Drugs and the Kidney

Question 1

What is the pharmacokinetic profile of penicillin

Answer 1

1- oral absorption variable
2-widely distributed in body fluids
3- mainly renal excretion ( tubular secretion )
4- short plasma half- life

Question 2

What happens to medications someone is taking if they become renal impaired

Answer 2

Dose often will have to be adjusted if the drug is eliminated by the kidneys

Question 3

What happens to Tazocin dosage in the event of renal impairment

Answer 3

Dose is adjusted by extending the time period between each dose from 8 hours to 12 hours. Same amount is still given but dose is reduced in 24 hr period

Question 4

List drugs that will become less effective in renal impairment and their alternatives

Answer 4

1- Thiazide diuretics
Alternative : Loop diuretics
2- Nitrofurantoin ( antibiotic )
Alternative : Trimethoprim

Question 5

What drugs will have an increased effect due to renal impairment

Answer 5

Opioids or Sedatives

Question 6

What drugs will have increased toxicity in renal impairment and list the the results

Answer 6

1- Digoxin ( arrhythmias/nausea)
2- K+ sparring diuretics ( hyperkalaemia )
3- Nitrofurantoin (neuropathy)
4- Tetracyclines ( increased protein breakdown)
5- Metformin ( lactic acidosis)

Question 7

60% of AKI occurs due to what and why

Answer 7

Pre-renal impairment due to decreased renal perfusion and altered auto regulation

Question 8

What can cause sudden changed in blood volume causing pre-renal impairment

Answer 8

1- Vomiting / Diarrhoea
2- Bleeding
3- Cardiac Failure
4- Cirrhosis

Question 9

What is most effected with drops in BP

Answer 9

Brain and Kidneys

Question 10

What is the medical regimen for pre-renal impairment AKI

Answer 10

Discontinue nephrotoxic drugs and support blood pressure

Question 11

List drugs that can cause Pre-renal impairment ( Hint : 4 )

Answer 11

1- Diuretics: reduce blood volume = reduce blood flow
2- Antihypertensives : ACE inhibitors, ARBS and vasodilators
2- NSAIDs : can cause peripheral oedema
3- Ciclosporin ( DMARD )
4 Radio contrast media

Question 12

List drugs that cause intrinsic renal impairment AKI ( Hint: 9)

Answer 12

1- Aminoglycosides ( gentamicin ) 
2- Amphotericin B 
3- Antimicrobials 
4: Anti-platelets (clopidogrel )
5- Anti-convulsants 
6- DMARDs 
7- Lithium 
8- NSAIDs 
9- Radio contrast media

Question 13

What can cause post-renal impairment AKI

Answer 13

1- Crystals / Stones
2- Retroperitoneal fibrosis
3- prostate enlargement

Question 14

What drugs can cause stones or crystals (not super important , extremely rare)

Answer 14

1- Aciclovir

2- Methotrexate

Question 15

What drugs can cause retroperitoneal fibrosis ( not super important , extremely rare)

Answer 15

1- Ergot derivatives ( for migrant not used anymore )
2- Methyldopa
3- Hydralazine
3- atenolol

Question 16

What are specific drugs to look out for for AKI ( Hint:7)

Answer 16

1- NSAIDS 
2- ACE-I / ARBS 
3- Diuretics 
4- lithium 
5- Digoxin 
6- Gentamicin 
7- Methotrexate

Question 17

Are NSAIDs nephrotoxic

Answer 17

yes all of them are

Question 18

What can NSAIDs do to kidney

Answer 18

1- acute tubular necrosis
2- interstitial nephritis
3- glomerulonephritis
4- renal papillary necrosis

Question 19

Explain the relationship with ACE-I and ARBs with renal impairment

Answer 19

Can help and harm the kidney ( complex ) .
Help : control BP and reduce intra glomerular pressure, reduce proteinuria
Harm: associated with deterioration of renal function

Question 20

If there is hyper filtration what could improve Kidney function

Answer 20

ACE-I & ARBs

Question 21

If someone has AKI would you continue ACE-I & ARBS

Answer 21

No have to stop them because there is a hypo filtration problem not hyper.

Question 22

Where is ACE-I & ARBs contraindicated

Answer 22

with renal artery stenosis

Question 23

Why would Diuretics be stopped if patient has AKI (Hint: 5 reasons )

Answer 23

1- increase electrolyte disturbances when combined with other diuretics.
2- Loop diuretics have increased nephrotoxicity if combined with antibiotic.
3- Will cause diuresis if combined with NSAIDs
4- Cause hypotension if combined with ACE-I and ARBs
5- Will cause lithium toxicity if combined with lithium

Question 24

How is lithium excreted

Answer 24

By Kidneys

Question 25

Why should Lithium be stopped if there is severe renal impairment ( Hint: 3 reasons)

Answer 25

1- Can block the effect of ADH on kidney and cause diabetes insipidius 2- Long term can cause tubule-interstitial damage 3- if prescribed with diuretics or ACE-I can cause lithium toxicity

Question 26

What is lithium used for

Answer 26

Psychological disorders such as bipolarism

Question 27

How is Digoxin excreted and what happens as time to steady state increase

Answer 27

Excreted by the kidneys. As time to steady state increases renal function decreases.

Question 28

What can result in Dig toxicity

Answer 28

If there is Hyperkalaemia.

Question 29

How is Gentamicin excreted

Answer 29

By the kidneys

Question 30

Is gentamicin nephrotoxic

Answer 30

yes

Question 31

If gentamicin levels go up what happens to renal function

Answer 31

Renal function will go down

Question 32

If patent on gentamicin has renal impairment what should you do

Answer 32

Reduce dose and frequency. Instead of 300 mg daily make it 300 mg 36-hrly. Need to measure trough levels and U+ E a lot more often

Question 33

What is the medical regimen for drug-induced AKI

Answer 33

``` 1- reversible if detected early 2- look at serum creatinine and eGFR 3- look at urinary sediment 4- stop nephrotoxic drugs 5- give supportive treatment ( ex: IV fluids ) ```

Question 34

What is the threshold eGFR that signals CKD

Answer 34

anything less than 60ml/min

Question 35

What happens if patient's eGFR decreases below 30 ( level 4 )

Answer 35

Referred to nephrology for dialysis, kidney transplant

Question 36

What happens if eGFR is less than 15 ( level 5 )

Answer 36

Established kidney failure. Put on permanent dialysis

Question 37

Does the loading dose stay the same or change during renal impairment

Answer 37

Stays the same since loading dose is not affected by clearance but maintenance dose does so that needs to be adjusted.

Question 38

How is dose adjustment usually done

Answer 38

Via eGFR or serum creatinine

Question 39

Treatment for severe CKD ( and reasons for them )

Answer 39

1- Phosphate binding agents ( calcium carbonate ) : to keep calcium levels normal 2- Secondary HyperPTH / renal osteodystrophy : vitamin D tablet 3- symptomatic anaemia : erythropoietin may be used 4- Dialysis / renal replacement therapy

Question 40

What is Dialysis

Answer 40

1- Blood is put through artificial filtration system | 2- Solutes diffuse from blood and diffuse into fluid ( mirror what kidneys do )

Question 41

What drugs can be affected by dialysis and why

Answer 41

Drugs that are small molecules and have low protein binding will be removed. Will have to be reduced after dialysis Ex: Theophyline, Metronidazole, Gentamicin, Anti-virals

Question 42

Explain Dialysis in acute poisoning and examples when it is used

Answer 42

Used in acute poising by drugs to diffuse drug molecules out. Ex: aspirin, lithium , methanol , sodium valproate, ethylene glycol

Question 43

Which drugs should be stopped / adjusted first when patient comes in and presents with eGFR of 20

Answer 43

Diuretics , ACE-I, metformin , NSAIDs ( DAMN drugs ). | Digoxin should be assessed for toxicity and dose be reduced

Question 44

What is Bumetanide

Answer 44

A diuretic

Question 45

What's the rule for drug half life

Answer 45

1- f drug is given once, 5 times the half life is how long it takes to eliminate the drug 2- if drug is given regular then 5 times the half life is when the drug will reach the steady state

Question 46

If there is a regulary given drug with a half life of 4 days when should the plasma drug concentration of steady state be measured.

Answer 46

around 20 days after