Amoxicillin

Description

Amoxicillin capsules, USP, are semisynthetic antibacterial agents derived from ampicillin, exhibiting a broad spectrum of bactericidal activity against various Gram-positive and Gram-negative microorganisms. The chemical structure of amoxicillin is defined as (2S,5R,6R)-6-((R)-(-)-2-amino-2-(p-hydroxyphenyl)acetamido-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo3.2.0heptane-2-carboxylic acid trihydrate. The molecular formula is C16H19N3O5S•3H2O, with a molecular weight of 419.45.

Each capsule is available in two strengths: 250 mg and 500 mg of amoxicillin USP as the trihydrate. The 250 mg capsule features a blue cap and a pink body, with the body imprinted with ‘A44’ in black ink. The 500 mg capsule also has a blue cap and a pink body, marked with ‘A45’ in black ink. Inactive ingredients include D&C Red No. 28, FD&C Blue No. 1, FD&C Red No. 40, gelatin, magnesium stearate, microcrystalline cellulose, sodium lauryl sulfate, and titanium dioxide. Amoxicillin capsules meet the USP Dissolution Test 2 criteria.

Uses and Indications

Amoxicillin capsules are indicated for the treatment of infections caused by susceptible strains of designated microorganisms. This medication is specifically indicated for the following conditions:

• Upper Respiratory Tract Infections of the Ear, Nose, and Throat

• Infections of the Genitourinary Tract

• Infections of the Skin and Skin Structure

• Infections of the Lower Respiratory Tract

• Helicobacter pylori Infection and Duodenal Ulcer Disease in adult patients only

Amoxicillin capsules should be utilized exclusively for the treatment or prevention of infections that are proven or strongly suspected to be bacterial in origin. This approach is essential to minimize the development of drug-resistant bacteria and to preserve the efficacy of amoxicillin capsules and other antibacterial agents.

Dosage and Administration

In adults, the recommended dosage ranges from 750 mg to 1750 mg per day, administered in divided doses every 8 to 12 hours. For pediatric patients over 3 months of age, the dosage is 20 mg to 45 mg per kilogram of body weight per day, also given in divided doses every 8 to 12 hours. Healthcare professionals should refer to the full prescribing information for specific dosing regimens tailored to individual patient needs.

For neonates and infants aged 3 months or younger, the upper limit of dosing is 30 mg per kilogram of body weight per day, divided and administered every 12 hours.

In the treatment of H. pylori infection in adults, two therapeutic regimens are recommended. The triple therapy consists of 1 gram of amoxicillin, 500 mg of clarithromycin, and 30 mg of lansoprazole, all administered twice daily (every 12 hours) for a duration of 14 days. Alternatively, the dual therapy includes 1 gram of amoxicillin and 30 mg of lansoprazole, each given three times daily (every 8 hours) for 14 days.

It is essential to reduce the dosage in patients with severe renal impairment, specifically those with a glomerular filtration rate (GFR) greater than 30 mL/min.

Contraindications

Use is contraindicated in patients with a history of serious hypersensitivity reactions, such as anaphylaxis or Stevens-Johnson syndrome, to amoxicillin capsules or other beta-lactams, including penicillins or cephalosporins.

Warnings and Precautions

Serious and occasionally fatal anaphylactic reactions have been reported in patients receiving penicillin therapy, including amoxicillin. It is imperative that healthcare professionals discontinue amoxicillin immediately if any signs of an anaphylactic reaction occur.

Severe cutaneous adverse reactions (SCAR) have also been associated with amoxicillin use. Patients should be monitored closely for the development of rashes, and amoxicillin should be discontinued if the rash progresses.

Additionally, drug-induced enterocolitis syndrome (DIES) has been documented in patients taking amoxicillin. In the event that DIES is suspected, it is essential to discontinue amoxicillin and initiate appropriate therapeutic measures.

Clostridioides difficile-associated diarrhea (CDAD) can manifest in a spectrum ranging from mild diarrhea to severe, potentially fatal colitis. Healthcare professionals should evaluate patients for CDAD if diarrhea occurs during or after treatment with amoxicillin.

Side Effects

Patients receiving amoxicillin may experience a range of adverse reactions, which can be categorized into common and serious reactions.

Common adverse reactions include diarrhea, rash, vomiting, and nausea. These reactions are generally mild and may not require discontinuation of therapy.

Serious adverse reactions have been reported and necessitate immediate medical attention. Anaphylactic reactions, which can be serious and occasionally fatal, have been documented in patients undergoing penicillin therapy, including amoxicillin. In the event of an anaphylactic reaction, amoxicillin should be discontinued promptly. Additionally, severe cutaneous adverse reactions (SCAR) have been observed; patients should be monitored closely, and amoxicillin should be discontinued if any rash progresses. Drug-induced enterocolitis syndrome (DIES) has also been reported in association with amoxicillin use, and if this condition occurs, amoxicillin should be discontinued, and appropriate therapy should be initiated. Clostridioides difficile-associated diarrhea (CDAD) can range from mild diarrhea to severe, potentially fatal colitis, and evaluation is warranted if diarrhea develops.

It is important to note that patients with a history of serious hypersensitivity reactions, such as anaphylaxis or Stevens-Johnson syndrome, to amoxicillin capsules or other beta-lactams (including penicillins or cephalosporins) may be at increased risk for adverse reactions.

Overdosage of amoxicillin has been associated with serious complications, including interstitial nephritis leading to oliguric renal failure, which has been reported in a small number of patients. Crystalluria, which in some cases has resulted in renal failure, has also been documented following overdosage in both adult and pediatric patients.

Drug Interactions

Co-administration of amoxicillin with probenecid is not recommended due to potential interactions that may affect the pharmacokinetics of amoxicillin.

When amoxicillin is used concurrently with oral anticoagulants, there is an increased risk of prolongation of prothrombin time. It is advisable to monitor prothrombin time closely in patients receiving this combination to ensure safe anticoagulation levels.

The concomitant use of amoxicillin and allopurinol has been associated with an increased risk of rash. Clinicians should be vigilant for dermatological reactions in patients receiving both medications.

Additionally, amoxicillin may reduce the efficacy of oral contraceptives. Patients should be counseled on the potential need for alternative or additional contraceptive methods while taking amoxicillin to ensure effective pregnancy prevention.

Packaging & NDC

The table below lists all NDC Code configurations of Amoxicillin, the U.S. brand-name prescription product. Columns show Packaging, Formulation Type, and Active Ingredient Strength.

Pediatric Use

The safety and effectiveness of amoxicillin have been established for the treatment of upper respiratory tract infections, as well as infections of the genitourinary tract, skin and skin structure, and lower respiratory tract in pediatric patients. However, the safety and effectiveness of amoxicillin for the treatment of H. pylori infection have not been established in this population.

In pediatric patients aged 12 weeks or younger (3 months or younger), caution is advised due to incompletely developed renal function, which may delay the elimination of amoxicillin. Therefore, dosing should be modified accordingly in this age group to ensure safety and efficacy.

Geriatric Use

An analysis of clinical studies of amoxicillin has been conducted to evaluate the response of subjects aged 65 and over compared to younger subjects. The findings from these analyses did not identify significant differences in responses between elderly patients and their younger counterparts; however, it is important to note that a greater sensitivity to the drug in some older individuals cannot be ruled out.

Amoxicillin is substantially excreted by the kidneys, which raises concerns regarding the risk of toxic reactions, particularly in patients with impaired renal function. Given that geriatric patients are more likely to experience decreased renal function, careful consideration should be given to dose selection in this population. It may be beneficial to monitor renal function in elderly patients to mitigate potential risks associated with the use of this medication.

Pregnancy

Amoxicillin is classified as Pregnancy Category B. Reproduction studies conducted in mice and rats at doses up to 2000 mg/kg, which is 3 and 6 times the human dose of 3 g based on body surface area, have shown no evidence of harm to the fetus. However, there are no adequate and well-controlled studies in pregnant women.

Due to the limitations of animal reproduction studies in predicting human response, amoxicillin should be used during pregnancy only if clearly needed. Healthcare professionals are advised to weigh the potential benefits against any possible risks when considering the use of amoxicillin in pregnant patients.

Lactation

Penicillins, including amoxicillin, have been shown to be excreted in human milk. The use of amoxicillin by nursing mothers may lead to sensitization of breastfed infants. Therefore, caution should be exercised when administering amoxicillin to lactating mothers.

Renal Impairment

There is no specific information available regarding dosage adjustments, special monitoring, or safety considerations for patients with renal impairment. Healthcare professionals should exercise caution when prescribing to patients with reduced kidney function, as the absence of detailed guidance necessitates careful clinical judgment. Regular monitoring of renal function may be advisable in this patient population.

Hepatic Impairment

Patients with hepatic impairment have not been specifically studied in relation to the use of this medication. Consequently, there are no established dosage adjustments, special monitoring requirements, or precautions outlined for individuals with compromised liver function. It is recommended that healthcare providers exercise caution when prescribing this medication to patients with hepatic impairment, given the lack of data on its safety and efficacy in this population. Regular monitoring of liver function may be prudent in these cases, although specific parameters are not defined in the available information.

Overdosage

In the event of amoxicillin overdosage, it is imperative to discontinue the medication immediately. Symptomatic treatment and supportive measures should be instituted as necessary to manage the patient's condition effectively.

A prospective study involving 51 pediatric patients at a poison-control center indicated that overdosages of amoxicillin below 250 mg/kg typically do not result in significant clinical symptoms. However, healthcare professionals should remain vigilant for potential adverse effects.

Notably, interstitial nephritis leading to oliguric renal failure has been documented in a limited number of cases following amoxicillin overdosage. Additionally, crystalluria, which may progress to renal failure, has been reported in both adult and pediatric populations. To mitigate the risk of crystalluria, it is essential to ensure adequate fluid intake and maintain diuresis in affected patients.

Renal impairment associated with amoxicillin overdosage appears to be reversible upon cessation of the drug. It is important to note that patients with pre-existing renal dysfunction may experience elevated blood levels of amoxicillin due to reduced renal clearance. In such cases, hemodialysis may be employed to facilitate the removal of amoxicillin from the circulation.

Nonclinical Toxicology

Long-term studies in animals have not been performed to evaluate the carcinogenic potential of the compound. While specific studies to detect the mutagenic potential of amoxicillin alone have not been conducted, data from tests on a 4:1 mixture of amoxicillin and potassium clavulanate provide relevant insights.

The combination of amoxicillin and potassium clavulanate was found to be non-mutagenic in both the Ames bacterial mutation assay and the yeast gene conversion assay. However, it exhibited weakly positive results in the mouse lymphoma assay, where the observed trend toward increased mutation frequencies occurred at doses that were also associated with decreased cell survival. In contrast, the mixture was negative in the mouse micronucleus test and the dominant lethal assay in mice.

Potassium clavulanate alone was evaluated in the Ames bacterial mutation assay and the mouse micronucleus test, yielding negative results in both assays, indicating no mutagenic potential.

In a multi-generation reproduction study conducted in rats, no impairment of fertility or other adverse reproductive effects were observed at doses up to 500 mg/kg, which is approximately twice the human dose of 3 g based on body surface area.

Postmarketing Experience

Postmarketing experience has identified several adverse reactions reported voluntarily or through surveillance programs. These include anaphylaxis, serious skin reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis, and hepatic dysfunction characterized by cholestatic jaundice and hepatitis. Additionally, renal impairment, including interstitial nephritis, has been noted.

Hematologic reactions, including thrombocytopenia, leukopenia, and hemolytic anemia, have also been reported. Cases of Clostridium difficile-associated diarrhea and various allergic reactions, such as angioedema and urticaria, were documented. Other reactions observed include seizures and hyperactivity in pediatric patients.

It is important to note that these adverse reactions were reported during postmarketing surveillance and may not be directly related to the use of amoxicillin.

Patient Counseling

Healthcare providers should advise patients that amoxicillin may be taken every 8 hours or every 12 hours, depending on the prescribed dosage. It is important to counsel patients that amoxicillin is a penicillin class drug, which can cause allergic reactions in some individuals.

Patients should be informed about the signs and symptoms of serious skin manifestations. They should be instructed to stop taking amoxicillin immediately and promptly report any signs or symptoms of skin rash, mucosal lesions, or other indications of hypersensitivity.

Additionally, healthcare providers should counsel patients that diarrhea is a common side effect associated with antibacterial drugs, typically resolving upon discontinuation of the medication. However, patients should be made aware that they may develop watery and bloody stools (with or without stomach cramps and fever) even as late as 2 or more months after their last dose of the antibacterial drug. In such cases, patients should be advised to contact their physician as soon as possible.

It is essential to inform patients that antibacterial drugs, including amoxicillin, are intended solely for the treatment or prevention of bacterial infections and do not address viral infections, such as the common cold. When prescribed amoxicillin for a bacterial infection, patients should be reminded that it is common to feel better early in the treatment course; however, the medication must be taken exactly as directed. Skipping doses or failing to complete the full course of therapy may decrease the effectiveness of the immediate treatment and increase the likelihood of bacteria developing resistance, rendering them untreatable by amoxicillin or other antibacterial drugs in the future.

Storage and Handling

The product is supplied in a blister pack configuration. It is essential to store the product at a temperature range of 20° to 25°C (68° to 77°F), with permissible excursions between 15° to 30°C (59° to 86°F) as defined by USP Controlled Room Temperature guidelines.

Healthcare professionals should ensure that the blister pack remains intact; the product must not be used if the blister is torn or broken. Proper handling and storage conditions are crucial to maintain the integrity and efficacy of the product.

Additional Clinical Information

No further data are available.

FDA Insert (PDF)

This document is the official FDA-approved prescribing information for Amoxicillin as submitted by American Health Packaging. It includes detailed information about indications, dosage, contraindications, warnings, and clinical pharmacology.

View full prescribing information (PDF)