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Patients taking the commonly prescribed antibiotic erythromycin (E.E.S., E.E.S. 400, ERY-TAB, ERYC, ERYPED) should be aware that it has clinically important and potentially dangerous interactions with many other prescription medications.
Initially approved by the Food and Drug Administration in 1967, erythromycin is a macrolide antibiotic, a family of drugs that also includes azithromycin (ZITHROMAX) and clarithromycin (BIAXIN XL). Erythromycin is approved for treating a variety of...
Patients taking the commonly prescribed antibiotic erythromycin (E.E.S., E.E.S. 400, ERY-TAB, ERYC, ERYPED) should be aware that it has clinically important and potentially dangerous interactions with many other prescription medications.
Initially approved by the Food and Drug Administration in 1967, erythromycin is a macrolide antibiotic, a family of drugs that also includes azithromycin (ZITHROMAX) and clarithromycin (BIAXIN XL). Erythromycin is approved for treating a variety of mild-to-moderate bacterial infections, including certain types of pneumonia, upper respiratory tract infections and skin infections, as well as diphtheria, acute pelvic inflammatory disease and syphilis.[1] It also is used to prevent recurring attacks of rheumatic fever due to strep throat in patients allergic to penicillin or sulfonamide antibiotics.
Depending on the infection being treated, erythromycin typically is prescribed for adults at dosages ranging from 250 to 1,000 milligrams four times daily for seven to 14 days.[2]
Increased risk of fatal heart rhythm abnormalities[3],[4]
Like other macrolide antibiotics, erythromycin can cause an increased risk of prolongation of the QT interval in the heart rhythm. QT prolongation is a change in the electrical activity of the heart that can lead to a potentially fatal heart rhythm disturbance called torsades de pointes, which can cause cardiac arrest and sudden death. Elderly patients are more susceptible to this adverse cardiac event.
Numerous oral drugs, when used concomitantly (at the same time) with erythromycin, further increase the risk of QT prolongation (see the Table, below, for examples). The list of such drugs includes certain medications for treating abnormal heart rhythms, Alzheimer’s disease, bacterial infections, depression, fungal infections, HIV infection, high blood pressure, opioid withdrawal and psychosis, among others. In some cases, the other interacting drug itself also causes QT prolongation, beyond that caused by erythromycin.
For many of these interacting drugs, the risk of QT prolongation and potentially fatal abnormal heart rhythms is so high that erythromycin should not be taken concomitantly with the interacting drugs.
Examples of Oral Drugs That Increase the Risk of Potentially Fatal Abnormal Heart Rhythms When Taken Concomitantly With Erythromycin
| Generic Name | Brand Name(s)† | Drug Class |
|---|---|---|
| amitriptyline* | generic only | Tricyclic antidepressant |
| amoxapine* | generic only | Tricyclic antidepressant |
| chloroquine** | generic only | Drug for malaria |
| ciprofloxacin** | CIPRO | Antibiotic |
| desipramine** | NORPRAMIN | Tricyclic antidepressant |
| diltiazem** | CARDIZEM, CARTIA XT, TAZTIA XT, TIAZAC | Calcium channel blocker for high blood pressure |
| disopyramide** | NORPACE | Abnormal heart rhythm drug |
| dofetilide | TIKOSYN | Abnormal heart rhythm drug |
| donepezil* | ARICEPT | Alzheimer’s disease drug |
| doxepin* | SILENOR | Tricyclic antidepressant |
| dronedarone* | MULTAQ | Abnormal heart rhythm drug |
| fluconazole | DIFLUCAN | Antifungal drug |
| fluoxetine** | PROZAC | Selective serotonin reuptake inhibitor (SSRI) antidepressant |
| gemifloxacin* | FACTIVE | Antibiotic |
| hydroxychloroquine** | PLAQUENIL | Drug for malaria, rheumatoid arthritis and lupus erythematosus |
| imipramine* | TOFRANIL | Tricyclic antidepressant |
| ketoconazole* | generic only | Antifungal drug |
| levofloxacin** | generic only | Antibiotic |
| lofexidine | LUCEMYRA | Opioid withdrawal syndrome drug |
| nortriptyline** | PAMELOR | Tricyclic antidepressant |
| posaconazole | NOXAFIL | Antifungal drug |
| quetiapine** | SEROQUEL | Antipsychotic |
| quinidine** | generic only | Abnormal heart rhythm drug |
| quinine | QUALAQUIN | Drug for malaria |
| saquinavir | INVIRASE | Antiviral drug for HIV infection |
| sertraline** | ZOLOFT | SSRI antidepressant |
| thioridazine* | generic only | Antipsychotic |
| vardenafil** | LEVITRA, STAXYN | Erectile dysfunction drug |
| verapamil | CALAN SR, VERELAN | Calcium channel blocker for high blood pressure |
| voclosporin | LUPKYNIS | Immunosuppressant for treating kidney disease due to lupus erythematosus |
| voriconazole | VFEND | Antifungal drug |
| ziprasidone* | GEODON | Antipsychotic |
†Brand-name combination products were excluded.
*Designated as Do Not Use by Worst Pills, Best Pills News
**Designated as Limited Use by Worst Pills, Best Pills News
Other important drug interactions[5],[6]
Cholesterol-lowering statins
Like many drugs, erythromycin can inhibit the activity of substances in the liver called enzymes that metabolize (break down or chemically modify) other drugs. For example, erythromycin can inhibit the liver enzymes that break down cholesterol-lowering statin drugs — including atorvastatin (LIPITOR), lovastatin (ALTOPREV), pitavastatin (LIVALO, ZYPITAMAG) and simvastatin (FLOLIPID, ZOCOR). Concomitant use of erythromycin with these statins can increase the risk of statin-induced myopathy (muscle damage). In severe cases, this condition can progress to rhabdomyolysis, a life-threatening, muscle-destroying condition that can lead to sudden kidney failure and death. For lovastatin and simvastatin, the risk of this dangerous interaction is so high that erythromycin should not be taken concomitantly with these two statins.
Digoxin (LANOXIN)
Concomitant use of erythromycin and digoxin — which is used to treat heart failure and to control heart rate in patients with atrial fibrillation (a common abnormal heart rhythm characterized by an irregular and often rapid heartbeat) — can result in increased blood levels of digoxin, potentially leading to serious digoxin toxicity. Common symptoms of digoxin toxicity are loss of appetite, nausea, vomiting and fatigue. Digoxin toxicity can lead to abnormal heart rhythms. If concomitant use of erythromycin and digoxin is unavoidable, more frequent monitoring of blood digoxin levels should occur, especially during initiation and discontinuation of erythromycin.
Warfarin (JANTOVEN)
Concomitant use of erythromycin and the anticoagulant (blood thinner) warfarin likewise can increase the anticoagulant effects of warfarin. This can increase the risk of bleeding complications. Ideally, concomitant use of these two drugs should be avoided. If such use is unavoidable, more frequent monitoring of warfarin levels should occur, especially during initiation and discontinuation of erythromycin.
What You Can Do
If you need treatment with erythromycin, review all your other medications with your doctor to assess for potentially significant drug interactions. If you are taking certain medications that interact with this antibiotic, you may need to reduce the dosage of the interacting drug or to take an alternative antibiotic, or your doctor may advise you to stop the interacting drug. Be aware that many other drugs not listed in this article also may have dangerous interactions with erythromycin.
References
[1] Arbor Pharmaceuticals , Inc. Label: erythromycin. October 2018. https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=ddd9ad9a-fc60-409a-a2b3-be51482ef751&type=display. Accessed April 9, 2021.
[2] Ibid.
[3] Ibid.
[4] IBM Micromedex. Drug interactions. http://www.micromedexsolutions.com/home/dispatch. Search term: “erythromycin.” Accessed March 23, 2021.
[5] Ibid.
[6] Arbor Pharmaceuticals , Inc. Label: erythromycin. October 2018. https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=ddd9ad9a-fc60-409a-a2b3-be51482ef751&type=display. Accessed April 9, 2021.
