Amoxicillin dosage, forms, and strengths

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The dosages listed are general guidelines; your healthcare provider may adjust your dose based on individual health factors.

Amoxicillin is a generic penicillin antibiotic that is FDA-approved to treat bacterial infections of the nose, sinuses, throat, ear, lungs, skin, and urinary tract. Healthcare providers often prescribe amoxicillin off-label for a wide variety of other infections, including Lyme disease, anthrax, chlamydia, gum infections, and dental abscesses. Pediatric doses are usually the same as adult doses unless the child weighs less than 40 kg (88 pounds). 

Amoxicillin dosage for strep throat or tonsillitis

For susceptible streptococcal infections of the tonsils or throat (pharynx), amoxicillin is given in high doses (1 g/day) until the infection clears, typically 10 days. Children are dosed by weight if they weigh less than 40 kg (88 pounds).

Amoxicillin dosage for sinusitis

For bacterial infections of the sinuses, the standard amoxicillin dosage is 500 mg twice daily or 250 mg three times daily. For severe infections, the dose may be higher. The first-line therapy for sinusitis, however, is amoxicillin/clavulanate due to high levels of bacterial resistance.

Amoxicillin dosage for acute otitis media

Otitis media is a bacterial infection of the middle ear, or the space between the eardrum and the inner ear. Amoxicillin is typically given for five to ten days or until the infection clears. Because of bacterial resistance, people with recurrent ear infections are more likely to receive amoxicillin/clavulanate.

Amoxicillin dosage for lower respiratory tract infections

Lung infections caused by non-resistant (beta-lactam susceptible) bacteria can be treated with amoxicillin. Lung infections caused by more resistant bacteria are more likely to be treated by amoxicillin/clavulanate, macrolides, or cephalosporins. The standard dose for adults is 875 mg taken twice daily or 500 mg taken three times daily.

Amoxicillin dosage for community-acquired pneumonia

Pneumonia caught outside a hospital is called community-acquired pneumonia. It is frequently caused by penicillin-susceptible bacteria. Pneumonia can be mild to severe, but severe cases can be life-threatening. For this reason, healthcare professionals use very high doses, usually 1 gram taken every eight hours for at least five days. 

Amoxicillin dosage for urinary tract infections

Infections of the genitourinary tract caused by penicillin-susceptible bacteria can be treated by amoxicillin in standard or high doses, depending on the severity of the infection or bacterial resistance. As with many other common bacterial infections, amoxicillin/clavulanate is the recommended drug of choice because of bacterial resistance.

Amoxicillin dosage for skin and skin structure infections

For bacterial infections of the skin, such as cellulitis, amoxicillin is given at standard or high doses depending on the severity of the infection and the degree of bacterial resistance.

Amoxicillin dosage for

Helicobacter pylori is a bacterium that infects the stomach lining. Often symptomless, the infection can damage the stomach lining and lead to gastritis (swelling of the stomach lining), stomach ulcers, duodenal ulcers, and stomach cancer. Dual therapy treatment consists of a stomach acid reducer (lansoprazole) and high doses of amoxicillin (1 gram taken three times daily). Triple therapy adds another antibiotic, such as clarithromycin, metronidazole, or levofloxacin. Doctors may add bismuth subsalicylate to reduce inflammation and protect the stomach lining. 

Amoxicillin safety info

Amoxicillin is a safe medication with relatively mild side effects. When people have side effects from amoxicillin, they typically involve mild gastrointestinal complaints. These are often resolved by taking amoxicillin with food. Treatment can be stopped at any time without causing adverse effects related to withdrawal. 

Amoxicillin should not be given to people who have had a severe allergic reaction, such as anaphylaxis, to amoxicillin or similar antibiotics called beta-lactam antibiotics. These include penicillins, cephalosporins, carbapenems, and monobactams. Mild reactions, such as skin rash, are not necessarily contraindications, but the doctor may consider using another antibiotic.

Amoxicillin is safe to take during pregnancy. Doctors use it cautiously in women who are breastfeeding. 

Because amoxicillin is eliminated almost entirely by the kidneys, people with renal impairment may need lower doses. People with liver problems (hepatic impairment) can take amoxicillin at normal doses.

Patients with renal impairment (kidney disease)—dose amount and frequency adjustment: 

• Creatinine clearance of >30 mL/min: no dose adjustment

• Creatinine clearance between 10 and 30 mL/min: 250-500 mg every 12 hours

• Creatinine clearance < 10 mL/min: 250-500 mg every 24 hours

• Hemodialysis: 250-500 mg every 24 hours with an additional dose given during and at the end of the dialysis treatment

• Parenteral dialysis: 250-500 mg every 24 hours

Amoxicillin’s most significant drug interactions include: 

• Birth control pills: Women taking oral contraceptives may need to use other forms of birth control.

• Blood thinners: Amoxicillin increases the risk of bleeding episodes.

• Live bacterial vaccines, such as typhoid vaccine or BCG (a tuberculosis vaccine): Antibiotics make live bacterial vaccines less effective.

• The gout medication allopurinol: Allopurinol increases the risk of serious hypersensitivity reactions to amoxicillin.

Amoxicillin dosage for pets

Both amoxicillin and amoxicillin-clavulanate are widely used to treat susceptible bacterial infectious diseases in domestic animals. Amoxicillin can be given as an oral tablet, but veterinarians sometimes give pets an intramuscular, intravenous, or subcutaneous injection. Doses, dose frequency, and duration of treatment vary by animal species, weight of the animal, and type of infection. 

How to take amoxicillin

No matter what the dosage form is, amoxicillin is taken by mouth two to three times a day. Spread the doses as evenly as possible across the day. Unless instructed otherwise, amoxicillin can be taken with or without food. 

• Take the medicine for the full prescribed duration, even if symptoms go away before the treatment has finished. Otherwise, the infection may come back.

• Store this medicine at room temperature (68–77°F) in a tightly sealed, light-resistant container. The oral solution can be stored in a refrigerator, but do not freeze it.

Capsules & Tablets

• Swallow the capsule or tablet whole with a full glass of water. Do not crush, break, open, or chew it.

Chewable tablets

• Completely chew the tablets before swallowing them.

• The chewable tablet can be crushed and then mixed with food for easier administration. The mixture should be consumed immediately.

Oral Suspension

• Shake the mixture well before giving a dose.

• When taking or giving the oral suspension, always use the measuring device supplied with the medicine to measure a dose. 

• The measured dose can be mixed with water, baby formula, milk, juice, ginger ale, or any other cold drink for easier administration. The entire mixture needs to be consumed immediately.

• Discard the oral solution after 14 days. 

Amoxicillin dosage FAQs

Amoxicillin vs. amoxicillin XR: What’s the difference in doses?

Extended-release (XR) amoxicillin is not sold in the U.S. Extended-release amoxicillin/clavulanate can be purchased as a generic prescription drug to treat community-acquired pneumonia or bacterial sinusitis. 

How long does amoxicillin take to work?

Amoxicillin starts killing bacteria on the first day of treatment. Symptoms usually improve in one or two days. However, it will take several days to completely eradicate the infection. 

Is a 5-day course of amoxicillin enough?

Most mild-to-moderate infections should clear up within five to ten days, but stubborn infections may take as long as 14 days to completely disappear. Although treatment duration varies, healthcare providers usually prescribe amoxicillin until symptoms are completely gone for at least 48 to 72 hours to ensure the infection has been eradicated.

Should I take amoxicillin 500 mg for seven or 10 days?

Take 500 mg amoxicillin for as long as the healthcare provider prescribes it, typically five, seven, or 10 days, depending on the type of infection. Severe infections may require longer treatment.

How many doses of amoxicillin for strep throat are needed to feel better?

Healthcare providers typically prescribe amoxicillin for 10 days to treat strep throat. Doses are taken two or three times a day. Although you may begin to feel better within a few days, it is important to take it for the prescribed duration of time to completely get rid of the infection and reduce antibiotic resistance.

Sources:

• Amoxicillin, StatPearls (2023)

• Amoxicillin tablet, film-coated, DailyMed (2024)

• Amoxil, Prescribers’ Digital Reference

• Beta-lactam antibiotics, StatPearls (2023)

• Plumb’s Veterinary Drug Handbook, 7th edition, Donald C. Plumb (2011)