DRUG INTERACTIONS
Pharmacokinetic Drug-Drug Interactions
Impact of Propranolol on Other Drugs
Warfarin: Warfarin concentrations are increased when administered with propranolol. Monitor prothrombin time accordingly [see Clinical Pharmacology (
12.7
)].
Propafenone: Co-administration of propranolol increases the plasma concentrations of propafenone. Monitor patients for symptoms of excessive exposure to propafenone including bradycardia and postural hypotension [see Clinical Pharmacology (
12.7
)].
Impact of Other Drugs on Propranolol
CYP2D6-, CYP1A2- and CYP2C19 Inhibitors: CYP2D6 inhibitors (e.g. bupropion, fluoxetine, paroxetine, quinidine), CYP1A2 inhibitors (e.g., ciprofloxacin, enoxamine, fluvoxamine) and CYP2C19 inhibitors (e.g., fluconazole, fluvoxamine, ticlopidine) increase exposure to propranolol when co-administered with INNOPRAN XL. Monitor patients for bradycardia and hypotension [see Clinical Pharmacology (
12.7
)].
CYP1A2 and CYP2C19 Inducers: CYP1A2 inducers (e.g., phenytoin, montelukast, smoking) and CYP2C19 inducers (e.g. rifampin) decrease the plasma levels of propranolol resulting in a loss of efficacy [see Clinical Pharmacology (
12.7
)].
Cholestyramine and Colestipol: Co-administered cholestyramine or colestipol significantly reduces the plasma concentrations of co-administered propranolol which may result in loss of efficacy [see Clinical Pharmacology (
12.7
)].
Pharmacodynamic Drug-Drug Interactions
Adrenergic Agonists: Beta-blockers may antagonize the antihypertensive effects of clonidine, and rebound hypertension may result if clonidine is withdrawn abruptly. If clonidine and a beta-blocker are co-administered, withdraw the beta-blocker several days before the withdrawal of clonidine
Alpha Blockers: Co-administration of beta-blockers with alpha blocker (e.g., prazosin) has been associated with prolongation of first dose hypotension and syncope.
Dobutamine: Propranolol may reduce sensitivity to dobutamine stress echocardiography in patients undergoing evaluation for myocardial ischemia.
Antidepressants: The hypotensive effect of MAO inhibitors or tricyclic antidepressants may be exacerbated when administered with beta-blockers. Monitor patients for postural hypotension.
Nonsteroidal Anti-Inflammatory Drugs:
Nonsteroidal anti-inflammatory drugs (NSAIDS) may attenuate the antihypertensive effect of beta-adrenoreceptor blocking agents. Monitor blood pressure.
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