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Drug Interactions between Lopressor and Tambocor

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

metoprolol flecainide

Applies to: Lopressor (metoprolol) and Tambocor (flecainide)

MONITOR: Beta-blockers and flecainide may have additive negative inotropic effects. Areas under the curve were increased for both drugs and negative inotropic effects occurred when flecainide and propranolol were given to normal subjects. A case of bradycardia, atrioventricular block and cardiac arrest has been reported after sotalol was added to flecainide; however, causality was not definitely determined.

MANAGEMENT: Careful monitoring of the patient's hemodynamic status is recommended during concomitant administration. The same precaution should be observed when beta blocker ophthalmic solutions are used, since they are systemically absorbed and can produce clinically significant systemic effects even at low or undetectable plasma levels. Patients should be advised to promptly report symptoms such as dizziness, slow or irregular heartbeats, syncope, or palpitations.

References

  1. Warren R, Vohra J, Hunt D, Hamer A "Serious interactions of sotalol with amiodarone and flecainide." Med J Aust 152 (1990): 277
  2. Holtzman JL, Kvam DC, Berry DA, et al. "The pharmacodynamic and pharmacokinetic interaction of flecainide acetate with propranolol: effects on cardiac function and drug clearance." Eur J Clin Pharmacol 33 (1987): 97-9
  3. Lewis GP, Holtzman JL "Interaction of flecainide with digoxin and propranolol." Am J Cardiol 53 (1984): b52-7
  4. Myerburg RJ, Kessler KM, Cox MM, et al. "Reversal of proarrhythmic effects of flecainide acetate and encainide hydrochloride by propranolol." Circulation 80 (1989): 1571-9
  5. Minish T, Herd A "Symptomatic bradycardia secondary to interaction between topical timolol maleate, verapamil, and flecainide: a case report." J Emerg Med 22 (2002): 247-9
View all 5 references

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Drug and food interactions

Moderate

metoprolol food

Applies to: Lopressor (metoprolol)

ADJUST DOSING INTERVAL: The bioavailability of metoprolol may be enhanced by food.

MANAGEMENT: Patients may be instructed to take metoprolol at the same time each day, preferably with or immediately following meals.

References

  1. "Product Information. Lopressor (metoprolol)." Novartis Pharmaceuticals PROD (2001):
  2. Darcy PF "Nutrient-drug interactions." Adverse Drug React Toxicol Rev 14 (1995): 233-54

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Moderate

metoprolol food

Applies to: Lopressor (metoprolol)

ADJUST DOSING INTERVAL: Concurrent administration with calcium salts may decrease the oral bioavailability of atenolol and possibly other beta-blockers. The exact mechanism of interaction is unknown. In six healthy subjects, calcium 500 mg (as lactate, carbonate, and gluconate) reduced the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of atenolol (100 mg) by 51% and 32%, respectively. The elimination half-life increased by 44%. Twelve hours after the combination, beta-blocking activity (as indicated by inhibition of exercise tachycardia) was reduced compared to that with atenolol alone. However, during a 4-week treatment in six hypertensive patients, there was no difference in blood pressure values between treatments. The investigators suggest that prolongation of the elimination half-life induced by calcium coadministration may have led to atenolol cumulation during long-term dosing, which compensated for the reduced bioavailability.

MANAGEMENT: It may help to separate the administration times of beta-blockers and calcium products by at least 2 hours. Patients should be monitored for potentially diminished beta-blocking effects following the addition of calcium therapy.

References

  1. Kirch W, Schafer-Korting M, Axthelm T, Kohler H, Mutschler E "Interaction of atenolol with furosemide and calcium and aluminum salts." Clin Pharmacol Ther 30 (1981): 429-35

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Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

See also

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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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