Pharmacology 5

Front 1

Excretion

Back 1

Removal of drug and metabolites from the body. Kidney is most common, but also bile, lung and breast milk.

Front 2

Renal excretion

Back 2

Aka via the kidney. Majority of drug excretion. Limit duration and intensity of drugs. Decreased kidney function prolongs the duration of action and intensity of drug effects.

Front 3

The nephron

Back 3

Basic structural and functional unit if the kidney. Regulates water electrolyte and drug excretion, Ck trike blood volume,blood pressure, blood pH, and solute excretion.

Front 4

Factors affecting renal drug excretion

Back 4

Glomerular filtration, tubular secretion, tubular reabsorption.

Front 5

Glomerular filtration

Back 5

Drugs enter kidney from renal artery. Pressure within glomerulus forces low molecular weight drugs into the renal tubules. Lipid solubility and pH do not affect glomerular filtration of drugs. Only non protein bound drugs are filtered.

Front 6

Tubular secretion

Back 6

Drugs not filtered leave via efferent arteriole. Different arterioles divide to form capillaries that surround proximal tubules. Drugs can be secreted from blood into proximal tubule. Works one if two ways (for weak acids and one for weak bases).

Front 7

Tubular reabsorption

Back 7

Drugs move toward distal tubule their concentration increases due to loop of Henle. Once in distal tubule concentration exceeds that of it in the blood so uncharged lipophillic drugs just leave and go back into the blood.

Front 8

Effect of age on renal function

Back 8

Low for infants. By two it reaches normal amount. As we age it decreases.

Front 9

Biliary drug excretion

Back 9

Eliminated into bile then info the feces. For this they must 1) be molecular weight of >300 Da 2) have both polar and lipophillic groups (amphipathic) 3) are glucuronidated.

Front 10

Bile excretion continued

Back 10

Transporters on canalicular membrane if hepatocytes transport **** into bile. P-glycoprotein transports amphipathic drugs and MRP2 transports glucuronidated metabolites into bile. Either released in decreased or undergo enterohepatic recycling

Front 11

Enterohepatic recycling

Back 11

In the intestinal lumen. Bacteria cleave conjugated thing. Original drug reabsorbed. These drugs persist longer in the body.

Front 12

Pulmonary drug excretion

Back 12

Usually gasous and or highly volatile ex general anesthetics. Not heavily reliant on drug metabolism. Factors that effect it include 1) rate of respiration 2) cardiac output 3) solubility of drug in blood. High solubility=low excretion and vice versa.

Front 13

Drug excretion in breast milk

Back 13

>90% of woman take a drug first week. This means babies can be inadvertently exposed to drugs. These are 1)low protein binding 2) low molecular weight 3) high lipophilicity. Transporter breast cancer resistance protein BCRP puts it into the milk which las low pH and higher lipid content. Only few drugs do this though.

Front 14

Other routes

Back 14

Hair: we can see how long they've been exposed to it since it grows at 1cm per month. Saliva: drug is swallowed and either absorbed again or excreted in intestine. Sweat: washed away with minor amounts of reabsorption. These are minor compared to the first ones.