Penicillin V Athlone

Phenoxymethylpenicillin.

Each 5 ml of Oral Solution contains 125 mg of Phenoxymethylpenicillin as Phenoxymethylpenicillin Potassium Ph.Eur.
Excipients/Inactive Ingredients: Sodium Benzoate Ph.Eur., Saccharin Sodium Ph.Eur., Trusil Orange Flavour HSE, Orange Colour 175 78 8 HSE, (Containing sunset yellow E110 & Ponceau 4R E124), Sucrose Ph.Eur.

ATC code: J01CE02.
Pharmacology: Pharmacodynamics: In common with other penicillins, phenoxymethypenicillin exerts its killing effects on growing and dividing bacteria by inhibition of bacterial cell wall synthesis. Phenoxymethylpenicillin has a similar range of activity to benzylpenicillin but may be less active against gram negative bacteria.
Phenoxymethylpenicillin is used in the treatment of infections caused by susceptible staphylococci, pneumococci, gonococci, and haemolytic streptococci. Unless very large doses are given, phenoxymethylpenicillin administered by mouth is less effective than parenterally administered benzylpenicillin in the treatment of severe acute infections. It is inactivated by penicillinase.
Pharmacokinetics: Absorption: Rapidly but incompletely absorbed after oral administration (about 60% of an oral dose is absorbed). Calcium and potassium salts are better absorbed than the free acid. Absorption appears to be reduced in patients with coeliac disease. Absorption appears to be more rapid in fasting than non-fasting subjects.
Blood concentration: After an oral dose of 125 mg, peak serum concentrations of 200 to 700 ng/ml are attained in 2 hours. After an oral dose of 500 mg, peak serum concentrations reach 3 to 5 micrograms/ml in 30 to 60 minutes.
Half-life: Biological half-life is about 30 minutes, increased to about 4 hours in severe renal impairment.
Distribution: Widely distributed throughout the body and enters pleural and ascitic fluids and also in cerebrospinal fluid when the meninges are inflamed; Phenoxymethylpenicillin crosses the placenta and is secreted in trace amounts in breast milk; (protein binding 50% to 80% bound plasma proteins).
Metabolic reactions: It is metabolised in the liver; several metabolites have been identified, including penicilloic acid.
Excretion: Unchanged drug and metabolites are excreted rapidly in the urine. (20% to 35% of an oral dose is excreted in the urine in 24 hours).
Toxicology: Pre-clinical Safety Data: Not applicable.

Phenoxymethylpenicillin and phenoxymethylpenicillin potassium are indicated in the treatment of mild to moderately severe infections associated with microorganisms whose susceptibility to penicillin is within the range of serum levels attained with the dosage form.
Note: Severe empyema, bacteraemia, pericarditis, meningitis and arthritis should not be treated with Penicillin V during the acute phase.
The following infections will usually respond to adequate doses: Streptococcal infections (without bacteraemia): Mild to moderate infections of the upper respiratory tract, scarlet fever and mild erysipelas.
Pneumococcal infections: mild to moderately severe infections of the respiratory tract.
Staphylococcal infections sensitive to penicillin: mild infections of the skin and soft tissues.
Fusospirochaetosis (Vincent's gingivitis and pharyngitis): mild to moderately severe infections of the oropharynx usually respond to therapy with oral penicillin.
Prophylactic use: prophylaxis with oral penicillin has proved effective in preventing recurrence of rheumatic fever and chorea.
Patients with a past history of rheumatic fever receiving continuous prophylaxis may harbour penicillin-resistant organisms. In these patients, the use of another prophylactic agent should be considered.
Note: oral penicillin should not be used as adjunctive prophylaxis for genito-urinary instrumentation or surgery, lower intestinal tract surgery, sigmoidoscopy and child birth.

Dosage: Phenoxymethylpenicillin Sugar Free should be given in divided doses (4 times a day) and preferably half an hour before meals or at least three hours after a meal.
The following dosage schedule applies to Phenoxymethylpenicillin Sugar Free: (See table.)

Click on icon to see table/diagram/image

RENAL IMPAIRMENT: Reduce dose if renal function is markedly impaired.
In patients with beta-haemolytic streptococcal infection, it is usual to continue treatment at the full dosage for 10 days, in order to minimise the occurrence of secondary complications such as acute nephritis and rheumatic fever.
For oral administration only.

Signs and Symptoms: A large oral overdose of penicillin may cause 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 from overdosage, particularly for patients with renal insufficiency.
Treatment: No specific antidote is known. Symptomatic and supportive therapy is recommended. Activated charcoal with a cathartic, such as sorbitol may hasten drug elimination. Penicillin may be removed by haemodialysis.

Phenoxymethylpenicillin is contraindicated in patients known to be hypersensitive to Penicillin and should be used with caution in patients with known histories of allergy.
Sucrose: Patients with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency should not take this medicine.

Penicillin should be used with caution in individuals with histories of significant allergies and/or asthma. All degrees of hypersensitivity, including fatal anaphylaxis, have been observed with oral penicillin. These reactions are more likely to occur in individuals with a history of sensitivity to penicillins, cephalosporins and other allergens. Enquiries should be made for such a history before therapy is begun. If any allergic reaction occurs, the drug should be discontinued and the patient treated with the usual agents (e.g. adrenaline and other pressor amines, antihistamines and corticosteroids).
Oral therapy should not be relied upon for patients with severe illness, or with nausea, vomiting, gastric dilation, achalasia or intestinal hypermotility. Occasionally patients do not absorb therapeutic amounts of orally administered penicillin.
Administer with caution in the presence of markedly impaired renal function, as safe dosage may be lower than the usually recommended doses.
Streptococcal infections should be treated for a minimum of 10 days, and post therapy cultures should be performed to confirm the eradication of the organisms.
Prolonged use of antibiotics may promote the over growth of non-susceptible organisms, including fungi. If super infection occurs, appropriate measures should be taken.
Effects on Ability to Drive and Use Machines: None known.

Pregnancy: Although laboratory and clinical studies have shown no evidence of teratogenicity, caution should be exercised when prescribing to the pregnant patient.
Lactation: Phenoxymethylpenicillin is excreted in trace amounts in breast milk, presenting a risk of allergic reaction in the infant.

The most common reactions to oral penicillin are gastrointestinal effects and hypersensitivity reactions. Although hypersensitivity reactions have been reported much less frequently after oral than after parenteral therapy, it should be remembered that all forms of hypersensitivity, including fatal anaphylaxis have been observed with oral penicillin.
Blood and lymphatic disorders: There have been very rare reports of changes in blood counts, including, thrombocytopenia, neutropenia, leucopenia, eosinophilia and haemolytic anaemia. Coagulation disorders (including prolongation of bleeding time and defective platelet function) have also been reported.
Gastrointestinal disorders: Nausea, vomiting, abdominal pain, diarrhoea are common. Sore mouth and black hairy tongue (discolouration of tongue) has been reported occasionally.
Hepatobiliary disorders: Hepatitis and cholestatic jaundice have been reported very rarely.
Immune disorders: Allergic reactions may commonly occur and typically manifest as skin reactions (see Skin and subcutaneous disorders). Severe allergic reactions causing angioedema, laryngeal oedema and anaphylaxis have been reported rarely.
Serum sickness-like reactions are characterised by fever, chills, arthralgia and oedema.
Infections and infestations: Pseudomembranous colitis has occasionally been reported.
Nervous system disorders: Central nervous system toxicity including convulsions has been reported (especially with high doses or in severe renal impairment); paraesthesia may occur with prolonged use.
Neuropathy is an infrequent reaction and is usually associated with high doses of parenteral penicillin.
Renal and urinary disorders: Interstitial nephritis has occurred in very rare cases.
Nephropathy is an infrequent reaction and is usually associated with high doses of parenteral penicillin.
Skin and subcutaneous disorders: Urticarial, erythematous or mobilliform rash and pruritus occur most frequently, while exfoliative dermatitis occurs rarely.

Aminoglycosides: Neomycin is reported to reduce the absorption of phenoxymethylpenicillin.
Anticoagulants: Penicillins may interfere with anticoagulant control.
Bacteriostatic antibiotics: Certain bacteriostatic antibiotics such as Chloramphenicol, Erythromycin and Tetracyclines have been reported to antagonise the bactericidal activity of penicillins and concomitant use is not recommended.
Guar gum: Reduced absorption of phenoxymethylpenicillin.
Methotrexate: Use of Phenoxymethylpenicillin while taking methotrexate can cause reduced excretion of methotrexate thereby increasing the risk of toxicity.
Oral Contraceptives: Penicillin may reduce the efficacy of combined oral contraceptives.
Probenecid: Reduced excretion of phenoxymethylpenicillin by competing with it for renal tubular secretion.
Sulfinpyrazone: Excretion of penicillins reduced by sulfinpyrazone.
Typhoid vaccine (oral): Penicillins may inactivate oral typhoid vaccine if ingested concomitantly.

Instructions for Use, Handling and Disposal: No special instructions.
Incompatibilities: None known.

Unconstituted powder: Store in a dry place below 25°C. Protect from light.
Reconstituted oral solution: Store for 7 days in a refrigerator.
Shelf-Life: Unopened container: 24 months.
Reconstituted oral solution: a shelf life of 7 days.

Penicillins

J01CE02 - phenoxymethylpenicillin ; Belongs to the class of beta-lactamase sensitive penicillins. Used in the systemic treatment of infections.

A

Tab 250 mg x 1000's. Elixir (powd for oral soln) 125 mg/5 mL x 100 mL.