Amoxicillin

What it is and how it works

Mechanism of Action Amoxicillin is an antibacterial drug .

Indications

Adults and Pediatric Patients Upper Respiratory Tract Infections of the Ear, Nose, and Throat: Amoxicillin tablets, amoxicillin for oral suspension, amoxicillin tablets (chewable), and amoxicillin capsules are indicated in the treatment of infections due to susceptible (ONLY β-lactamase-negative) isolates of Streptococcus species. (α- and β-hemolytic isolates only), Streptococcus pneumoniae , Staphylococcus spp., or Haemophilus influenzae . Infections of the Genitourinary Tract: Amoxicillin tablets, amoxicillin for oral suspension, amoxicillin tablets (chewable), and amoxicillin capsules are indicated in the treatment of infections due to susceptible (ONLY β-lactamase-negative) isolates of Escherichia coli , Proteus mirabilis , or Enterococcus faecalis . Infections of the Skin and Skin Structure: Amoxicillin tablets, amoxicillin for oral suspension, amoxicillin tablets (chewable), and amoxicillin capsules are indicated in the treatment of infections due to susceptible (ONLY β-lactamase-negative) isolates of Streptococcus spp.

Dosage and administration (summary)

In Adults, 750 to 1750 mg/day in divided doses every 8 to 12 hours. In Pediatric Patients over 3 Months of Age, 20 to 45 mg/kg/day in divided doses every 8 to 12 hours. Refer to full prescribing information for specific dosing regimens. ( 2.2 , 2.3 ) The upper dose for neonates and infants aged 3 months or younger is 30 mg/kg/day divided every 12 hours. Dosing for H. pylori Infection (in Adults): Triple therapy: 1 gram amoxicillin, 500 mg clarithromycin, and 30 mg lansoprazole, all given twice daily (every 12 hours) for 14 days. Dual therapy: 1 gram amoxicillin and 30 mg lansoprazole, each given three times daily (every 8 hours) for 14 days.

Contraindications

Amoxicillin is contraindicated in patients who have experienced a serious hypersensitivity reaction (e.g., anaphylaxis or Stevens-Johnson syndrome) to amoxicillin or to other β-lactam antibacterial drugs (e.g., penicillins and cephalosporins). History of a serious hypersensitivity reaction (e.g., anaphylaxis or Stevens-Johnson syndrome) to amoxicillin or to other beta-lactams (e.g., penicillins or cephalosporins).

Warnings and precautions

Anaphylactic reactions: Serious and occasionally fatal anaphylactic reactions have been reported in patients on penicillin therapy, including amoxicillin. Discontinue amoxicillin if a reaction occurs . Severe cutaneous adverse reactions (SCAR): Monitor closely. Discontinue if rash progresses. Drug-induced enterocolitis syndrome (DIES) has been reported with amoxicillin use. If this occurs, discontinue amoxicillin and institute appropriate therapy. Clostridioides difficile -associated diarrhea (CDAD) (ranging from mild diarrhea to fatal colitis): Evaluate if diarrhea occurs.

Pregnancy

Pregnancy Teratogenic Effects : Pregnancy Category B. Reproduction studies have been performed in mice and rats at doses up to 2000 mg/kg (3 and 6 times the 3 g human dose, based on body surface area). There was no evidence of harm to the fetus due to amoxicillin. There are, however, no adequate and well-controlled studies in pregnant women.

Storage and supply

Amoxicillin tablets, USP: Amoxicillin Tablets (Chewable), USP: 250 mg : Each white to off-white, capsule-shaped tablet, debossed 93 (partial bisect between 9 and 3) on one side and 2268 on the other side and contain 250 mg amoxicillin, USP as the trihydrate. They are available in bottles of 4 tablets (NDC 43063-341-04).

Source: Amoxicillin (Amoxicillin) — US FDA prescribing information, 2025-07-17, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.