ACTIVE OR PASSIVE TUBULAR REABSORPTION

penicillin, gentamicin

Nature of drug: polar and unionized

pka: acidic basic

Mode of reabsorption/excretion: not reabsorbed passively (due to their polar nature, they require active transport mechanisms for reabsorption in the kidneys.)

phenytoin

Nature of drug: weakly acid, non polar

pka: >8

Mode of reabsorption/excretion: unionized at all pH and reabsorbed

propoxyphene

Nature of drug: weakly basic, non polar

pka: <2

Mode of reabsorption/excretion: exreted at a low rate

chromoglyic acid

Nature of drug: strongly

pka:

Mode of reabsorption/excretion:

guanethidine

Nature of drug: strongly basic

pka: >12

Mode of reabsorption/excretion: not reabsorbed ; excreted very well

NSAIDS

Nature of drug: acidic

pka: 3-8

Mode of reabsorption/excretion: Reabsorption

Morphine, TCAs

Nature of drug: Basic 

pka: 6-12

Mode of reabsorption/excretion: Depends on urine pH