Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1. Pharmacodynamic properties
Pharmacotherapeutic group: peritoneal dialysis, hypertonic solutions
ATC code: B05D B
CAPD 2/3/4 is a lactate-buffered, glucose-containing electrolyte solution, indicated for intraperitoneal administration for the treatment of end-stage kidny failure of any origin which can be treated by continuous ambulatory peritoneal dialysis (CAPD).

The characteristic of continuous ambulatory peritoneal dialysis (CAPD) is the more or less continuous presence of approximately 2 litres of dialysis solution in the peritoneal cavity, which is replaced by fresh solution three to five times a day.

The basic principle behind each peritoneal dialysis technique is the use of the peritoneum as a semipermeable membrane allowing the exchange of solutes and water between the blood and the dialysis solution by diffusion and convection according to their physico-chemical properties.

The electrolyte profile of the dialysis solution is basically the same as that of physiological serum, although it has been adapted (e.g. potassium content) for use in uremic patients to enable renal replacement therapy by means of intraperitoneal substance and fluid exchange. Substances which are normally eliminated in urine, such as urea, creatinine, inorganic phosphate, uric acid, other solutes and water, are removed from the body into the dialysis solution. It should be borne in mind that medication may also be eliminated during dialysis, and that a dose adjustment may thus be necessary.

Individual parameters (such as patient size, body weight, laboratory parameters, residual renal function, ultrafiltration) must be used to determine the dose and combination with the required solutions with differing osmolarity (glucose content) and different potassium, sodium and calcium concentrations. The efficacy of therapy should be regularly monitored on the basis of these parameters.

Peritoneal dialysis solutions with a high glucose concentration (2.3% or 4.25%) are used when the body weight is higher than the desired dry weight. The elimination of fluid from the body increases in relation to the glucose concentration of the peritoneal dialysis solution.

Pharmacokinetic Properties

5.2 Pharmacokinetic properties
Uremic retention products, such as urea, creatinine and uric acid, inorganic phosphate, and electrolytes such as sodium, potassium, calcium and magnesium, are removed from the body into the dialysis solution by diffusion and/or convection.
The dialysate glucose used as an osmotic agent in CAPD 2/3/4 is absorbed slowly, decreasing the diffusion gradient between the dialysis solution and the extracellular fluid. Ultrafiltration is highest at the beginning of the dwell time, reaching a peak after about 2 to 3 hours. Later, absorption starts with a progressive loss of ultrafiltration. 60 to 80 % of dialysate glucose is absorbed.
The lactate used as a buffer is almost completely absorbed after a 6-hour dwell time. In patients with a normal hepatic function, the lactate is rapidly metabolised, as demonstrated by the normal values of intermediate metabolites.
Calcium mass transfer depends on the glucose concentration of the dialysis solution, the effluent volume, the serum ionised calcium, and the calcium concentration in the dialysis solution. The higher the glucose concentration, the effluent volume and the serum ionised calcium concentration and the lower the calcium concentration in the dialysis solution, the higher the calcium transfer from the patient to the dialysate.