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Interactions between sympathomimetic amines and antidepressant agents in man
British Medical Journal
|February 10, 1973
Summary
Monoamine oxidase inhibitors potentiate phenylephrine but not other vasoactive drugs. Tricyclic antidepressants like imipramine significantly potentiate phenylephrine, noradrenaline, and adrenaline, increasing cardiovascular risks.
Area of Science:
- Pharmacology
- Cardiovascular Physiology
Background:
- Drug interactions between antidepressants and sympathomimetic agents are a clinical concern.
- Understanding these interactions is crucial for patient safety, especially in dental and respiratory medicine.
Purpose of the Study:
- To investigate the cardiovascular effects of sympathomimetic drugs after administration of monoamine oxidase inhibitors (MAOIs) or tricyclic antidepressants (TCAs).
- To assess the potential for drug interactions with phenylephrine, noradrenaline, adrenaline, and isoprenaline.
Main Methods:
- Healthy volunteers received intravenous infusions of phenylephrine, noradrenaline, adrenaline, and isoprenaline.
- Cardiovascular responses were measured after 5-7 days of treatment with phenelzine, tranylcypromine (MAOIs), or imipramine (TCA).
- Responses were compared to control conditions.
Main Results:
- MAOIs potentiated phenylephrine's pressor effect (2-2.5 fold) but not other agents.
- Imipramine potentiated phenylephrine (2-3 fold), noradrenaline (4-8 fold), and adrenaline (2-4 fold).
- Adrenaline infusions during imipramine treatment caused dysrhythmias; isoprenaline showed no significant changes.
Conclusions:
- MAOIs are unlikely to cause significant potentiation of sympathomimetic agents used in dentistry.
- TCAs may cause hazardous potentiation of cardiovascular effects with noradrenaline and adrenaline.
- Isoprenaline inhalation risks are not increased by concurrent MAOI or TCA therapy in asthmatics.
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