Amoxicillin

Brand names

• Amoxil
• Moxatag
• Trimox

Uses

• Bacterial infections of the ear, nose, and throat (such as strep throat, tonsillitis, and ear infections)
• Respiratory tract infections including pneumonia and bronchitis
• Urinary tract infections
• Skin and soft tissue infections
• Helicobacter pylori infection (in combination with other medications to treat stomach ulcers)
• Dental infections
• Prevention of infection after certain dental or medical procedures in people at risk for heart valve infection

Dosage forms

• Immediate-release capsules (250 mg, 500 mg)
• Immediate-release tablets (500 mg, 875 mg)
• Chewable tablets (125 mg, 250 mg)
• Extended-release tablets (775 mg)
• Oral suspension liquid (125 mg/5 mL, 200 mg/5 mL, 250 mg/5 mL, 400 mg/5 mL)

Administration

Amoxicillin is taken by mouth and can be given with or without food. The liquid suspension should be shaken well before each use. Treatment duration typically ranges from 7 to 14 days depending on the type and severity of infection, though some infections may require shorter or longer courses. Extended-release tablets should be taken within one hour of finishing a meal and swallowed whole without crushing or chewing. It is important to complete the entire prescribed course of antibiotics even if symptoms improve before the medication is finished, as stopping early can lead to antibiotic resistance and infection recurrence. Only a healthcare provider can determine the appropriate dose and duration for your specific situation.

Common side effects

• Nausea or upset stomach
• Diarrhea or loose stools
• Vomiting
• Mild skin rash
• Headache
• Changes in taste

Serious side effects

• Severe allergic reactions (difficulty breathing, swelling of face, lips, tongue, or throat, hives)
• Severe skin reactions including blistering, peeling, or red skin rash
• Severe diarrhea that is watery or bloody, which may indicate a Clostridioides difficile infection
• Yellowing of skin or eyes (jaundice) indicating possible liver problems
• Dark urine or pale stools
• Unusual bruising or bleeding
• Severe stomach pain or cramping
• Seizures (especially in people with kidney problems taking high doses)

Warnings

• ALLERGY WARNING: Do not take amoxicillin if you have ever had an allergic reaction to penicillin antibiotics or cephalosporin antibiotics. Allergic reactions can be life-threatening. Tell your healthcare provider about all previous antibiotic allergies.
• This medication only treats bacterial infections and will not work for viral infections such as the common cold or flu. Using antibiotics when they are not needed increases the risk of developing antibiotic-resistant infections.
• Antibiotic use can cause diarrhea by affecting the normal bacteria in the intestines. Severe or persistent diarrhea may indicate a serious intestinal infection (C. difficile) that requires medical attention.
• People with kidney disease may need dose adjustments as amoxicillin is eliminated through the kidneys.
• Amoxicillin may reduce the effectiveness of birth control pills. Discuss additional contraceptive methods with your healthcare provider.
• Patients with infectious mononucleosis (mono) who take amoxicillin have a high risk of developing a skin rash.
• Long-term or repeated use may result in oral thrush or a new vaginal yeast infection due to changes in normal body bacteria.

Drug interactions

• Probenecid (increases amoxicillin blood levels)
• Allopurinol (may increase risk of skin rash)
• Methotrexate (amoxicillin may increase methotrexate levels)
• Warfarin and other blood thinners (amoxicillin may enhance anticoagulant effects)
• Oral contraceptives (birth control pills may be less effective)
• Live bacterial vaccines such as typhoid vaccine (antibiotics may reduce vaccine effectiveness)
• Other antibiotics, particularly bacteriostatic antibiotics like tetracyclines, which may interfere with amoxicillin's effectiveness

Contraindications

• Known severe allergic reaction (anaphylaxis) to amoxicillin, other penicillins, or any ingredient in the formulation
• History of amoxicillin-induced liver injury or jaundice
• Extended-release tablets are contraindicated in people with severe kidney impairment

Pregnancy notes

Amoxicillin is classified as Pregnancy Category B, meaning animal studies have not shown risk to the fetus, and it is generally considered safe for use during pregnancy when clearly needed. It is one of the antibiotics most commonly prescribed during pregnancy. However, pregnant individuals should always consult their healthcare provider before taking any medication. Amoxicillin passes into breast milk in small amounts but is generally considered compatible with breastfeeding. Nursing infants should be monitored for possible effects such as diarrhea, thrush, or diaper rash.

Storage

Store amoxicillin capsules and tablets at room temperature between 68°F to 77°F (20°C to 25°C), away from moisture, heat, and light. Keep the container tightly closed. Liquid suspension should be stored in the refrigerator after mixing and discarded after 14 days. Some formulations may be stored at room temperature—check the label or ask your pharmacist. Do not freeze liquid amoxicillin. Keep all medications out of reach of children and pets.

Frequently asked questions