Excretion of drugs in urine, bile and milk

Question 1

What drugs are excreted in expired air

Answer 1

High vapour pressure

Question 2

Which drugs are excreted in urine

Answer 2

Water soluble/metabolites which are small

Question 3

Which drugs are excreted in bile

Answer 3

bigger water soluble drugs

Question 4

Which drugs are excreted in sebum/sweat

Answer 4

Very minor- tetracycline in sebum (contributes to use in acne)

Question 5

Which drugs are secreted in breast milk

Answer 5

Most drugs present in maternal blood detectable in milk

Question 6

What does excretion in bile serve as an alternative route for

Answer 6

Excretion of polar drugs in patients with renal impairment

Question 7

Whta do some drugs undergo when excreted in Biel

Answer 7

Enterohepatic recirculation (drug exits liver and into intestines then gets reabsorbed back into liver. This increases half life)

Question 8

Consequence of enterohepatic recirculation

Answer 8

Increases half life of drug (ezetimibe)

Localises the site of drug action (e.g. loperamide + budesonide)

Question 9

What should you always monitor when using methotrexate

Answer 9

Renal function

Question 10

Route of renal handling of drugs

Answer 10

1) Glomerular filtration
2) Active secretion (drug passes from blood into tubular fluid and is removed from body)
3) Passive reabsorption

Question 11

How do protein bound drugs get excreted

Answer 11

In active secretion

Question 12

What separate mechanisms are there for active secretion in kidney

Answer 12

Separate mechanisms for acids and bases

Question 13

What should not be used with methotrexate and why

Answer 13

Salicylate (found in NSAIDs and aspirin type drugs) because this is in competition with methotrexate and causes plasma levels of methotrexate to rise and become toxic

Question 14

What can pH of urine affect

Answer 14

Amount of drug which is reabsorbed

Question 15

What drugs should you use when there is renal impairment

Answer 15

Choose short acting agents

Increase dosage interval in renal impairment (gentamicin)

Choose non-really excreted alternatives

Question 16

Which drugs should be avoided in renal impairment

Answer 16

Metformin

Question 17

Which drug are ineffective in renal impairment

Answer 17

thiazide diuretics

Question 18

How is loading dose affected in renal impairment

Answer 18

Not affected

Question 19

Considerations in prescribing in hepatic impairment

Answer 19

Hepatic clearance 
Protein binding
Sodium and fluid retention
Effects on coagulation (INR may be increased)
Gastric effects 
CNS effects 
Sedation

Question 20

What drugs do avoid when breastfeeding

Answer 20

Anticancer drugs 
Amiodarone 
Lithium
Iodine containing radiocontrast media 
Tetracyclines