toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Both drugs can cause metabolic acidosis.diclofenacMonitor Closely (1)diclofenac increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.diethylpropionMonitor Closely (2)formoterol and diethylpropion both decrease sedation. Use Caution/Monitor. formoterol and diethylpropion both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.difenoxin hclMonitor Closely (1)difenoxin hcl increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diflunisalMonitor Closely (1)diflunisal increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.digoxinMonitor Closely (1)digoxin increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.dimenhydrinateMonitor Closely (1)dimenhydrinate increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diphenhydramineMonitor Closely (1)diphenhydramine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diphenoxylate hclMonitor Closely (1)diphenoxylate hcl increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dipipanoneMonitor Closely (1)dipipanone increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.disopyramideSerious - Use Alternative (1)disopyramide and formoterol both increase QTc interval. Avoid or Use Alternate Drug.dobutamineMonitor Closely (3)dobutamine and formoterol both decrease serum potassium. Use Caution/Monitor. dobutamine and formoterol both decrease sedation. Use Caution/Monitor. dobutamine and formoterol both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dofetilideSerious - Use Alternative (1)dofetilide and formoterol both increase QTc interval. Avoid or Use Alternate Drug.dolasetronMonitor Closely (1)dolasetron and formoterol both increase QTc interval. Modify Therapy/Monitor Closely.donepezilMonitor Closely (1)donepezil and formoterol both increase QTc interval. Use Caution/Monitor.dopamineMonitor Closely (2)formoterol and dopamine both decrease sedation. Use Caution/Monitor. formoterol and dopamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dopexamineMonitor Closely (4)dopexamine, formoterol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. dopexamine and formoterol both decrease serum potassium. Use Caution/Monitor. dopexamine and formoterol both decrease sedation. Use Caution/Monitor. dopexamine and formoterol both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.doxepinMonitor Closely (1)doxepin increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (2)doxepin and formoterol both increase QTc interval. Avoid or Use Alternate Drug. doxepin, formoterol. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.dronedaroneSerious - Use Alternative (1)dronedarone and formoterol both increase QTc interval. Avoid or Use Alternate Drug.droperidolMonitor Closely (1)droperidol increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)droperidol and formoterol both increase QTc interval. Avoid or Use Alternate Drug.drospirenoneMonitor Closely (1)drospirenone increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.efavirenzMonitor Closely (1)efavirenz and formoterol both increase QTc interval. Use Caution/Monitor.encorafenibMonitor Closely (1)encorafenib and formoterol both increase QTc interval. Use Caution/Monitor.entrectinibSerious - Use Alternative (1)formoterol and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.ephedrineMonitor Closely (3)ephedrine and formoterol both decrease serum potassium. Use Caution/Monitor. ephedrine and formoterol both decrease sedation. Use Caution/Monitor. ephedrine and formoterol both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.epinephrineMonitor Closely (3)epinephrine and formoterol both decrease serum potassium. Use Caution/Monitor. epinephrine and formoterol both decrease sedation. Use Caution/Monitor. epinephrine and formoterol both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.Serious - Use Alternative (1)epinephrine and formoterol both increase QTc interval. Avoid or Use Alternate Drug.epinephrine racemicMonitor Closely (3)formoterol and epinephrine racemic both decrease serum potassium. Use Caution/Monitor. formoterol and epinephrine racemic both decrease sedation. Use Caution/Monitor. formoterol and epinephrine racemic both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.Serious - Use Alternative (1)epinephrine racemic and formoterol both increase QTc interval. Avoid or Use Alternate Drug.eribulinMonitor Closely (1)eribulin and formoterol both increase QTc interval. Use Caution/Monitor.erythromycin baseSerious - Use Alternative (1)erythromycin base and formoterol both increase QTc interval. Avoid or Use Alternate Drug.erythromycin ethylsuccinateSerious - Use Alternative (1)erythromycin ethylsuccinate and formoterol both increase QTc interval. Avoid or Use Alternate Drug.erythromycin lactobionateSerious - Use Alternative (1)erythromycin lactobionate and formoterol both increase QTc interval. Avoid or Use Alternate Drug.erythromycin stearateSerious - Use Alternative (1)erythromycin stearate and formoterol both increase QTc interval. Avoid or Use Alternate Drug.escitalopramMonitor Closely (1)escitalopram increases toxicity of formoterol by QTc interval. Use Caution/Monitor.esmololMonitor Closely (2)esmolol decreases effects of formoterol by pharmacodynamic antagonism. Use Caution/Monitor. esmolol increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.estazolamMonitor Closely (1)estazolam increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.ethacrynic acidMonitor Closely (1)formoterol and ethacrynic acid both decrease serum potassium. Use Caution/Monitor.Minor (1)formoterol, ethacrynic acid. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.ethanolMonitor Closely (1)ethanol increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.etodolacMonitor Closely (1)etodolac increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.eucalyptusMinor (1)eucalyptus increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.fenfluramineMonitor Closely (2)formoterol and fenfluramine both decrease sedation. Use Caution/Monitor. formoterol and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.fenoprofenMonitor Closely (1)fenoprofen increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.fexinidazoleSerious - Use Alternative (1)fexinidazole and formoterol both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.fingolimodMonitor Closely (1)fingolimod and formoterol both increase QTc interval. Use Caution/Monitor.flecainideMonitor Closely (1)flecainide and formoterol both increase QTc interval. Modify Therapy/Monitor Closely.fluconazoleSerious - Use Alternative (1)fluconazole and formoterol both increase QTc interval. Avoid or Use Alternate Drug.fluoxetineMonitor Closely (1)fluoxetine and formoterol both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular systemfluphenazineMonitor Closely (1)fluphenazine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and formoterol both increase QTc interval. Avoid or Use Alternate Drug.flurazepamMonitor Closely (1)flurazepam increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.flurbiprofenMonitor Closely (1)flurbiprofen increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.fluvoxamineMonitor Closely (1)fluvoxamine and formoterol both increase QTc interval. Modify Therapy/Monitor Closely.foscarnetMonitor Closely (1)formoterol and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.fostemsavirMonitor Closely (1)formoterol and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir. furosemideMonitor Closely (1)formoterol and furosemide both decrease serum potassium. Use Caution/Monitor.Minor (1)formoterol, furosemide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.gemifloxacinMonitor Closely (1)gemifloxacin and formoterol both increase QTc interval. Use Caution/Monitor.gentamicinMonitor Closely (1)formoterol and gentamicin both decrease serum potassium. Use Caution/Monitor.gilteritinibMonitor Closely (1)gilteritinib and formoterol both increase QTc interval. Use Caution/Monitor.glasdegibSerious - Use Alternative (1)formoterol and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation.goserelinMonitor Closely (1)goserelin increases toxicity of formoterol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.green teaMinor (1)green tea increases effects of formoterol by pharmacodynamic synergism. Minor/Significance Unknown. Due to caffeine content. Combination may increase CNS stimulatory effects due to caffeine in green tea.haloperidolMonitor Closely (1)haloperidol increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)formoterol and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.histrelinMonitor Closely (1)histrelin increases toxicity of formoterol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.hydrochlorothiazideMonitor Closely (1)formoterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)formoterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.hydromorphoneMonitor Closely (1)hydromorphone increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.hydroxychloroquine sulfateSerious - Use Alternative (1)hydroxychloroquine sulfate and formoterol both increase QTc interval. Avoid or Use Alternate Drug.hydroxyzineMonitor Closely (1)hydroxyzine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.ibuprofenMonitor Closely (1)ibuprofen increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.ibuprofen IVMonitor Closely (1)ibuprofen IV increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.ibutilideSerious - Use Alternative (1)formoterol and ibutilide both increase QTc interval. Avoid or Use Alternate Drug.iloperidoneMonitor Closely (2)formoterol and iloperidone both increase QTc interval. Modify Therapy/Monitor Closely. iloperidone increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.imipramineMonitor Closely (1)imipramine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (2)imipramine and formoterol both increase QTc interval. Avoid or Use Alternate Drug. imipramine, formoterol. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.indapamideMonitor Closely (1)formoterol and indapamide both decrease serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)formoterol and indapamide both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)formoterol, indapamide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.indomethacinMonitor Closely (1)indomethacin increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.inotuzumabSerious - Use Alternative (1)inotuzumab and formoterol both increase QTc interval. Avoid or Use Alternate Drug. If unable to avoid concomitant use, obtain ECGs and electrolytes before and after initiation of any drug known to prolong QTc, and periodically monitor as clinically indicated during treatment.isocarboxazidSerious - Use Alternative (1)isocarboxazid increases effects of formoterol by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.isoproterenolMonitor Closely (3)formoterol and isoproterenol both decrease serum potassium. Use Caution/Monitor. formoterol and isoproterenol both decrease sedation. Use Caution/Monitor. formoterol and isoproterenol both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.itraconazoleMonitor Closely (1)itraconazole and formoterol both increase QTc interval. Use Caution/Monitor.ivosidenibSerious - Use Alternative (1)ivosidenib and formoterol both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of QTc prolonging drugs with ivosidenib or replace with alternate therapies. If coadministration of a QTc prolonging drug is unavoidable, monitor for increased risk of QTc interval prolongation.ketoconazoleSerious - Use Alternative (1)formoterol and ketoconazole both increase QTc interval. Avoid or Use Alternate Drug.ketoprofenMonitor Closely (1)ketoprofen increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.ketorolacMonitor Closely (1)ketorolac increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.ketorolac intranasalMonitor Closely (1)ketorolac intranasal increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .ketotifen, ophthalmicMonitor Closely (1)ketotifen, ophthalmic increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.labetalolMonitor Closely (2)labetalol decreases effects of formoterol by pharmacodynamic antagonism. Use Caution/Monitor. labetalol increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.lapatinibMonitor Closely (1)formoterol and lapatinib both increase QTc interval. Modify Therapy/Monitor Closely.lefamulinSerious - Use Alternative (1)lefamulin and formoterol both increase QTc interval. Avoid or Use Alternate Drug.lenvatinibMonitor Closely (1)formoterol and lenvatinib both increase QTc interval. Use Caution/Monitor. Lenvatinib prescribing information recommends monitoring ECG closely when coadministered with QT prolonging drugs.leuprolideMonitor Closely (1)leuprolide increases toxicity of formoterol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.levalbuterolMonitor Closely (3)formoterol and levalbuterol both decrease serum potassium. Use Caution/Monitor. formoterol and levalbuterol both decrease sedation. Use Caution/Monitor. formoterol and levalbuterol both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.levofloxacinMonitor Closely (1)formoterol and levofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.levoketoconazoleSerious - Use Alternative (1)formoterol and levoketoconazole both increase QTc interval. Avoid or Use Alternate Drug.levorphanolMonitor Closely (1)levorphanol increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.linezolidSerious - Use Alternative (1)linezolid increases effects of formoterol by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.lisdexamfetamineMonitor Closely (2)formoterol and lisdexamfetamine both decrease sedation. Use Caution/Monitor. formoterol and lisdexamfetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.lofepramineMonitor Closely (1)lofepramine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use