Affecting Urine

Question 1

Potassium sparing diuretics

Answer 1

Spironolactone (Aldosterone ant)
Amiloride (Na+)
Triamterene (Na+)

Question 2

Potassium sparing diuretics - Na+ channel blockers

Answer 2

Block sodium reabsorption by principal cells in the late distal tubule and collecting duct. This reduces the potential and k+ secretion. Also reduces H+ secretion

Question 3

Potassium sparing diuretics - Aldosterone antagonist

Answer 3

Competitive antagonist at aldosterone receptor. This reduces Na+ reabsorption and therefore K+ and H+ secretion

Question 4

Potassium sparing diuretics - indication

Answer 4

HF/HTN - with thiazides or loop
Kidney disease
Hepati cirrhosis with ascites/oedema
Spironolactone - hyperaldosteronism (primary-conns) or (secondary- CHF, LIVER DISEASE, NEPHROTIC SYNDROME)

Question 5

Potassium sparing diuretics - Adverse/Contraindication

Answer 5

Interact -
ACE inhibitors

Adverse-
Hyperkalaemia risk increased
Hyponatremia

Aldosterone inhibitiors -
Gynocomastia
Menstrual disorder
Male sexual dysfunction

Question 6

Thiazide Diuretics

Answer 6

Bendroflumethiazide
Metolazone
Chlortalidone
Inapamide

Question 7

Thiazide Diuretics - MOA

Answer 7

Act on the early distal tubule

Inhibit Na+/Cl- co-transporter. This increase the secretion of H+ and K+ into the collecting ducts. Decrease Ca2+ exretion

Question 8

Thiazide Diuretics - Indications

Answer 8

HTN
Oedema 2nd to CHF/Liver disease/ Nephrotic
Prophylaxis of calcium containing stones

Question 9

Thiazide Diuretics - SE

Answer 9

hypokalaemia
hyponatremia
hypercalcemia
metabolic alkalosis 
Caution:
Cardiac glycosides
DM - may cause hyperglycaemia

Question 10

Osmotic Diuretics

Answer 10

Mannitol

Question 11

Osmotic Diuretics - MOA

Answer 11

Act on proximal tubule/descending LOH/ Collecting ducts
(water permeable parts)

Freely filtered in glomerulus and not reabsorbed. Water reabsorption is reduced because of presence of solute

Question 12

Osmotic Diuretics - indications

Answer 12

raised intracranial pressure or (intraocular)

Question 13

Osmotic Diuretics - contraindications

Answer 13

CCF/ Pulmonary Oedema –> can increase blood volume
Adverse-
Chills and Fever

Question 14

Alpha Blockers -

Answer 14

prazosin

doxazosin

Question 15

Alpha Blockers - MOA

Answer 15

Relax the smooth muscle at the urethra and opening of the bladder.
Helps flow.

Question 16

Alpha Blockers - SE

Answer 16

Vasodilators in cardiac disease so can increase risk of hypotension

Question 17

Parasympathomimetics

Answer 17

bethanechol

Question 18

Parasympathomimetics - MOA

Answer 18

Increase detrusor muscle activity

Helpful in bladder outlet obstruction but no relief for acute urinary retention.

Question 19

Parasympathomimetics - SE

Answer 19

Sweating
Bradycardia

Catheters used more now

Question 20

Mirabegron

Answer 20

relaxes detrusor by activating b3 receptor
used in treatment of overactive bladder
stops urgent, frequent and uncontrolled urination

Question 21

Antiandrogens -

Answer 21

Finasteride

5alpha reductase inhibitor. inhibits conversion of testosterone to dihydrotestosterone = reduced size of prostate and better urinary flow

Question 22

Tamsulosin - alpha blocker

Answer 22

Difficulty in beginning the flow of urine, weak stream, and the need to urinate often or urgently (including during the middle of the night)

avoid in HTN

Question 23

Antimuscarinics

Answer 23

Oxybutanin

Used in urge incontinence, frequency, urgency
Relaxation of detrusor muscle

Question 24

Loop Diuretics -

Answer 24

Furosemide, bumetanide, torsemide

Question 25

Loop Diuretics - MOA

Answer 25

Act on thick ascending branch of LOH

Inhibit Na+/K+/Cl- cotransporter in the luminal membrane. increased Na+ and Cl- excretionResults in increased sodium reaching the collecting duct and therefore increases K+ and H+ secretion

Inhibits Ca2+ and Mg reabsorption reduced (reduced membrane potential)

causes venodilation therefore relief before diuresis

Question 26

Loop Diuretics - Indications

Answer 26

Pulmonary oedema
oliguria due to AKI
Resistant CHF and HTN

Question 27

Loop Diuretics - Contraindications

Answer 27

severe renal impairment

Caution;

• cardiac glycosides (hypokalaemia increases effect and increases chance of arrhythmias)
• interact with amino glycoside antibiotics