Bupropion–Propranolol Drug Interaction
Bupropion is a CYP2D6 inhibitor that can increase exposure to drugs metabolized by CYP2D6. [1] Propranolol exposure can increase when coadministered with CYP2D6 inhibitors such as bupropion. [2]
Interaction Mechanism
Bupropion inhibits CYP2D6 activity. [1] Propranolol disposition involves CYP2D6 among other pathways. [2] Coadministration with CYP2D6 inhibitors can increase propranolol exposure. [2]
Clinical Significance
Increased propranolol exposure increases the likelihood of clinically relevant beta-blocker effects. [2] The most important safety concerns involve exaggerated pharmacodynamic effects such as bradycardia and hypotension, which warrant monitoring. [2]
Management Strategy
Propranolol and bupropion should be coadministered with caution due to increased propranolol exposure risk. [2] Dose reduction of propranolol should be considered when a CYP2D6 substrate is given with bupropion, particularly for drugs with a narrow therapeutic index. [1] Close monitoring for beta-blocker adverse effects should be performed after initiation, dose changes, and at steady state. [2]
Practical Monitoring
Heart rate should be monitored for bradycardia. [2] Blood pressure should be monitored for hypotension. [2] Symptoms of excessive beta blockade should be assessed clinically after starting or adjusting either medication. [2]
Alternative Approaches
If beta-blockade is still required and interaction risk is unacceptable, selection of an alternative agent for which CYP2D6 inhibition is less likely to increase exposure should be considered. [2]
Common Pitfalls to Avoid
Avoid assuming pharmacokinetic interaction is clinically irrelevant when propranolol is used with a known CYP2D6 inhibitor. [2] Avoid starting propranolol at the usual dose without subsequent monitoring when bupropion is present. [2]
Summary of Recommended Care
CYP2D6 inhibition by bupropion can increase propranolol exposure. [1] Coadministration should involve caution, consideration of propranolol dose adjustment, and monitoring for bradycardia and hypotension. [1] [2]