This medication is an antibiotic given by vein (IV) to treat certain bacterial infections when medications cannot be taken by mouth. This medication is known as a macrolide (erythromycin-type) antibiotic. It works by stopping the growth of bacteria. This antibiotic treats only bacterial infections. It will not work for viral infections (e.g., common cold, flu). Unnecessary use or overuse of any antibiotic can lead to its decreased effectiveness. How to use Erythrocin IV This medication is mixed in the correct fluid and given slowly into a vein by a health care professional. Follow all instructions for proper mixing, dilution, and use. Consult your pharmacist if you are unclear on any instructions. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Do not inject the medication undiluted into a vein. Do not inject this medication into a muscle or under the skin. Do not mix erythromycin with other medications in the same IV fluid or give with other medications into the same vein at the same time. Antibiotics work best when used regularly. Erythromycin may be given continuously or slowly over 20-60 minutes as separate doses at evenly spaced intervals, usually every 6 hours, to make sure there is a constant level of medication in your blood. You should use this injectable medication only until you are able to take an antibiotic by mouth or until your treatment is finished. Dosage and length of treatment are based on your medical condition and response to therapy. Continue to use this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may allow bacteria to continue to grow, resulting in a return of the infection. Notify your doctor if your condition/symptoms do not improve or if they worsen.