renal elimination

Renal elimination is the whole story of how a drug leaves the body through the kidney into the urine. It is the umbrella term that gathers the three handling steps the kidney performs and reports the net result: how much drug the kidney actually gets rid of.

Three processes combine. Glomerular filtration passively pushes free drug into the tubule; tubular secretion actively pumps more drug in; tubular reabsorption returns some back to the blood. The net amount excreted equals what is filtered plus what is secreted minus what is reabsorbed, and renal clearance is the quantitative summary of all this.

Whether renal elimination matters for a particular drug depends on its chemistry. Water-soluble, polar, low protein-bound drugs are eliminated efficiently by the kidney, so their fate is dominated by kidney function. Lipid-soluble drugs are reabsorbed and depend on metabolism instead. For renally eliminated drugs, kidney disease is the key reason to adjust the dose.