dystonia, akathisia, tardive dyskinesia).
Cardiovascular Drugs
| Drug | Interaction |
|---|---|
| Antihypertensives | Additive hypotensive effect due to calcium channel blocking activity of cinnarizine |
| Other calcium channel blockers (e.g., amlodipine, verapamil) | Potentiated vasodilation and hypotension |
| QT-prolonging drugs (e.g., amiodarone, antipsychotics, certain antibiotics) | Theoretical additive QT prolongation risk |
Anticholinergic Drugs
Cinnarizine has mild anticholinergic properties. Combining it with other anticholinergic agents (e.g., tricyclic antidepressants, oxybutynin, antimuscarinics) increases the risk of:
- Dry mouth, constipation, urinary retention
- Confusion and delirium (especially in elderly patients)
- Tachycardia
Special Considerations
- Elderly patients: Heightened risk of falls, sedation, anticholinergic burden, and drug-induced parkinsonism.
- Driving and machinery: Sedation is enhanced markedly by any CNS-active co-medication; patients should be warned explicitly.
- Alcohol: Even small amounts can substantially amplify sedation.
- REM sleep: First-generation antihistamines (including cinnarizine) suppress REM sleep; co-administration with other sleep-altering agents worsens this effect.
Summary Table
| Category | Key Drugs | Risk |
|---|---|---|
| CNS depressants | Alcohol, benzodiazepines, opioids, barbiturates | Excessive sedation |
| Dopaminergic agents | Levodopa, dopamine agonists | Reduced efficacy of antiparkinsonian therapy |
| Dopamine antagonists | Metoclopramide, antipsychotics | Increased extrapyramidal effects |
| Antihypertensives / CCBs | Amlodipine, verapamil, ACE inhibitors | Enhanced hypotension |
| Anticholinergics | TCAs, oxybutynin | Additive anticholinergic toxicity |
| QT-prolonging drugs | Amiodarone, sotalol, certain antibiotics | Additive QT risk |
Bottom line: Cinnarizine's three mechanisms — H₁ blockade, calcium channel antagonism, and D2 blockade — drive a broad interaction profile. The most clinically important interactions are with CNS depressants, antiparkinsonian drugs, and antihypertensives. It should be used with caution in elderly patients and avoided in those with Parkinson's disease or on levodopa therapy.
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