Phenoxymethylpenicillin Potassium

Synonyms: Fenoksimetil Penisilin Potasyum; Fenoksimetilpenicilino kalio druska; Fenoksimetyylipenisilliinikalium; Fenoksymetylopenicylina potasowa; Fenoximetilpenicilina potásica; Fenoximetilpenicilina Potássica; Fenoximetilpenicillin-kálium; Fenoximetylpenicillin kalium; Fenoxymethylpenicilin draselná sůl; Kalii Phenoxymethylpenicillinum; Penicillin V Potassium line potassique; Phenoxymethylpenicillinum kalicum.
Cyrillic synonym: Калия Феноксиметилпенициллин.

💊 Chemical information

Chemical formula: C16H17KN2O5S = 388.5.
CAS — 132-98-9.
ATC — J01CE02.
ATC Vet — QJ01CE02.


In Chin., Eur., Int., US, and Viet.

Ph. Eur. 6.2

(Phenoxymethylpenicillin Potassium). A white or almost white, crystalline powder. Freely soluble in water; practically insoluble in alcohol. A 0.5% solution in water has a pH of 5.5 to 7.5.

USP 31

(Penicillin V Potassium). A white, odourless crystalline powder. Very soluble in water; soluble 1 in 150 of alcohol; insoluble in acetone. pH of a 3% solution in water is between 4.0 and 7.5. Store in airtight containers.

💊 Units

The first International Standard Preparation (1957) of phenoxymethylpenicillin contained 1695 units/mg but was withdrawn in 1968. Despite this, doses of phenoxymethylpenicillin are still expressed in units in some countries. Phenoxymethylpenicillin 250 mg is equivalent to about 400 000 units.

💊 Adverse Effects and Precautions

As for Benzylpenicillin. Phenoxymethylpenicillin is usually well tolerated but may occasionally cause transient nausea and diarrhoea.

Potassium content.

Each g of phenoxymethylpenicillin potassium contains about 2.6 mmol of potassium.

💊 Interactions


Reduced absorption was reported when phenoxymethylpenicillin was given after an oral course of neomycin.1
1. Cheng SH, White A. Effect of orally administered neomycin on the absorption of penicillin V. N Engl J Med 1962; 267: 1296–7.

Beta blockers.

Fatal anaphylactic reactions to phenoxymethylpenicillin in 2 patients on nadolol and propranolol respectively, might have been potentiated by the beta blocker.1
1. Berkelman RL, et al. Beta-adrenergic antagonists and fatal anaphylactic reactions to oral penicillin. Ann Intern Med 1986; 104: 134.

💊 Antimicrobial Action

Phenoxymethylpenicillin has a range of antimicrobial activity similar to that of benzylpenicillin and a similar mode of action. It may be less active against some susceptible organisms, particularly Gram-negative bacteria. The mechanisms and patterns of resistance to phenoxymethylpenicillin are similar to those of benzylpenicillin.

💊 Pharmacokinetics

Phenoxymethylpenicillin is more resistant to inactivation by gastric acid and is more completely absorbed than benzylpenicillin from the gastrointestinal tract. Absorption is usually rapid, although variable, with about 60% of an oral dose being absorbed. The calcium and potassium salts are better absorbed than the free acid. Peak plasma concentrations of 3 to 5 micrograms/mL have been observed 30 to 60 minutes after a dose of 500 mg. The effect of food on absorption appears to be slight. The plasma half-life of phenoxymethylpenicillin is about 30 to 60 minutes and may be increased to about 4 hours in severe renal impairment. About 80% is reported to be protein bound. The distribution and elimination of phenoxymethylpenicillin is similar to that of benzylpenicillin. It is metabolised in the liver to a greater extent than benzylpenicillin; several metabolites have been identified including penicilloic acid. The unchanged drug and metabolites are excreted rapidly in the urine. Only small amounts are excreted in the bile.

💊 Uses and Administration

Phenoxymethylpenicillin is used similarly to benzylpenicillin in the treatment or prophylaxis of infections caused by susceptible organisms, especially streptococci. It is used only for the treatment of mild to moderate infections, and not for chronic, severe, or deep-seated infections since absorption can be unpredictable. Patients treated initially with parenteral benzylpenicillin may continue treatment with oral phenoxymethylpenicillin once a satisfactory clinical response has been obtained. Specific indications for phenoxymethylpenicillin include anthrax (mild uncomplicated infections), Lyme disease (early stage in pregnant women or young children), pharyngitis or tonsillitis, rheumatic fever (primary and secondary prophylaxis), streptococcal skin infections, and spleen disorders is also used. Doses are expressed in terms of the equivalent amount of phenoxymethylpenicillin; 1.1 g of phenoxymethylpenicillin calcium and 1.1 g of phenoxymethylpenicillin potassium are each equivalent to about 1 g of phenoxymethylpenicillin. Usual adult doses have been 250 to 500 mg every 6 hours, but the BNF recommends up to 1 g every 6 hours in severe infections. Children may be given the following doses every 6 hours: up to 1 year, 62.5 mg; 1 to 5 years, 125 mg; and 6 to 12 years, 250 mg. The BNFC recommends that doses be increased to ensure at least 12.5 mg/kg every 6 hours in severe infection. Dosage may need to be modified in severe renal impairment. To prevent recurrences of rheumatic fever, WHO and
the BNF recommend 250 mg twice daily.

💊 Preparations

BP 2008: Phenoxymethylpenicillin Oral Solution; Phenoxymethylpenicillin Ta b l e t s ; USP 31: Penicillin V for Oral Suspension; Penicillin V Potassium for Oral Solution; Penicillin V Potassium Tablets; Penicillin V Tablets.

Proprietary Preparations

Arg.: Pen Oral; Penagrand; Penfantil; Penicina; Austral.: Abbocillin-VK; Cilicaine VK; Cilopen VK; LPV; Penhexal VK; Austria: Aliucillin; Cliacil; Megacillin; Ospen; Pen-V; Penbene; Penoral; Penstad; Star-Pen; Belg.: Peni-Oral; Braz.: Meracilina; Oracilin; Pen-V-Cil; Pen-Ve-Oral; Pencilin-V; Penicigran; Canad.: Apo-Pen-VK; Nadopen-V†; Novo-Pen-VK; Nu-Pen-VK; Pen-Vee†; PVFK†; Cz.: InfectoCillin†; Megacillin†; Ospen; Penbene; Pencid; Denm.: Calcipen; Pancillin; Primcillin; Rocilin; Vepicombin; Fin.: Medicillin; Milcopen; V- Pe n; Fr.: Oracilline; Ospen†; Ger.: Arcasin; durapenicillin†; InfectoCillin; Isocillin; Ispenoral; Jenacillin V†; Megacillin oral; P-Mega-Tablinen; Pen Mega; Pen†; Penbeta; Penhexal; Penicillat†; V-Tablopen†; Gr.: Ospen; Hong Kong: Ospen†; Hung.: Ospen; Vegacillin†; Indon.: Fenocin; Ospen; Irl.: Calvepen; Kopen; Israel: Rafapen Mega; Rafapen V-K; Malaysia: Beapen; Ospen; Penoxil V†; Mex.: Anapenil; Kavipen; Megapenil†; Pen-Vi-K; PotaVi-Kin; Neth.: Acipen; Acipen-V; Norw.: Apocillin; Calcipen†; Kavepenin†; Rocilin†; Weifapenin; NZ: Cilicaine VK; Philipp.: Sumapen; Pol.: Ospen; Rus.: Ospen (Оспен); S.Afr.: Betapen; Deltacillin†; Incil; Len V.K.; Novo VK†; Rolab-Pen-V-K†; Spec-Pen-V-K; Singapore: Ospen; Spain: Penilevel; Swed.: Kavepenin; Peceve; Tikacillin; Switz.: Brunocillin†; Megacilline†; Ospen; pen-V-basan†; Penisol; Phenocillin; Stabicilline; Thai.: Pen-V; Pener ; Penveno; Servipen-V†; Turk.: Cilacil; USA: Pen-Vee K; Veetids; Venez.: Ospen. Multi-ingredient: Spain: Penilevel Retard.
Published May 08, 2019.