Amoxy

# Amoxy (Amoxicillin) ## Overview - **Classification**: Beta-lactam antibiotic, aminopenicillin class. - **Mechanism**: Inhibits bacterial cell wall mucopeptide synthesis by binding to penicillin-binding proteins (PBPs), leading to bacterial cell lysis and death. ## Primary Indications 1. **Acute Otitis Media (AOM)** - Bacterial middle ear infection. 2. **Streptococcal Pharyngitis** - "Strep throat" caused by Group A Streptococcus. 3. **Sinusitis** - Bacterial infection of the sinuses. 4. **Lower Respiratory Tract Infections** - E.g., community-acquired pneumonia. 5. **H. pylori Eradication** - As part of a multi-drug regimen for gastric ulcers. ## Adult Dosing ### Standard Dosing **Mild to Moderate Infections (e.g., Sinusitis, AOM, Bronchitis)** - **Dose**: **500 mg** - **Frequency**: Every 8 hours (TID) - **Route**: Oral - **Duration**: 7-10 days **Severe Infections (e.g., Severe AOM, Lower Respiratory Tract Infections)** - **Dose**: **875 mg** - **Frequency**: Every 12 hours (BID) - **Route**: Oral - **Duration**: 7-10 days **H. pylori Eradication** (as part of a multi-drug regimen) - **Dose**: **1000 mg** - **Frequency**: Every 12 hours (BID) - **Route**: Oral - **Duration**: 7-14 days ### Dose Adjustments - **Renal Impairment**: - CrCl 10-30 mL/min: **250-500 mg** every 12 hours. - CrCl <10 mL/min: **250-500 mg** every 24 hours. - Hemodialysis: **250-500 mg** every 24 hours, with an additional dose during/after dialysis. - **Hepatic Impairment**: No specific adjustment needed. - **Elderly Patients**: Adjust dose based on estimated renal function. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: **20-30 mg/kg/day** divided - **Frequency**: Every 12 hours - **Maximum**: **50 mg/kg/day** (consider for severe infections, but dose cautiously). - **Special Notes**: Use cautiously due to immature renal function. Dosing intervals may need to be extended. ### Infants (1-12 months) - **Mild-Moderate Infections**: - **Dose**: **25 mg/kg/day** divided - **Frequency**: Every 12 hours - **Maximum**: **250 mg/dose** - **Severe Infections (e.g., High-dose AOM)**: - **Dose**: **45 mg/kg/day** divided - **Frequency**: Every 12 hours - **Maximum**: **500 mg/dose** ### Children (1-12 years) - **Mild-Moderate Infections**: - **Dose**: **25 mg/kg/day** divided - **Frequency**: Every 12 hours - **Maximum**: **500 mg/dose** or **1000 mg/day**. - **Severe Infections (e.g., High-dose AOM, Sinusitis)**: - **Dose**: **40-45 mg/kg/day** divided (up to **90 mg/kg/day** for AOM) - **Frequency**: Every 12 hours - **Maximum**: **875 mg/dose** or **1750 mg/day**. ### Adolescents (13-18 years) - **Dose**: Follow **adult dosing** guidelines. - **Maximum**: **1750 mg/day** (standard) up to **3000 mg/day** for specific severe infections. ## Safety Information ### Contraindications - **Absolute**: History of severe hypersensitivity reaction to any penicillin (e.g., anaphylaxis, Stevens-Johnson Syndrome). - **Relative**: History of infectious mononucleosis (high risk of maculopapular rash). ### Common Adverse Effects - **Common (1-10%)**: Nausea, vomiting, diarrhea, rash (maculopapular), candidiasis. - **Serious but Rare**: Anaphylaxis, Clostridioides difficile-associated diarrhea (CDAD), Stevens-Johnson syndrome (SJS), interstitial nephritis, hemolytic anemia. ### Key Drug Interactions - **Warfarin**: May increase INR. Monitor INR closely, especially when initiating/discontinuing amoxicillin. - **Methotrexate**: May decrease methotrexate clearance, increasing toxicity. Monitor methotrexate levels. - **Allopurinol**: Increases risk of amoxicillin-induced skin rash. Avoid co-administration if possible. - **Oral Contraceptives**: May reduce efficacy. Advise backup contraception. ## Monitoring & Follow-up - **Before Treatment**: Assess for any history of penicillin allergy. - **During Treatment**: Monitor for signs of allergic reaction (rash, itching, dyspnea). - **During Treatment**: Assess for resolution of infection symptoms. - **Clinical Signs**: Worsening diarrhea or abdominal pain (CDAD), new or severe rash, signs of anaphylaxis. ## Clinical Pearls - 💡 **Suspension formulations** require shaking well before each dose. - 💡 Can be taken with or without food. Taking with food may reduce GI upset. - 💡 Complete the full course of therapy, even if symptoms improve, to prevent antibiotic resistance. - 💡 A non-allergic maculopapular rash is common in patients with mononucleosis treated with amoxicillin; it is not a true penicillin allergy. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.