PENICILLIN V POTASSIUM
For general information on the penicillins, including adverse effects, contraindications, overdosage, drug interactions and monitoring parameters, refer to the monograph: Penicillins, General Information.
Chemistry - A natural penicillin, penicillin V is produced from Penicillium chrysogenum and isusually commercially available as the potassium salt. It may also be known as phenoxymethylpenicillin potassium. Penicillin V potassium occurs as an odorless, white, crystallinepowder that is very soluble in water and slightly soluble in alcohol. Potency of penicillin Vpotassium is usually expressed in terms of weight (in mg) of penicillin V, but penicillin V units mayalso be used. One mg of penicillin V potassium is equivalent to 1380-1610 USP Units of penicillin
V. Manufacturers, however, generally state that 125 mg of penicillin V potassium is approximatelyequivalent to 200, 000 USP units of penicillin V.
Pharmacology, Uses, Indications - Penicillin V may be slightly less active than penicillin Gagainst organisms susceptible to the natural penicillins, but its superior absorptive characteristicsafter oral administration make it a better choice against mild to moderately severe infections whenoral administration is desired in monogastric animals. For more information on the types oforganisms that penicillin V generally covers, refer to the general statement on penicillins and thepenicillin G monograph.
Pharmacokinetics (specific) - The pharmacokinetics of penicillin V are very similar to penicillin
G with the exception of oral bioavailability and the percent of the drug that is bound to plasmaproteins. Penicillin V is significantly more resistant to acid-catalyzed inactivation in the gut andbioavailability after oral administration in humans is approximately 60-73%. In veterinary species, actual bioavailability measurements have been measured in calves (30%), but studies performed inhorses and dogs have demonstrated that therapeutic serum levels can be achieved with the drug afteroral administration. In dogs, it has been shown that food will decrease the rate and extent ofabsorption of the drug from the gut.
Distribution of penicillin V follows that of penicillin G but, at least in humans, the drug is boundto a larger extent to plasma proteins (approximately 80% with penicillin VK vs. 50% with penicillin
G).
Like penicillin G, penicillin V is excreted rapidly in the urine via the kidney. Elimination half-livesare generally less than 1 hour in animals with normal renal function, but an elimination half-life of3.65 hours has been reported after oral dosing in horses (Schwark et al. 1983).
Chemistry - A natural penicillin, penicillin V is produced from Penicillium chrysogenum and isusually commercially available as the potassium salt. It may also be known as phenoxymethylpenicillin potassium. Penicillin V potassium occurs as an odorless, white, crystallinepowder that is very soluble in water and slightly soluble in alcohol. Potency of penicillin Vpotassium is usually expressed in terms of weight (in mg) of penicillin V, but penicillin V units mayalso be used. One mg of penicillin V potassium is equivalent to 1380-1610 USP Units of penicillin
V. Manufacturers, however, generally state that 125 mg of penicillin V potassium is approximatelyequivalent to 200, 000 USP units of penicillin V.
Storage, Stability, Compatibility
Penicillin V potassium tablets and powder for oral solutionshould be stored in tight containers at room temperature (15-30°C). After reconstitution, the oralsolution should be stored at 2-8°C (refrigerated) and any unused portion discarded after 14 days.Pharmacology, Uses, Indications - Penicillin V may be slightly less active than penicillin Gagainst organisms susceptible to the natural penicillins, but its superior absorptive characteristicsafter oral administration make it a better choice against mild to moderately severe infections whenoral administration is desired in monogastric animals. For more information on the types oforganisms that penicillin V generally covers, refer to the general statement on penicillins and thepenicillin G monograph.
Pharmacokinetics (specific) - The pharmacokinetics of penicillin V are very similar to penicillin
G with the exception of oral bioavailability and the percent of the drug that is bound to plasmaproteins. Penicillin V is significantly more resistant to acid-catalyzed inactivation in the gut andbioavailability after oral administration in humans is approximately 60-73%. In veterinary species, actual bioavailability measurements have been measured in calves (30%), but studies performed inhorses and dogs have demonstrated that therapeutic serum levels can be achieved with the drug afteroral administration. In dogs, it has been shown that food will decrease the rate and extent ofabsorption of the drug from the gut.
Distribution of penicillin V follows that of penicillin G but, at least in humans, the drug is boundto a larger extent to plasma proteins (approximately 80% with penicillin VK vs. 50% with penicillin
G).
Like penicillin G, penicillin V is excreted rapidly in the urine via the kidney. Elimination half-livesare generally less than 1 hour in animals with normal renal function, but an elimination half-life of3.65 hours has been reported after oral dosing in horses (Schwark et al. 1983).