Metoprolol

Telaprevir Decrease AUC by 92% Systemic Hormonal Contraceptives Prevention or Management Advise patients to change to non-hormonal methods of birth control during rifampin therapy Estrogens Decrease exposure Progestins Anticonvulsants Phenytoin § Decrease exposure § Antiarrhythmics Disopyramide Decrease exposure Mexiletine Decrease exposure Quinidine Decrease exposure Propafenone Decrease AUC by 50% to 67% Tocainide Decrease exposure Antiestrogens Tamoxifen Decrease AUC by 86% Toremifene Decrease steady state concentrations of toremifene in serum Antithrombotic Agents Clopidogrel Prevention or Management Concomitant use of clopidogrel and rifampin should be discouraged Increase active metabolite exposure and risk of bleeding Ticagrelor Prevention or Management Avoid use Decrease exposure Antipsychotics Haloperidol Decrease plasma concentrations by 70% Lurasidone Prevention or Management: Concomitant use is contraindicated (See CONTRADICTIONS ) Decrease exposure Oral Anticoagulants Prevention or Management Perform prothrombin time daily or as frequently as necessary to establish and maintain the required dose of anticoagulant Warfarin Decrease exposure Antifungals Fluconazole Decrease AUC by 23% Itraconazole Prevention or Management Not recommended 2 weeks before and during itraconazole treatment Decrease exposure Ketoconazole Decrease exposure Beta-blockers Metoprolol Decrease exposure Propranolol Decrease exposure Benzodiazepines Diazepam *,¶ Decrease exposure Benzodiazepine-Related Drugs Zopiclone Decrease AUC by 82% Zolpidem Decrease AUC by 73% Calcium Channel Blockers ¶ Diltiazem Decrease exposure Nifedipine # Decrease exposure Verapamil Decrease exposure Corticosteroids Þ Prednisolone Decrease exposure Cardiac Glycosides Digoxin Prevention or Management Measure serum digoxin concentrations before initiating rifampin.

Increases bradycardia risk; beta-blockers may exacerbate rebound hypertension following clonidine withdrawal. Withdraw metoprolol several days before gradual clonidine withdrawal.

Concomitant use increases risk of bradycardia. Both agents slow atrioventricular conduction and decrease heart rate.

Concomitant use increases risk of bradycardia. Both agents slow atrioventricular conduction and decrease heart rate.

Patients may be unresponsive to usual doses of epinephrine used to treat allergic reactions while taking beta-blockers.

Strong CYP2D6 inhibitor that doubles metoprolol concentrations, decreasing cardioselectivity. Close monitoring required.

Possible significant hypertension may theoretically occur up to 14 days following discontinuation of concomitant administration with irreversible MAO inhibitors.

(7.2 ) CYP2D6 Inhibitors are likely to increase metoprolol concentration. ( 7.4 ) Beta-blockers including metoprolol, may exacerbate the rebound hypertension that can follow the withdrawal of clonidine. Observe patients treated with metoprolol plus a catecholamine depletor for evidence of hypotension or marked bradycardia, which may produce vertigo, syncope, or postural hypotension 7.2 Epinephrine While taking beta-blockers, patients with a history of severe anaphylactic reactions to a variety of allergens may be more reactive to repeated challenge and may be unresponsive to the usual doses of epinephrine used to treat an allergic reaction.

Catecholamine-depleting drugs with additive effect causing hypotension, marked bradycardia, vertigo, syncope, or postural hypotension.

Strong CYP2D6 inhibitor that doubles metoprolol concentrations, decreasing cardioselectivity. Close monitoring required.

Strong CYP2D6 inhibitor that doubles metoprolol concentrations, decreasing cardioselectivity. Close monitoring required.

Strong CYP2D6 inhibitor that doubles metoprolol concentrations, decreasing cardioselectivity. Close monitoring required.

Catecholamine-depleting drug with additive effect on metoprolol causing hypotension or marked bradycardia, potentially producing vertigo, syncope, or postural hypotension.

Concomitant use increases risk of bradycardia. Both agents slow atrioventricular conduction and decrease heart rate.

Beta-blocker with decreased clearance when given with verapamil, resulting in additive negative effects on heart rate and AV conduction.

Antihypertensive effect of alpha-adrenergic blocker may be potentiated by metoprolol.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

Bupropion inhibits CYP2D6 and can increase metoprolol concentrations; consider dose reduction of metoprolol.

CYP2D6 substrate beta-blocker. Bupropion inhibits CYP2D6, increasing metoprolol exposure. Dose reduction may be necessary.

CYP2D6 substrate beta-blocker. Bupropion inhibits CYP2D6 and can increase metoprolol concentrations. Consider dose reduction of metoprolol when used with bupropion.

Therefore, coadministration of bupropion with drugs that are metabolized by CYP2D6 isoenzyme including certain antidepressants (e.g., nortriptyline, imipramine, desipramine, paroxetine, fluoxetine, sertraline), antipsychotics (e.g., haloperidol, risperidone, thioridazine), beta-blockers (e.g., metoprolol), and Type 1C antiarrhythmics (e.g., propafenone, flecainide), should be approached with caution and should be initiated at the lower end of the dose range of the concomitant medication.

Concomitant use may produce additive reduction in myocardial contractility due to negative chronotropic and inotropic effects.

Antihypertensive effect of alpha-adrenergic agent may be potentiated by metoprolol.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

CYP2D6 substrate; cinacalcet is a strong CYP2D6 inhibitor. Dose adjustment may be required for concomitant CYP2D6-metabolized medications.

Cinacalcet is a strong CYP2D6 inhibitor. Dose adjustments may be required for concomitant CYP2D6 substrate medications.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

Desvenlafaxine increases metoprolol levels. Reduce dose by up to one-half with 400 mg desvenlafaxine; no adjustment needed with 100 mg or lower.

Desvenlafaxine increases metoprolol exposure. Reduce dose by up to one-half with 400 mg desvenlafaxine; no adjustment needed with 100 mg or lower.

Concomitant use increases exposure (Cmax and AUC). Reduce dose by up to one-half if co-administered with 400 mg desvenlafaxine.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

Beta-adrenergic blocking agent that antagonizes cardiac effects of dopamine.

Concomitant administration with metoprolol may enhance vasoconstrictive action of ergot alkaloids.

Beta blocker that increased metoprolol AUC and Cmax by approximately 31% and 38% respectively when co-administered with felodipine; well tolerated in clinical trials.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

Propranolol or Metoprolol: Reduce dose if coadministered with fluvoxamine and titrate more cautiously ( 7.3 ) . One case of bradycardia and hypotension and a second case of orthostatic hypotension have been reported with the coadministration of immediate-release fluvoxamine maleate tablets and metoprolol. If propranolol or metoprolol is coadministered with fluvoxamine maleate extended-release capsules, a reduction in the initial beta-blocker dose and more cautious dose titration are recommended.

Antihypertensive effect of alpha-adrenergic blocker may be potentiated by metoprolol.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

May inhibit presystemic metabolism of metoprolol, leading to increased concentrations of metoprolol.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

Antihypertensive; small reductions in blood pressure occur following coadministration with tadalafil.

Observe patients treated with metoprolol succinate extended-release tablets plus a catecholamine depletor for evidence of hypotension or marked bradycardia, which may produce vertigo, syncope, or postural hypotension. 7.2 CYP2D6 Inhibitors Drugs that are strong inhibitors of CYP2D6 such as quinidine, fluoxetine, paroxetine, and propafenone were shown to double metoprolol concentrations. While there is no information about moderate or weak inhibitors, these too are likely to increase metoprolol concentration.

( 7.1 ) CYP2D6 inhibitors: Increased metoprolol concentration. ( 7.2 ) 7.1 Drug Interactions with Metoprolol Catecholamine Depleting Drugs: The concomitant use of catecholamine-depleting drugs (e.g., reserpine, monoamine oxidase (MAO) inhibitors) with beta adrenergic blockers may have an additive affect and increase the risk of hypotension or bradycardia CYP2D6 Inhibitors: Drugs that are strong inhibitors of CYP2D6 such as quinidine, fluoxetine, paroxetine, and propafenone were shown to double metoprolol concentrations. While there is no information about moderate or weak inhibitors, these too are likely to increase metoprolol concentration.

Bupropion inhibits CYP2D6, increasing metoprolol AUC and Cmax approximately 4- and 2-fold respectively. Consider dose reduction when using with CONTRAVE.

Paroxetine inhibits CYP2D6, increasing exposure of metoprolol. Dosage reduction may be needed.

Beta-adrenergic blockers may potentiate postural hypotensive effect of first dose of prazosin, probably by preventing reflex tachycardia.

β-Blockers: metoprolol, timolol ↑ beta-blockers Caution is warranted and clinical monitoring of patients is recommended.

β-Blockers: metoprolol, timolol ↑ beta-blockers Caution is warranted and clinical monitoring of patients is recommended.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

Sevelamer Drug Interactions Oral drugs for which sevelamer did not alter the pharmacokinetics when administered concomitantly Digoxin Enalapril Iron Metoprolol Warfarin Oral drugs that have demonstrated interaction with sevelamer and are to be dosed separately from sevelamer carbonate Ciprofloxacin Mycophenolate mofetil Dosing Recommendations Take at least 2 hours before or 6 hours after sevelamer Take at least 2 hours before sevelamer • For oral medication where a reduction in the bioavailability of that medication would have a clinically significant effect on its safety or efficacy consider separation of the timing of administration and/or monitor clinical responses or blood levels of the concomitant medication. ( 7 ) • Sevelamer did not alter the pharmacokinetics of digoxin, enalapril, iron, metoprolol and warfarin.

Sevelamer Drug Interactions Oral drugs for which sevelamer did not alter the pharmacokinetics when administered concomitantly Digoxin Enalapril Iron Metoprolol Warfarin Oral drugs that have demonstrated interaction with sevelamer and are to be dosed separately from sevelamer carbonate Ciprofloxacin Mycophenolate mofetil Dosing Recommendations Take at least 2 hours before or 6 hours after sevelamer Take at least 2 hours before sevelamer • For oral medication where a reduction in the bioavailability of that medication would have a clinically significant effect on its safety or efficacy consider separation of the timing of administration and/or monitor clinical responses or blood levels of the concomitant medication. ( 7 ) • Sevelamer did not alter the pharmacokinetics of digoxin, enalapril, iron, metoprolol and warfarin.

Table 4: Sevelamer Drug Interactions Oral drugs for which sevelamer did not alter the pharmacokinetics when administered concomitantly Digoxin Enalapril Iron Metoprolol Warfarin Oral drugs that have demonstrated interaction with sevelamer and are to be dosed separately from sevelamer hydrochloride Dosing Recommendations Ciprofloxacin Mycophenolate mofetil Take at least 2 hours before or 6 hours after sevelamer Take at least 2 hours before sevelamer • When clinically significant drug interactions are expected, separate the timing of administration and monitor clinical responses or blood levels of the concomitant medication. ( 7 ) • Sevelamer did not alter the pharmacokinetics of digoxin, enalapril, iron, metoprolol, and warfarin.

Small reductions in blood pressure occurred following coadministration of tadalafil compared with placebo.

Beta-adrenergic receptor antagonist that may reduce melatonin production and decrease the efficacy of tasimelteon when administered at nighttime.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

Potent CYP2D6 inhibitor may increase plasma concentration of metoprolol, decreasing cardioselectivity.

( 7.7 ) Metoprolol: Possibly reduced blood-pressure lowering effect despite increased metoprolol plasma levels. Caution should be exercised with co-administration of venlafaxine and metoprolol. Metoprolol Concomitant administration of venlafaxine (50 mg every 8 hours for 5 days) and metoprolol (100 mg every 24 hours for 5 days) to 18 healthy male subjects in a pharmacokinetic interaction study for both drugs resulted in an increase of plasma concentrations of metoprolol by approximately 30% to 40% without altering the plasma concentrations of its active metabolite, α-hydroxymetoprolol.

( 7.7 ) Metoprolol: Possibly reduced blood pressure lowering effect despite increased metoprolol plasma levels. Caution should be exercised with co-administration of venlafaxine and metoprolol. Metoprolol - Concomitant administration of venlafaxine (50 mg every 8 hours for 5 days) and metoprolol (100 mg every 24 hours for 5 days) to 18 healthy male subjects in a pharmacokinetic interaction study for both drugs resulted in an increase of plasma concentrations of metoprolol by approximately 30-40% without altering the plasma concentrations of its active metabolite, α‑hydroxymetoprolol.

( 7.7 ) Metoprolol: Possibly reduced blood pressure lowering effect despite increased metoprolol plasma levels. Caution should be exercised with co-administration of venlafaxine and metoprolol. Metoprolol - Concomitant administration of venlafaxine (50 mg every 8 hours for 5 days) and metoprolol (100 mg every 24 hours for 5 days) to 18 healthy male subjects in a pharmacokinetic interaction study for both drugs resulted in an increase of plasma concentrations of metoprolol by approximately 30-40% without altering the plasma concentrations of its active metabolite, α‑hydroxymetoprolol.

albuterol, systemic and inhaled amoxicillin ampicillin, with or without sulbactam atenolol azithromycin caffeine, dietary ingestion cefaclor co-trimoxazole (trimethoprim and sulfamethoxazole) diltiazem dirithromycin enflurane famotidine felodipine finasteride hydrocortisone isoflurane isoniazid isradipine influenza vaccine ketoconazole lomefloxacin mebendazole medroxyprogesterone methylprednisolone metronidazole metoprolol nadolol nifedipine nizatidine norfloxacin ofloxacin omeprazole prednisone, prednisolone ranitidine rifabutin roxithromycin sorbitol (purgative doses do not inhibit theophylline absorption) sucralfate terbutaline, systemic terfenadine tetracycline tocainide The Effect of Other Drugs on Theophylline Serum Concentration Measurements: Most serum theophylline assays in clinical use are immunoassays which are specific for theophylline.

Beta-Blockers: (e.g., metoprolol, carvedilol, timolol) ↔ atazanavir ↑ beta-blockers Clinical monitoring is recommended when beta-blockers that are metabolized by CYP2D6 are coadministered with EVOTAZ.

Examples: Metoprolol, propranolol Hypoglycemic Agents Clinical Impact: Aspirin may increase the serum glucose-lowering action of insulin and sulfonylureas leading to hypoglycemia.

Metoprolol Administration of 40 mg/day citalopram for 22 days resulted in a two-fold increase in the plasma levels of the beta-adrenergic blocker metoprolol. Increased metoprolol plasma levels have been associated with decreased cardioselectivity. Coadministration of citalopram and metoprolol had no clinically significant effects on blood pressure or heart rate.

Metoprolol - Administration of 40 mg/day citalopram for 22 days resulted in a two-fold increase in the plasma levels of the betaadrenergic blocker metoprolol. Increased metoprolol plasma levels have been associated with decreased cardioselectivity. Coadministration of citalopram and metoprolol had no clinically significant effects on blood pressure or heart rate.

Beta-Blockers: e.g., metoprolol carvedilol timolol ↑ beta-blockers Clinical monitoring is recommended for coadministration with beta-blockers that are metabolized by CYP2D6.

carvedilol, metoprolol, timolol ↑ beta-blockers Clinical monitoring of patients is recommended.

carvedilol, metoprolol, timolol ↑ beta-blockers Clinical monitoring of patients is recommended.

carvedilol, metoprolol, timolol ↑ beta-blockers Clinical monitoring is recommended for co-administration with beta-blockers that are metabolized by CYP2D6.

β-Blockers: e.g., carvedilol, metoprolol, timolol ↑ beta-blockers Clinical monitoring is recommended for co-administration with beta-blockers that are metabolized by CYP2D6.

Drug interaction mentioned but description incomplete in provided text.

Beta-Blockers and Other CYP2D6 Substrates Dronedarone increased the exposure of propranolol and metoprolol.

Beta-Blockers: e.g., metoprolol timolol ↑ beta-blockers Clinical monitoring is recommended and a dosage decrease of the beta blocker may be necessary when these agents are coadministered with GENVOYA.

Beta-Blockers: e.g., metoprolol timolol ↑ beta-blockers Clinical monitoring is recommended and a dose decrease of the beta-blocker may be necessary when these agents are coadministered with STRIBILD.

7.20 Metoprolol Administration of 20 mg/day escitalopram oxalate for 21 days in healthy volunteers resulted in a 50% increase in C max and 82% increase in AUC of the beta-adrenergic blocker metoprolol (given in a single dose of 100 mg). Increased metoprolol plasma levels have been associated with decreased cardioselectivity. Coadministration of escitalopram oxalate and metoprolol had no clinically significant effects on blood pressure or heart rate.

7.20 Metoprolol Administration of 20 mg/day escitalopram oxalate for 21 days in healthy volunteers resulted in a 50% increase in C max and 82% increase in AUC of the beta-adrenergic blocker metoprolol (given in a single dose of 100 mg). Increased metoprolol plasma levels have been associated with decreased cardioselectivity. Coadministration of escitalopram oxalate and metoprolol had no clinically significant effects on blood pressure or heart rate.

7 DRUG INTERACTIONS Table 2: Oral drugs that can be administered concomitantly with ferric citrate Amlodipine Aspirin Atorvastatin Calcitriol Clopidogrel Digoxin Diltiazem Doxercalciferol Enalapril Fluvastatin Glimepiride Levofloxacin Losartan Metoprolol Pravastatin Propranolol Sitagliptin Warfarin Oral drugs that have to be separated from ferric citrate and meals Dosing Recommendations Doxycycline Take at least 1 hour before ferric citrate Ciprofloxacin Take at least 2 hours before or after ferric citrate Oral medications not listed in Table 2.

Interactions with Drugs Metabolized by CYP2D6 Imatinib mesylate tablets increased the mean C max and AUC of metoprolol by approximately 23% suggesting that imatinib mesylate tablets have a weak inhibitory effect on CYP2D6-mediated metabolism.

Concurrent administration of any of the following drugs with lorazepam had no effect on the pharmacokinetics of lorazepam: metoprolol, cimetidine, ranitidine, disulfiram, propranolol, metronidazole, and propoxyphene.

(7.1) • CYP2D6 Inhibitors are likely to increase metoprolol concentration. (7.2) • Beta-blockers including metoprolol, may exacerbate the rebound hypertension that can follow the withdrawal of clonidine. Observe patients treated with metoprolol succinate extended-release plus a catecholamine depletor for evidence of hypotension or marked bradycardia, which may produce vertigo, syncope, or postural hypotension.

( 7.1 ) • CYP2D6 Inhibitors are likely to increase metoprolol concentration. ( 7.2 ) • Beta-blockers including metoprolol, may exacerbate the rebound hypertension that can follow the withdrawal of clonidine. Observe patients treated with metoprolol succinate extended-release tablets plus a catecholamine depletor for evidence of hypotension or marked bradycardia, which may produce vertigo, syncope, or postural hypotension.

Examples propafenone, flecainide, atomoxetine, desipramine, dextromethorphan, metoprolol, nebivolol, perphenazine, tolterodine, venlafaxine, risperidone.

Table 3: No observed clinically important drug interactions of Veltassa Angiotensin-converting enzyme (ACE) inhibitors Benazepril, captopril, enalapril, fosinopril, lisinopril, perindopril, quinapril, ramipril, trandolapril Angiotensin II receptor blockers (ARB) Azilsartan, candesartan, irbesartan, losartan, olmesartan, valsartan β-adrenoceptor blockers (β-blocker) Metoprolol Loop diuretics Furosemide, bumetanide, torasemide Mineralocorticoid receptor antagonists (MRA) Eplerenone, finerenone, spironolactone Neprilysin inhibitors Sacubitril Sodium-glucose cotransporter-2 (SGLT-2) inhibitors Canagliflozin, dapagliflozin, empagliflozin Antibiotics Trimethoprim, amoxicillin, cephalexin Anticoagulants Warfarin, apixaban, rivaroxaban Anti-parathyroid agents and Thyroid preparations Cinacalcet Antithrombotic agents Clopidogrel, acetylsalicylic acid Blood glucose lowering drugs Glipizide Calcium channel blockers Amlodipine, verapamil Immunosuppressants Tacrolimus Others Lithium, allopurinol, atorvastatin, digoxin, phenytoin, riboflavin, sevelamer

In 4 patients, administration of metoprolol with propafenone increased the metoprolol plasma concentrations at steady state by 100% to 400%. The pharmacokinetics of propafenone was not affected by the coadministration of either propranolol or metoprolol.

Non-interactions of quinidine with other drugs: Quinidine has no clinically significant effect on the pharmacokinetics of diltiazem, flecainide, mephenytoin, metoprolol, propafenone, propranolol, quinine, timolol, or tocainide .

Non-Interactions of Quinidine With Other Drugs Quinidine has no clinically significant effect on the pharmacokinetics of diltiazem, flecainide, mephenytoin, metoprolol, propafenone, propranolol, quinine, timolol , or tocainide .

Although clinical drug interaction studies have not been performed, antimalarial doses (greater than or equal to 600 mg) of quinine may inhibit the metabolism of other drugs that are CYP2D6 substrates (e.g., flecainide, debrisoquine, dextromethorphan, metoprolol, paroxetine ).

Nadolol/Metoprolol : In a drug interactions study, effects of multiple doses of nadolol 80 mg or metoprolol 100 mg every 12 hours on the pharmacokinetics of a single dose of 10 mg rizatriptan were evaluated in healthy subjects (n=12).

Examples: propafenone, flecainide, atomoxetine, desipramine, dextromethorphan, metoprolol, nebivolol, perphenazine, thioridazine, tolterodine, venlafaxine Phenytoin Clinical Impact: Phenytoin is a narrow therapeutic index drug.

7 DRUG INTERACTIONS Table 1 Oral drugs that can be administered concomitantly with Velphoro Calcitriol Ciprofloxacin Digoxin Enalapril Furosemide HMG-CoA reductase inhibitors Hydrochlorothiazide Losartan Metoprolol Nifedipine Omeprazole Quinidine Warfarin Oral drugs that are to be separated from Velphoro Dosing Recommendations Doxycycline Acetylsalicylic acid Cephalexin Take at least 1 hour before Velphoro. Velphoro can be administered concomitantly with oral calcitriol, ciprofloxacin, digoxin, enalapril, furosemide, HMG‑CoA reductase inhibitors, hydrochlorothiazide, losartan, metoprolol, nifedipine, omeprazole, quinidine and warfarin.

Drugs that have been documented not to interact with theophylline or drugs that produce no clinically significant interaction with theophylline.* albuterol, systemic and inhaled mebendazole amoxicillin medroxyprogesterone ampicillin, with or without methylprednisolone sulbactam metronidazole atenolol metoprolol azithromycin nadolol caffeine, dietary ingestion nifedipine cefaclor nizatidine co-trimoxazole (trimethoprim and sulfamethoxazole) norfloxacin ofloxacin diltiazem omeprazole dirithromycin prednisone, prednisolone enflurane ranitidine famotidine rifabutin felodipine roxithromycin finasteride Sorbitol (purgative doses do not inhibit hydrocortisone theophylline absorption) isoflurane sucralfate isoniazid terbutaline, systemic isradipine terfenadine influenza vaccine tetracycline ketoconazole tocainide lomefloxacin * Refer to PRECAUTIONS, Drug Interactions for information regarding table.

albuterol, systemic and inhaled mebendazole amoxicillin medroxyprogesterone ampicillin, with or without sulbactam methylprednisolone atenolol metronidazole azithromycin metoprolol caffeine, dietary ingestion nadolol cefaclor nifedipine co-trimoxazole (trimethoprim and sulfamethoxazole) nizatidine diltiazem norfloxacin dirithromycin ofloxacin enflurane omeprazole famotidine prednisone, prednisolone felodipine ranitidine finasteride rifabutin hydrocortisone roxithromycin isoflurane Sorbitol (purgative doses do not inhibit theophylline absorption) isoniazid sucralfate isradipine terbutaline, systemic influenza vaccine terfenadine ketoconazole tetracycline lomefloxacin tocainide

Drug interaction studies have indicated that the maximum concentrations of metoprolol and propanolol are increased after the administration of verapamil.