Phenoxymethylpenicillin

Oral
Erysipelas, Scarlet fever, Streptococcal infections of the upper respiratory tract

Oral
Fusospirochetosis (Vincent's infection) of the oropharynx, Staphylococcal infections of the skin and soft tissue

Oral
Pneumococcal infections of the respiratory tract, including otitis media

Oral
Prophylaxis of recurrent rheumatic fever

Oral
Susceptible infections

Dose adjustment may be necessary.

Should be taken on an empty stomach. Take 1 hr before or 2 hr after meals.

Powd for oral soln: Add the amount of water specified on the bottle to provide a soln containing 125 mg or 250 mg per 5 mL. The water should be added to the powd in 2 portions and the soln agitated vigorously immediately after each addition.

Hypersensitivity to to phenoxymethylpenicillin and other penicillins. Concomitant use w/ nadolol and propranolol.

Patient w/ history of asthma, seizure disorders, history of β-lactam allergy. Severe renal impairment. Pregnancy and lactation.

Nausea, vomiting, abdominal pain, diarrhoea, sore mouth, black hairy tongue, thrombocytopenia, neutropenia, leucopenia, eosinophilia, haemolytic anaemia, coagulation disorders, hepatitis, cholestatic jaundice, allergic reactions, serum sickness-like reactions, convulsions, paraesthesia, neuropathy, interstitial nephritis, nephropathy, urticaria, rash, pruritus.
Potentially Fatal: Anaphylaxis, pseudomembranous colitis.

PO: B

Monitor renal and haematologic functions, signs of anaphylaxis during 1st dose.

Symptoms: Nausea, vomiting, stomach pain, diarrhoea, and rarely, major motor seizures. If other symptoms are present, consider the possibility of an allergic reaction. Hyperkalaemia may result, particularly for patients w/ renal insufficiency. Management: Symptomatic and supportive treatment. May admin activated charcoal w/ a cathartic, e.g. sorbitol to hasten drug elimination. May be removed by haemodialysis.

Reduced absorption w/ neomycin. May interfere w/ anticoagulant control. Antagonism of bactericidal effect by chloramphenicol, erythromycin and tetracyclines. May increase toxicity of methotrexate. May reduce the efficacy of OC. Reduced excretion w/ probenecid and sulfinpyrazone. May inactivate oral typhoid vaccine if ingested concomitantly.
Potentially Fatal: Increased risk of anaphylactic reactions w/ nadolol and propranolol.

Absorption may be slightly affected by food.

False-positive urine glucose reactions w/ Clinitest, Benedict soln, or Fehling soln. Positive Coombs test.

Description: Phenoxymethylpenicillin inhibits the final cross-linking stage of peptidoglycan production through binding and inactivation of transpeptidases on the inner surface of the bacterial cell membrane, thus inhibiting bacterial cell wall synthesis. It may be less active against some susceptible organisms, particularly gm-ve bacteria. It is suitable for mild to moderate infections.
Pharmacokinetics:
Absorption: Rapidly but incompletely absorbed (approx 60%) from the GI tract. Absorption is slightly affected by the presence of food. Bioavailability: Approx 60%. Time to peak plasma concentrations: 30-60 min.
Distribution: Widely distributed into body tissues. Crosses the placenta and enters breast milk. Plasma protein binding: Approx 80%.
Metabolism: Undergoes hepatic metabolism. Several metabolites have been identified, including penicilloic acid.
Excretion: Via urine (as unchanged drug and metabolites) and bile (small amounts). Plasma half-life: Approx 30-60 min.

Source: National Center for Biotechnology Information. PubChem Database. Penicillin v, CID=6869, https://pubchem.ncbi.nlm.nih.gov/compound/Penicillin-v (accessed on Jan. 22, 2020)

Tab/powd for oral soln: Store between 20-25°C. Reconstituted oral soln: Store between 2-8°C. Protect from light.

Penicillins

Anon. Penicillin V Potassium (Oral). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 25/06/2014.

Buckingham R (ed). Phenoxymethylpenicillin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 25/06/2014.

McEvoy GK, Snow EK, Miller J et al (eds). Penicillin V, Penicillin V Potassium. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 25/06/2014.

Penicillin V Potassium Tablet (Sandoz Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 25/06/2014.

Wickersham RM. Penicillin V Potassium. Facts and Comparisons [online]. St. Louis, MO. Wolters Kluwer Clinical Drug Information, Inc. https://www.wolterskluwercdi.com/facts-comparisons-online/. Accessed 25/06/2014.