Amoxicillin

1. Health Canada Product Monograph — Amoxicillin

• Treats infections of the ear, nose, and throat, urinary tract, skin and soft tissue, and lower respiratory tract, including acute otitis media, caused by susceptible bacteria.
• Also used as prophylaxis against bacterial endocarditis or streptococcal infection before certain dental, oral, or upper respiratory tract procedures in appropriate patients.
• Not active against Pseudomonas aeruginosa or many indole-positive Proteus, Serratia, Klebsiella, or Enterobacter species.

• Safety in pregnancy has not been formally established in this monograph; use only if the potential benefit to the mother justifies the possible risk to the fetus.

• This monograph does not include a dedicated breastfeeding section.
• Penicillin-class antibiotics such as amoxicillin are generally considered compatible with breastfeeding in usual doses; watch the infant for diarrhea or oral thrush and confirm with the current product information if concerned.

• No specific dosing precautions are listed for older adults, but because amoxicillin is substantially excreted by the kidney and elderly patients are more likely to have reduced renal function, careful dose selection and renal function monitoring are advised.

• Pediatric dosing is weight-based (mg/kg/day in divided doses) for children under 20 kg, with children at or above 20 kg dosed according to adult recommendations.
• A moderate, usually inconsequential rise in liver enzymes has been noted, particularly in infants; drug-induced enterocolitis syndrome, an allergic reaction causing repeated vomiting without skin or respiratory symptoms, has been reported mainly in children.

• Typical adult dosing is 250 mg every 8 hours for standard infections or 500 mg every 8 hours for more severe infections, as directed by the prescriber for the specific infection being treated.
• Complete the full prescribed course even if symptoms improve early, and expect the dose or interval to be adjusted in patients with significant renal impairment.

If overdose is suspected, seek emergency medical attention immediately or contact your regional Poison Control Centre without delay.

• Amoxicillin overdose is usually low risk for people with normal kidney function.
• Crystalluria (crystal formation in the urine) can occur and, in rare cases, has progressed to kidney failure.
• People with significantly reduced kidney function are most likely to need treatment after an overdose.
• Hemodialysis is the main treatment for a significant overdose, since it effectively clears amoxicillin from the blood.
• Activated charcoal may be given to limit further absorption of the drug.
• General supportive care is recommended.

• Amoxicillin may cause nausea.
• Vomiting may occur.
• Diarrhea may occur.
• Skin rash may occur.
• Oral or vaginal yeast overgrowth (thrush) may occur during or after a course.
• Black "hairy" tongue, mouth irritation, or tooth discoloration may occur, particularly in children, and usually improves with brushing or dental cleaning.
• Headache or dizziness may occur.
• Trouble sleeping or agitation may occur.

Serious side effects require immediate discussion with the prescriber or emergency care.

• Serious and occasionally fatal hypersensitivity reactions, including anaphylaxis, can occur.
• Severe skin reactions such as Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis, and drug reaction with eosinophilia and systemic symptoms can occur.
• Kounis syndrome, an allergic reaction that can trigger a heart attack, has been reported.
• Clostridioides difficile-associated diarrhea and colitis can occur, sometimes appearing weeks after finishing treatment.
• Drug-induced enterocolitis syndrome, marked by repeated vomiting and possible progression to shock, has been reported mainly in children.
• Serum sickness-like reactions such as hives, joint swelling, and rash can occur.
• Hepatic dysfunction, including cholestatic jaundice and hepatitis, can occur.
• Blood disorders such as hemolytic anemia, thrombocytopenia, leukopenia, neutropenia, or agranulocytosis can occur.
• Crystalluria with possible acute kidney injury, as well as interstitial nephritis, can occur.
• Aseptic meningitis has been reported, and very high doses can cause seizures or other neurologic effects.
• Seek immediate medical attention for hives, difficulty breathing, facial or throat swelling, chest pain, a widespread rash with blistering or peeling skin, or severe or persistent diarrhea.

• Use cautiously in patients with significant renal impairment, requiring dose adjustment, and in patients with a history of allergy, asthma, hay fever, or urticaria who may have higher hypersensitivity risk.
• Periodic assessment of renal, hepatic, and hematologic function is recommended during prolonged therapy.

• Contraindicated in patients with known hypersensitivity to amoxicillin or any ingredient in the formulation.
• Contraindicated in patients with a history of hypersensitivity reaction to any penicillin.
• Contraindicated in patients with a history of hypersensitivity reaction to any cephalosporin.
• Contraindicated when infectious mononucleosis is suspected or confirmed.

• Methotrexate: amoxicillin can reduce its renal clearance, raising methotrexate levels and increasing toxicity risk.
• Probenecid can raise and prolong amoxicillin blood levels by reducing its renal excretion.
• Warfarin and other oral anticoagulants: amoxicillin can prolong prothrombin time (increased INR), so anticoagulant dosing may need closer monitoring and adjustment.
• Combined oral contraceptives: amoxicillin may reduce their effectiveness by altering gut flora and reducing estrogen reabsorption.
• Tetracyclines: their bacteriostatic action may interfere with amoxicillin's bactericidal effect, so concurrent use is generally avoided.

• May be taken with or without food, though taking it with a full meal can reduce peak absorption somewhat; take with a full glass of water.

• Space doses evenly across the day, such as every 8 hours, to maintain consistent blood levels for the full prescribed course.

• Store capsules, tablets, or unreconstituted granules at room temperature (15 to 30 degrees C); once reconstituted, oral suspension is stable for 14 days at room temperature and should be discarded after that, kept tightly closed.

• Amoxicillin is a penicillin-type antibiotic used to treat bacterial infections such as ear, sinus, throat, urinary tract, skin, and lower respiratory tract infections.
• Take it exactly as prescribed, spaced evenly through the day, and complete the entire course even if you start feeling better after a few days.
• Common side effects include nausea, vomiting, diarrhea, mild rash, headache, and oral or vaginal thrush.
• Call your doctor's office right away if you develop hives, facial or throat swelling, difficulty breathing, a widespread or blistering rash, or severe or persistent diarrhea, since these can signal a serious reaction.
• It can be taken with or without food, though taking it with a meal may help prevent stomach upset; take with a full glass of water.
• Store capsules or tablets at room temperature; if using the liquid suspension, keep it tightly closed and discard any unused portion after 14 days.