Amoxicillin Dosing and Counseling for Acute Otitis Media
Ms. R brings her 3-year-old son, Noah, to the community pharmacy with a new prescription for amoxicillin suspension 250 mg/5 mL. Noah weighs 14 kg and has acute otitis media with fever 39.1°C and right ear pain. The prescription reads: amoxicillin 90 mg/kg/day PO divided BID for 10 days. Noah had amoxicillin six months ago for otitis media without rash or other reaction. He attends daycare and has no vomiting. His mother has a kitchen teaspoon at home and asks whether that is fine for measuring. She also wants to know if the dose is correct because the last prescription was different. The pharmacy is busy, and the mother is anxious to get home. She mentions Noah had a mild rash after a viral illness last year, but no known drug allergies.
1. Calculate the prescribed dose and volume per administration. Is the dose appropriate?
Read the worked answer
- Daily dose: 90 mg/kg/day × 14 kg = 1260 mg/day.
- Divided BID: 630 mg per dose.
- Suspension concentration: 250 mg/5 mL = 50 mg/mL.
- Volume per dose: 630 mg ÷ 50 mg/mL = 12.6 mL.
- The dose is appropriate for high-dose amoxicillin therapy for acute otitis media. The daily total (1260 mg) is below the usual maximum (often 2 g/day in children, depending on local protocol).
- Because amoxicillin was last used six months ago, not within the past 30 days, amoxicillin remains a reasonable first-line choice.
2. What counseling points will you provide about measuring, administration, and side effects?
Read the worked answer
- Measuring: dispense an oral syringe and show the mother how to draw up 12.6 mL (or the nearest marked volume, such as 12.5 mL). A kitchen teaspoon is not accurate.
- Administration: shake well; give with food if GI upset; complete the 10-day course even if the child improves.
- Storage: refrigerate the suspension and discard after 14 days or per label.
- Side effects: diarrhea, nausea, and rash are possible. Probiotics are not routinely required but can be discussed.
- Return precautions: no improvement in 48–72 hours, persistent vomiting, decreased urine output, severe diarrhea, or any breathing difficulty.
- Rash history: clarify that the prior rash was after a viral illness, not a drug reaction; document no known drug allergy.
3. The mother calls two days later because Noah developed a rash. How do you assess and advise?
Read the worked answer
- Ask about red flags: urticaria, facial or lip swelling, difficulty breathing, mucosal ulcers, fever, skin peeling, or blistering.
- If urticaria, angioedema, or systemic symptoms are present: stop amoxicillin and arrange urgent medical assessment.
- If the rash is a mild maculopapular eruption and the child is otherwise well, it may be viral or a benign amoxicillin-associated rash. The child can often continue the antibiotic with monitoring, but this depends on the clinical picture.
- Do not label a drug allergy without clear evidence; document the description and advise the mother to report any progression.
- If uncertain, contact the prescriber.