AMPICILLIN IN PAEDIATRICS

Pharmacokinetics of anti-infective agents in paediatric patients

Various differences in drug disposition exist between children and adults. For example, the volume of distribution (Vd) for many drugs is larger in children than in adults. Other parameters, including excretion and elimination may be altered in children compared with adults. The penicillins and cephalosporins are used commonly for the treatment of infection in paediatric patients. The increased Vd in children contributes to the increased elimination half-life of these agents. Clearance of the acylureido-penicillins is increased in children with cystic fibrosis, a disease that decreases the elimination half-life for these drugs. Aminoglycosides distribute into extracellular fluid and their pharmacokinetic profile is affected by changes in Vd. The Vd for aminoglycosides is slightly higher in children than in adults. Children with cystic fibrosis, burns, or cancer have higher clearance rates and larger Vd values for aminoglycosides. Few data in the literature address the pharmacokinetics of other anti-infective agents, including vancomycin, teicoplanin, erythromycin, metronidazole, chloramphenicol, and cotrimoxazole (trimethoprim-sulfamethoxazole), in children. Similarly, there is little information regarding the pharmacokinetic profile of antivirals and antifungals in children. Dosage guidelines are available to enable the clinician to initiate anti-infective therapy in children. Subsequent dosage requirements may change based on the patient's current clinical condition. Although several studies have investigated the pharmacokinetics of anti-infectives in neonates and adults, data for children are limited. Therefore, further studies are required so that the ever growing arsenal of anti-infectives can be administered appropriately to children.

The oral absorption of ampicillin, pivampicillin and amoxycillin in infants and children

The oral absorption of comparable doses of mixtures of ampicillin, amoxycillin and pivampicillin was studied in 38 children from 6 months to 6 years of age. Plasma concentrations following pivampicillin and amoxycillin were higher than those following the administration of ampicillin. No significant difference was found between amoxycillin and pivampicillin. The oral absorption of pivampicillin mixture was further studied in 12 infants, 0-1 month and 1-5 months of age. The absorption was faster in infants and children more than 6 months of age than in the 1-5 months group. The excretion, indicated by the slope of the plasma concentration curve, was delayed in infants less than one month of age. The oral absorption of amoxycillin and pivampicillin from tablets was also studied in 12 infants and children, 6 months-6 years of age, in the same doses as when mixtures were studied and was more complete with pivampicillin than with amoxycillin. The absorption of pivampicillin was more complete from tablets than from mixture. Also with amoxycillin there was a trend towards more efficient absorption from tablet than from mixture.

The gastrointestinal absorption of penicillin V in children with suspected coeliac disease

The gastrointestinal absorption of penicillin V (pc-V) was investigated in 6 children, 6-12 months old, with suspected coeliac disease. The diagnosis was set after small bowel biopsy and absorption tests of vitamin A and d-xylose. As control groups served 7 children with diarrhoea but with normal small bowel biopsy and/or absorption tests and a group of 9 children with upper respiratory tract infection of the same ages as the children in the test group. The absorption of calcium pc-V in oil suspension (Penicals) was impaired in the patients with suspected coeliac disease compared to that of the control groups. There was no significantly different absorption of pc-V between the control children with diarrhoea and those with upper respiratory tract infection. After 6-8 months of gluten free diet in the children with suspected coeliac disease their absorptive ability of oral calcium pc-V in suspension form was equal with that of a control group.

The bioavailability of oral penicillin V. A comparative study of the absorption of different salts of penicillin V in children

Different salts of penicillin V (pc-V): potassium pc-V (Calciopen and Kåvepenin), calcium pc-V (Penicals) and benzathine pc-V (Meropenin) were given to 37 children (age 2 months to 4 years) with upper respiratory infections. The gastro-intestinal absorption of the drug given in a mixture was followed for three hours after administration by determination of the serum levels from capillary samples. Administration of the mixtures containing the potassium pc-V resulted in a more rapid absorption and in significantly higher plasma concentrations at 30 min than did administration of the preparations containing the calcium and benzathine salts. In four children with coeliac disease, verified by intestinal biopsy, the absorption of potassium pc-V (Calciopen) was compared with that of calcium pc-V (Penicals). A decreased absorption was found and this was most pronounced when the calcium salt was given.

Influence of diarrhea on the oral absorption of penicillin V and ampicillin in children

Oral ampicillin and penicillin V was given to 23 and 42 children, respectively, with upper respiratory infections. The absorption of the drugs was followed on one of the first days of treatment for 3 hours after administration by taking capillary samples and determining the serum levels. Approximately 60% of the children were tested for oral absorption during convalescence, 6-8 days after the initiation of the treatment. Diarrhea was evident in more than 60% of the children during treatment with both ampicillin and penicillin V. Diarrhea of short duration did not have influence on the absorption of the antibiotics. Only when persistent diarrhea over the whole therapy period existed, absorption of penicillin V was decreased.

Ampicillin blood levels as related to graded oral schedules

Twenty children, while hospitalized with pneu monia, were treated by randomization with graded dosages of oral ampicillin; five each received 50, 100, 150, or 200 mg/kg daily in four equally divided doses for at least five days. The peak serum levels rose from a mean of 1 mcg/ml with 50 mg/kg per day to 4 to 7 mcg/ml with 200 mg/kg per day. Mild to moderate diarrhea, encountered in two of the five patients of each study group, was apparently unrelated to dose, and did not hinder absorption of the drug to a clinically significant degree.