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Label Changes for:

Lopressor (Metoprolol Tartrate) Tablets and Injection

December 2012

Changes have been made to the PRECAUTIONS sections of the safety label.

Detailed View: Safety Labeling Changes Approved By FDA Center for Drug Evaluation and Research (CDER) 


December 2012



  • Start at a low dose and uptitrate slowly…
Drug Interactions
  • Catecholamine-depleting drugs….
CYP2D6 Inhibitors:
  • …..Increase in  plasma concentrations of Metoprolol would decrease the cardioselectivity of Metoprolol…
  • Hydralazine: Concomitant administration of hydralazine may inhibit presystemic metabolism of metoprolol leading to increased concentrations of metoprolol.
  • Alpha-adrenergic agents: Antihypertensive effect of alpha-adrenergic blockers such as guanethidine, betanidine, reserpine, alpha-methyldopa or clonidine may be potentiated by betablockers including Lopressor…
  • Ergot alkaloid: Concomitant administration with beta-blockers may enhance the vasoconstrictive action of ergot alkaloids.
  • Dipyridamole: In general, administration of a beta-blocker should be withheld before dipyridamole testing, with careful monitoring of heart rate following the dipyridamole injection.
Carcinogenesis, Mutagenesis, Impairment of Fertility
  • Reproduction toxicity studies in mice, rats and rabbits did not indicate teratogenic potential for metoprolol tartrate…
Pregnancy Category C
  • Upon confirming the diagnosis of pregnancy, women should immediately inform the doctor…
  • The effects of Lopressor on the fertility of human have not been studied…