Generic name: Dirithromycin.

Dynabac is a macrolide antibiotic in the same family as erythromycin. It is used to treat a variety of bacterial infections. 

Quick Facts About Dynabac


Used to treat several infections including flare-ups of chronic bronchitis, pneumonia, strep throat, tonsillitis.

Dynabac Dosage

Take exactly as prescribed, with food or within 1 hour after a meal. Swallow tablet whole; do not crush, chew, or break it. Continue taking prescription even if symptoms disappear; not finishing prescription may cause infection to return.

  • Usual adult dose: for bronchitis and skin infections — 500 milligrams (2 tablets) daily for 7 days. For pneumonia — 500 milligrams (2 tablets) daily for 14 days. For strep throat and tonsillitis — 500 milligrams (2 tablets) daily for 10 days.
  • Usual child dose: Not generally prescribed for children under 12 years.
  • Missed dose: take as soon as possible, unless almost time for next dose. In that case, do not take missed dose; go back to regular schedule. Do not double doses.

Dynabac Side Effects

Overdose symptoms:

diarrhea, nausea, stomach cramps, vomiting. If you suspect an overdose, immediately seek medical attention.

More common side effects: abdominal pain, diarrhea, loss of appetite, nausea, vomiting.

Less common Dynabac side effects: dizziness, gas, hives, increased cough, insomnia, itching, pain, rash, shortness of breath, stomach and intestinal disturbances, weakness. Rare side effects: abnormal stools, allergic reaction, anxiety, constipation, coughing up blood, dehydration, dry mouth, fainting, fever, fluid retention, flu-like symptoms, frequent urination, inflammation of the stomach and intestines, loss of appetite, mouth sores, muscle pain, neck pain, nervousness, nosebleeds, painful menstruation, “pins and needles,” pounding heartbeat, rapid breathing, reduced vision or other eye problems, ringing in ears, sleepiness, sweating, swelling of hands and feet, taste alteration, thirst tremor, vaginal fungus, vaginal inflammation.


Inform your doctor before combining Dynabac with:

astemizole (Hismanal); blood thinners such as Coumadin; bromocriptine (Parlodel); carbamazepine (Tegretol); cimetidine (Tagamet); cyclosporine (Sandimmune); digoxin (Lanoxin); disopyramide (Norpace); ergotamine (Cafergot); lovastatin (Mevacor); phenytoin (Dilantin); ranitidine (Zantac); terfenadine (Seldane); theophylline (Theo-Dur); triazolam (Halcion); valproic acid (Depakene or Depakote).

Do not combine Dynabac with antacids (Maalox or Mylanta). 

Special Cautions

If pregnant or planning to become pregnant, inform ? your doctor immediately. Appears in breast milk; could affect a nursing infant

No special precautions apply to seniors.

Follow doctor’s instructions carefully for children.

  • Should not use if sensitive or allergic to this medication or similar antibiotics such as erythromycin. Inform your doctor of any other allergies.
  • Inform your doctor before taking Dynabac if you have or had liver disease.
  • Combining Dynabac with certain medications could cause serious, life-threatening effects. Do not combine with other erythromycin-type antibiotics, with Seldane, or with Hismanal, especially if you have a heart condition such as irregular heartbeat rhythms.


HealthSurvey.org provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Dynabac side effects, please contact your healthcare provider.