Formulary
Phenoxymethylpenicillin: Indications, Dosing, Side Effects and Interactions
The penicillins are bactericidal and act by interfering with bacterial cell wall synthesis.
MedNext Academy | 4 min read
Phenoxymethylpenicillin: Indications, Dosing, Side Effects and Interactions
The penicillins are bactericidal and act by interfering with bacterial cell wall synthesis.
Drug action
The penicillins are bactericidal and act by interfering with bacterial cell wall synthesis. They diffuse well into body tissues and fluids, but penetration into the cerebrospinal fluid is poor except when the meninges are inflamed. They are excreted in the urine in therapeutic concentrations.
Indications and dose
**Oral infections,Otitis media**
- **Child** (By Mouth): 12-17 years 500 mg 4 times a day, increased if necessary up to 1 g 4 times a day.
- **Adult** (By Mouth): 500 mg every 6 hours, increased if necessary up to 1 g every 6 hours.
**Acute sore throat**
- **Child** (By Mouth): 12-17 years 500 mg 4 times a day for 5-10 days, alternatively 1000 mg twice daily for 5-10 days.
- **Adult** (By Mouth): 500 mg 4 times a day for 5-10 days, alternatively 1000 mg twice daily for 5-10 days.
**Prevention of recurrent cellulitis (specialist use only),Prevention of recurrent erysipelas (specialist use only)**
- **Adult** (By Mouth): 250 mg twice daily.
**Prevention of recurrence of rheumatic fever**
- **Child** (By Mouth): 6-17 years 250 mg twice daily.
- **Adult** (By Mouth): 250 mg twice daily.
**Prevention of secondary case of invasive group A streptococcal infection**
- **Child** (By Mouth): 12-17 years 250-500 mg every 6 hours for 10 days.
- **Adult** (By Mouth): 250-500 mg every 6 hours for 10 days.
**Prevention of pneumococcal infection in asplenia or in patients with sickle-cell disease**
- **Child** (By Mouth): 5-17 years 250 mg twice daily.
- **Adult** (By Mouth): 250 mg twice daily.
**Acute sinusitis**
- **Child** (By Mouth): 12-17 years 500 mg 4 times a day for 5 days.
- **Adult** (By Mouth): 500 mg 4 times a day for 5 days.
**Oral infections, Otitis media for phenoxymethylpenicillin**
- **Child 1-11 months** (By mouth): 62.5 mg 4 times a day, increased if necessary up to 12.5 mg/kg 4 times a day.
- **Child 1-5 years** (By mouth): 125 mg 4 times a day, increased if necessary up to 12.5 mg/kg 4 times a day.
- **Child 6-11 years** (By mouth): 250 mg 4 times a day, increased if necessary up to 12.5 mg/kg 4 times a day.
- **Child 12-17 years** (By mouth): 500 mg 4 times a day, increased if necessary up to 1 g 4 times a day.
**Acute sore throat for phenoxymethylpenicillin**
- **Child 1-11 months** (By mouth): 62.5 mg 4 times a day for 5-10 days, alternatively 125 mg twice daily for 5-10 days.
- **Child 1-5 years** (By mouth): 125 mg 4 times a day for 5-10 days, alternatively 250 mg twice daily for 5-10 days.
- **Child 6-11 years** (By mouth): 250 mg 4 times a day for 5-10 days, alternatively 500 mg twice daily for 5-10 days.
- **Child 12-17 years** (By mouth): 500 mg 4 times a day for 5-10 days, alternatively 1000 mg twice daily for 5-10 days.
**Prevention of recurrence of rheumatic fever for phenoxymethylpenicillin**
- **Child 1 month-5 years** (By mouth): 125 mg twice daily.
- **Child 6-17 years** (By mouth): 250 mg twice daily.
**Prevention of secondary case of invasive group A streptococcal infection for phenoxymethylpenicillin**
- **Neonate** (By mouth): 12.5 mg/kg every 6 hours (max. per dose 62.5 mg) for 10 days.
- **Child 1-11 months** (By mouth): 62.5 mg every 6 hours for 10 days.
- **Child 1-5 years** (By mouth): 125 mg every 6 hours for 10 days.
- **Child 6-11 years** (By mouth): 250 mg every 6 hours for 10 days.
- **Child 12-17 years** (By mouth): 250-500 mg every 6 hours for 10 days.
**Prevention of pneumococcal infection in asplenia or in patients with sickle-cell disease for phenoxymethylpenicillin**
- **Child 1-11 months** (By mouth): 62.5 mg twice daily.
- **Child 1-4 years** (By mouth): 125 mg twice daily.
- **Child 5-17 years** (By mouth): 250 mg twice daily.
**Acute sinusitis for phenoxymethylpenicillin**
- **Child 1-11 months** (By mouth): 62.5 mg 4 times a day for 5 days.
- **Child 1-5 years** (By mouth): 125 mg 4 times a day for 5 days.
- **Child 6-11 years** (By mouth): 250 mg 4 times a day for 5 days.
- **Child 12-17 years** (By mouth): 500 mg 4 times a day for 5 days.
Cautions
History of allergy
Side effects
Common or very common Diarrhoea; hypersensitivity; nausea; skin reactions; thrombocytopenia; vomiting Uncommon Arthralgia; leucopenia Rare or very rare Agranulocytosis; angioedema; haemolytic anaemia; hepatic disorders; nephritis tubulointerstitial; neutropenia; pseudomembranous enterocolitis; seizure; severe cutaneous adverse reactions (SCARs) Side-effects, further information Diarrhoea frequently occurs during oral penicillin therapy. It is most common with broad-spectrum penicillins, which can cause antibiotic-associated colitis. Side-effects For phenoxymethylpenicillin Frequency not known Circulatory collapse; coagulation disorder; eosinophilia; faeces soft; fever; increased risk of infection; neurotoxicity; oral disorders; paraesthesia
Pregnancy
Not known to be harmful.
Breast feeding
Trace amounts in milk, but appropriate to use.
Medicinal forms
Tablet,Solution
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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