Penicillins Procaine benzylpenicillin

Pen (Wyeth-Ayerst)-(penicillin V potassium) Pfizerpen G (Pfizer)-(penicillin G potassium) Sugracillin (Upjohn) Wycillin (Wyeth-Ayerst)-(procaine-benzylpenicillin)... 

Synonyms. Benzylpenicillin Novocaine Penicillin G Procaine Procaine Benzylpenicillin Procaine Penicillin G. 

Elimination of the penicillins is primarily via the kidneys, by glomerular filtration and active tubular secretion. The half-life is approximately 1 h after i.v. injection. Because of slow absorption from the injection site, the half-life of procaine benzylpenicillin (procaine penicillin) is approximately 7h. 

Adverse CNS effects occur when the procaine portion of the procaine benzylpenicillin (procaine penicillin) formulation is given intravascularly. The signs of toxicity include hyperexcitability, muscle tremors, ataxia, apnea and cardiac arrest. There is no specific treatment for procaine toxicity one can only attempt to prevent the horse from injuring itself and others imtil the effects of the procaine wear off. The CNS reaction can be prevented by pretreatment with diazepam. The solubility of the procaine fraction of procaine benzylpenicillin (procaine penicillin) formulations increases with increasing ambient temperature, so these products should be stored in a cool place to reduce the risk of reactions. Procaine is a common cause of positive drug tests in racehorses and other performance horses. Procaine benzylpenicillin (procaine penicillin) should be avoided in these animals. 

Procaine benzylpenicillin (procaine penicillin) is a poorly soluble salt that is absorbed slowly following i.m. or s.c. injection. It is the most commonly used formulation of penicillin in horses. Injections s.c. cause severe local inflammation and hemorrhage, as well as leaving deposits of... 

Benzathine benzylpenicillin is a very insoluble salt. It is administered i.m. in "long-acting" formulations that contain one-half procaine benzylpenicillin (procaine penicillin) and one-half benzathine benzylpenicillin. Any clinical effect is from the procaine benzylpenicillin (procaine penicillin) portion of these formulations since the benzathine penicillin provides persistent but sub-therapeutic plasma concentrations. 

Penicillin G, benzathine and procaine (benzylpenicillin, benzathine and procaine) 9000 -16 80Qt U/kg, every 48-96 h i.m. 

Penicillin G, procaine (benzylpenicillin, procaine) 6600 -16000 U/kg, once daily i.m. 

A study in patients given intramuscular procaine benzylpenicillin 2.4 or 4.8 million units with or without probenecid 2 g found the peak serum levels were higher in patients given probenecid, but because of wide interpatient variation, possibly associated with differences in the release of penicillin from the injection sites, the exact potentiating effect of probenecid could not be determined. However, another study in men and women given procaine benzylpenicillin 2.4 million units and 4.8 million units, respectively (for uncomplicated gonorrhoea), found treatment failure after 1 week in 15.4% of men and 10.4% of women. Failure rates were reduced to 1.8% and 3.7%, respectively, when oral probenecid 1 g was given with the penicillin."... 

Another report about the treatment of pneumococcal meningitis with intramuscular or intravenous penicillin and intravenous tetracyclines (chlo-rtetracycline, oxytetracycUne, tetracycline) confirmed that the mortality was much lower in those given only penicillin, rather than the combination of penicillin and a tetracycline. fri the treatment of scarlet fever (Group A beta-haemolytic streptococci), no difference was seen in the initial response to treatment with penicillin (oral procaine benzylpenicillin) and chlortetracycUne or the penicillin alone, but spontaneous re-in-feetion occurred more frequently in those who had received both antibacterials. ... 

The principal penicillins of present importance are benzylpenicillin sodium or potassium salt (penicillin G) procaine benzylpenicillin benzathine penicillin benethamine penicillin phenoxymethylpenicillin, potassium or calcium salt (penicillin V) methicillin sodium phenethicillin sodium penicillamine hydrochloride. 

Benzylpenicillin is rapidly absoibed and rapidly excreted However, certain sparingly soluble salts of benzylpenicillin (benzathine, benethamine and procaine) slowly release penicillin into the circulation over a period of time, thus giving a continuous high concentration in the blood. Simultaneous administration of benzylpenicillin (see Fortified Proeaine Penieillin, BP) may be given initially. 

Procaine penicillin modestly extends the duration of action of benzylpenicillin. The dose is limited by the volume that can be administered intramuscularly. If the insoluble penicillins are by accident injected intravenously potentially life-threatening reactions can result. 

Proprietary Names. Apsin VK Betapen-VK Co-Caps Penicillin V-K Crystapen V (syrup and tablets) Distaquaine V-K Dowpen VK Econocil VK Icipen Ledercillin VK Megacillin Nadopen-V Novo-pen-VK Ospen (tablets) Paclin VK Penapar VK Pen-Vee-K Pfizerpen VK PVF K Robicillin VK Ro-Cillin VK Stabillin V-K Ticillin V-K Uticillin VK V-Cil-K V-Cillin K VC-K 500 Veetids. Note. Megacillin is also used as a proprietary name for benzylpenicillin potassium, clemizol penicillin, and procaine penicillin. 

Procaine penicillin, given i.m. only, is a stable salt and liberates benzylpenicillin over 12-24 h, according to the dose administered. Usually this is 360 mg 12-24-hourly. There is no general agreement on its place in therapy, and it is no longer available in a number of countries. It is best to use benzylpenicillin in the most severe infections, especially at the outset, as procaine penicillin will not give therapeutic blood concentrations for some hours after injection and peak concentrations are much lower. 

Primary and secondary syphilis are effectively treated by benzylpenicillin or procaine penicillin i.m. daily for 10-21 days. Tetracycline or erythromycin orally may be used for penicillin-allergic patients. 

Many of the medical products reviewed here find multiple applications. Thus procaine compounded with benzylpenicillin, penicillin G is an antimicrobial veterinary drug, approved in the US as a postexposure prophylaxis following inhalation of anthrax, providing that the strains do not have penicillin resistance. 

The GAG MRLs have been established on the basis of risk assessments carried out by the JECFA for benzylpenicillin," procaine pencillin, and ceftiofur. The GAG MRLs established are for benzylpenicillin in muscle, liver, kidney, and milk of all food-producing species for procaine penicillin in muscle, liver, and kidney of pigs and chickens and for ceftiofur (expressed as desfuroyl-ceftiofur) in muscle, liver, kidney, and fat of cattle and pigs." Details of residue studies considered by JECFA in recommending MRLs for GAG adoption are contained in monographs prepared for benzylpenicillin, procaine penicillin, and ceftiofur. ... 

Several therapeutically used penicillin preparations contain carbohydrates. Thus, penicillins are commonly infused in glucose or fructose solutions, sucrose is a common ingredient of penicillin syrups and benzylpenicillin procaine suspensions may contain carboxymethylcellulose as an additive. Because of the antigenic and potentially allergenic effect of penicilloyl-carbohydrate conjugates, their presence in penicillin preparations must be avoided. Information about the kinetics of reaction of penicillins with carbohydrate and factors affecting the reaction rate have recently been reported. 

The determination of total penicillins is not easy. The U,S.P. uses the direct iodimetric assay as applied to benzylpenicillin after dissolving the sample in methanol, but this may lead to results which are 3 to 5 per cent low, due to interaction of procaine with iodine. Wild suggested the use of silicotungstate as a procaine precipitant before application of the iodimetric method but details given in his method required clarification. Based on the original, the following modification has been found by us to be satisfactory. 

Repeat the iodimetric procedure using 10 ml of a standard solution of sodium benzylpenicillin in place of the 10 ml of filtrate, multiply the titration figure by 1-6520 to give the exact equivalent of each ml of 0-02N iodine in terms of procaine penicillin monohydrate and from this calculate the result of the assay. 

No effect on the colour intensity was obvious when the solutions contained high concentrations of sodium sulphate, sodium citrate, calcium chloride, 0-2 per cent sodium benzylpenicillin, 0-03 per cent procaine benzyl penicillin or 0 03 per cent penethamate hydriodide. 

In contrast to the sodium or potassium salt of benzyl penicillin, which is very water soluble and has a short duration of action, the procaine and benzathine salts (or more accurately, the ion-pair complexes) shown in Figure 8.27 are only sparingly soluble in water and very lipophilic. They are dissolved in an oily vehicle, such as ethyl oleate or sesame oil, and administered by intramuscular injection to create a depot from which the penicillin anion is slowly released into the bloodstream, achieving a sustained-release profile. An added advantage of these depot penicillins is their superior stability compared to benzylpenicillin. 

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