Amoxicillin vs. ceftriaxone: What's the difference?

What is amoxicillin? What is ceftriaxone?

Amoxicillin is a penicillin-type antibiotic, the same class that includes piperacillin (Pipracil), ampicillin (Unasyn), and ticarcillin (Ticar). Penicillin-type antibiotics do not directly kill bacteria, but they stop bacteria from multiplying by preventing bacteria from forming the walls that surround them. The walls protect bacteria from their environment and keep the contents of the bacterial cell together. Bacteria cannot survive without a cell wall. Amoxicillin is effective against many different bacteria including H. influenzae, E. coli, Pneumococci, N. gonorrhoea, Streptococci, and some strains of Staphylococci. Amoxicillin is used to treat bacterial infections of the middle ear, tonsils, throat, larynx (laryngitis), lungs (pneumonia), bronchi (bronchitis), urinary tract, and skin. Amoxicillin also is used to treat gonorrhea.

Ceftriaxone is a cephalosporin antibiotic used to treat a wide variety of bacterial infections such as lower respiratory tract infections, skin and skin structure infections, urinary tract infections, pelvic inflammatory disease, bacterial septicemia, bone and joint infections, and meningitis. It works by stopping the growth of bacteria.

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Bacterial Infections 101: Types, Symptoms, and Treatments See Slideshow

What are the side effects of amoxicillin and ceftriaxone?

Amoxicillin

Side effects due to amoxicillin include

People who are allergic to the cephalosporin class of antibiotics, which are related to the penicillins, for example, cefaclor (Ceclor), cephalexin (Keflex), and cefprozil (Cefzil), may or may not be allergic to penicillins.

Serious but rare reactions include:

Amoxicillin can alter the normal bacteria in the colon and encourage overgrowth of some bacteria such as Clostridium difficile which causes inflammation of the colon (pseudomembranous colitis). Patients who develop signs of pseudomembranous colitis after starting amoxicillin (diarrhea, fever, abdominal pain, and possibly shock) should contact their physician immediately.

Ceftriaxone

You should not use this medicine if you have ever had a severe allergic reaction to ceftriaxone or any other cephalosporin antibiotic. Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction(fever, sore throat, burning in your eyes, skin pain, red or purple skin rash that spreads and causes blistering and peeling).

Call your doctor at once if you have:

  • a seizure (convulsions);
  • severe stomach pain, diarrhea that is watery or bloody;
  • sudden weakness or ill feeling, fever, chills, cold or flu symptoms, mouth sores;
  • pale or yellowed skin, dark colored urine;
  • severe pain in your upper stomach that comes and goes or spreads to your back;
  • a blood cell disorder--skin rash or tight feeling, severe tingling or numbness, pain, muscle weakness; or
  • kidney or bladder problems--pain in your side or lower back spreading to your groin, blood in your urine, painful or difficult urination, little or no urine.

Common side effects may include:

  • mild diarrhea;
  • warmth, tight feeling, or a hard lump where the injection was given;
  • vaginal itching or discharge;
  • rash; or
  • abnormal liver function tests.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is the dosage of amoxicillin vs. ceftriaxone?

Amoxicillin

  • For most infections in adults the dose of amoxicillin is 250 mg every 8 hours, 500 mg every 8 hours, 500 mg every 12 hours or 875 mg every 12 hours, depending on the type and severity of infection.
  • For the treatment of adults with gonorrhea, the dose is 3 g given as one dose.
  • For most infections, children older than 3 months but less than 40 kg are treated with 25 or 45 mg/kg/day in divided doses every 12 hours or 20 or 40 mg/kg/day with one-third of the daily dose given every 8 hours depending on the type and severity of the infection.
  • Amoxicillin can be taken with or without food.

Ceftriaxone

  • The usual adult daily dose is 1 to 2 grams given once a day (or in equally divided doses twice a day) depending on the type and severity of infection. The total daily dose should not exceed 4 grams.
  • Ceftriaxone is injected into a muscle, or into a vein through an IV.
  • A healthcare provider will give you this injection when ceftriaxone is used to prevent infection from surgery.
  • You may be shown how to use an IV at home to treat an infection. Do not give yourself this medicine if you do not understand how to use the injection and properly dispose of needles, IV tubing, and other items used.
  • Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended.

QUESTION

Bowel regularity means a bowel movement every day. See Answer

What drugs interact with amoxicillin and ceftriaxone?

Amoxicillin

Amoxicillin is rarely associated with important drug interactions.

Ceftriaxone

Rocephin must not be administered simultaneously with calcium-containing IV solutions, including continuous calcium-containing infusions such as parenteral nutrition via a Y-site. However, in patients other than neonates, Rocephin and calcium-containing solutions may be administered sequentially of one another if the infusion lines are thoroughly flushed between infusions with a compatible fluid.

Other drugs may interact with ceftriaxone, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

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Are amoxicillin and ceftriaxone safe to use while pregnant or breastfeeding?

Amoxicillin

  • Penicillins are generally considered safe for use by pregnant women who are not allergic to penicillin.
  • Small amounts of amoxicillin may be excreted in breast milk and may cause diarrhea or allergic responses in nursing infants. Amoxicillin is generally considered safe to use while breastfeeding. Amoxicillin is used to treat infections in the newborn.

Ceftriaxone

  • Reproductive studies have been performed in mice and rats at doses up to 20 times the usual human dose and have no evidence of embryotoxicity, fetotoxicity or teratogenicity. In primates, no embryotoxicity or teratogenicity was demonstrated at a dose approximately 3 times the human dose.
  • There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
  • Low concentrations of ceftriaxone are excreted in human milk. Caution should be exercised when Rocephin is administered to a nursing woman.

Summary

Amoxicillin (Amoxil) and ceftriaxone (Rocephin) are antibiotics used to treat bacterial infections of the middle ear, tonsils, throat, respiratory tract, urinary tract, and skin. Amoxicillin is also used to treat gonorrhea. Ceftriaxone is also used to treat pelvic inflammatory disease, bacterial septicemia, bone and joint infections, and meningitis.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 5/30/2019
References
FDA Prescribing Information.

Some content about ceftriaxone is used courtesy of the U.S. Food and Drug Administration
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