Dosing of Cephalosporin in Renal Failure Patients - Essay Example

"Dosing of Cephalosporin in Renal Failure Patients" is an astonishing example of a paper on drug therapy. 
Kidneys are the imperative organs of the body, kidney diseases influence all the other organs as they regulate the fluid level of the body. Any kind of physiological alterations related to renal disease displays prominent outcomes on the pharmacology of many drugs. It is therefore vital for the physicians to have an appropriate consideration of biochemical and physiological acts of drugs, for renal diseases. The chief constraint determining renal function relevant for drugs excreted through the kidney is GFR (Glomerular Filtration Rate) and Creatinine clearance rate (Clcr).

Aim- To understand the dosing of Cephalosporin in Renal failure patients.

Method and Design

Physical examination- should be performed for oedema, ascites, dehydration. Measurement of body weight and height is performed. In obese patients, the ideal body weight should be calculated and the dose of the drug should be planned consequently.

Renal function- Estimation of creatine clearance (the volume of blood plasma that is cleared of creatinine in unit time). Elimination of drugs is directly proportional to GFR (drugs excreted by kidneys). The Cockroft- Gault equation to estimate Clcr for age between 40- 80 years.

Clcr (mL/min) = (140-age)x weight in kgs / 72 x serum creatinine (in mg/ dL) x (0.85 for women).

Assessment of GFR from serum creatinine level presumes the stability of renal function and also formulate that serum creatinine measurement is constant. If there is an alteration in renal function, the creatinine level does not indicate the true clearance. In the case of oliguria, Clcr is approximated as 10mL/min.

In cases with acute renal failure, the non-renal clearance of medicines diminishes by means of the time window of renal failure. In the initial course of the therapy, the personalized pharmacokinetic dose for patients with severe renal impairment is vital. In the case of oedema or ascites, the huge preliminary dose is necessary to procure a therapeutic plasma drug level rapidly. Consequently, the maintenance level lower than the lethal level is essential. As soon as the loading dose is administered, the therapeutic range is accomplished rapidly. It is imperative to understand that a loading dose is considered in the case if the half-life of a drug is predominantly lengthy as in the case of renal failure or as soon as vital therapeutic plasma level is attained at a faster pace. Protection or maintenance dose is specified after measuring the renal function, consequently, dosage strategy for patients with normal and impaired renal function are provided in the table.

Patients are categorized as- Moderate (Clcr 10-50 mL/ min),  Severe (Clcr <10mL/min) and Post hemodialysis dose

Drug

Peak Serum Level (mcg/mL) after 1g IV

Serum Half-life (Min)Total Daily Dose (mg/ kg)

Total daily dose (mg/ kg)

Dosage interval (hrs)

Moderate (Clcr 10-50 mL/ min)

Severe (Clcr <10mL/min)

Post hemodialysis dose

Cephapirin

40-60

40

50-200

4-6

1-2 g q6-12h

1 g q12h

1 g

Cefadroxil (Oral agent)

15

75

15-30

12-24

1 g daily

0.5 g daily

0.5 g

Cefuroxime

80-100

80

50

6-12

1 g q12h

1-2 g daily

0.5 g

Cefprozil

10

90

10-15

12

0.5 g q12-24h

0.25-05 g q12-24h

0.5 g

Ceftazidime

100-120

120

50-75

8-12

1 g q12h

0.5-1 g daily

05 g

Cefoperazone

150

120

30-200

8-12

1-2 g q12h

1-2 g q12h

None

Inclusion criterion

1. Patient receiving Cephalosporins which are mainly excreted through kidneys require dosage adjustment in renal insufficiency e.g. Cepharin, Cefadroxil, Cefuroxime, Cephalothin etc.
2. Age- Creatinine clearance decreases with the advancing age as GFR (Glomerular Filtration Rate) progressively declines (intact nephron loss). GFR is- 75% at 50 years and 50% at 75 years of age as compared to young adults.
3. History of previous drug allergy or toxicity

Exclusion criterion

1. Patients with normal renal function.
2. Patients on Ceftriaxone as it is primarily excreted by biliary excretion hence requires no dosage adjustment in renal insufficiency.
3. Patients with chronic liver disease.