Pharmacokinetics of sulfadiazine/trimethoprim in neonatal male calves: effect of age and penetration into cerebrospinal fluid.

Sulfadiazine (SDZ)/trimethoprim (TMP; 30 mg of SDZ/TMP/kg of body weight) was given IV to the same 6 male calves at 1, 7, and 42 days of age and to 2 additional calves at 7 days of age. Serum concentrations of SDZ and TMP were best represented by a 2-compartment open model, but in 42-day-old calves, CSF concentrations of both drugs were best represented by a 1-compartment open model with first-order input. Between 1 and 42 days of age, the elimination half-life (t1/2(beta)) of SDZ decreased from 5.7 to 3.6 hours, and total body clearance (CLtot) increased from 1.43 to 1.88 ml/min/kg; the area under the curve (AUC0----infinity) decreased from 291.5 to 225.4 mg/L.h. The distribution coefficient (Vd(area)/kg of body weight) decreased with age, changing from 0.72 to 0.59 L/kg, between 1 and 42 days of age. Therapeutic concentrations of SDZ in serum (greater than 2 micrograms/ml) were maintained for 24 hours in 1-day-old calves and for about 15 hours in 7- and 42-day-old calves. The elimination rate of TMP increased about 9-fold; t1/2(beta) was 8.4, 2.1, and 0.9 hours, respectively, at 1, 7, and 42 days of age. Other values also reflected an increase in TMP elimination rate with age: CLtot increased from 2.8 to 12 to 28.9 ml/min/kg, k13 increased from 0.336 to 0.654 to 1.664/h and AUC0----infinity decreased from 32.8 to 7.9 to 3.1 mg/L.h, respectively. Therapeutic concentrations (greater than 0.1 microgram/ml) were maintained for 15 hours, 8 hours, and about 6 hours in 1-, 7-, and 42-day-old calves, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

[Diffusion of tetroxoprim and sulfadiazine in the cerebrospinal fluid of neurosurgery patients]. / Diffusion von Tetroxoprim und Sulfadiazin in den Liquor cerebrospinalis bei neurochirurgischen Patienten.

Two studies were conducted in neurosurgical patients to establish cerebrospinal fluid (CSF) and plasma levels of tetroxoprim (TXP) and sulphadiazine (SDZ) following the oral administration of co-tetroxazin in a standard dosage regimen. Both TXP (0,62-0,42 micrograms/ml) and SDZ (2,5-4,5 micrograms/ml) adequately penetrated into the CSF, resulting in concentrations above the MICs for most relevant pathogens. In relation to the respective plasma levels and under steady state conditions, CSF-availability is 37,5% for TXP and 31,8% for SDZ.

Diffusion of metioprim, tetroxoprim and sulphadiazine in the cerebrospinal fluid of dogs with healthy meninges and dogs with experimental meningitis.

The diffusion of metioprim (MTP), tetroxoprim (TXP) and sulphadiazine (SDZ) in cerebrospinal fluid (CSF), following single intravenous doses and continuous infusions, was studied in dogs. The drugs penetrated well into the CSF of animals with and without experimental Staphylococcus aureus meningitis. In dogs with healthy meninges, the CSF bioavailability - expressed as the ratio of CSF/plasma area under the curve 0-5-hour values - following continuous infusion was determined to be 86.7% for MTP, 58.2% for TXP and 38.8% for SDZ. In infected animals, CSF availability following continuous infusion increases slightly to ratios of 96% (MTP), 70% (TXP) and 50% (SDZ). For all drugs, the concentrations reached in CSF were above the minimum inhibition concentrations for the majority of Enterobacteriaceae, indicating their potential value in treatment of gram-negative bacillary meningitis.