Renal medication

Question 1

Nephron:

Answer 1

• its role is to maintain homeostasis of fluid and electrolyte levels, pH balance and eliminate waste products and other chemicals
• process of urine production is influenced by renal blood flow, hormones, sympathetic nervous system

Question 2

Diuretics include:

Answer 2

• loop diuretic
• thiazide diuretics
• thiazide like diuretics
• potassium sparing diuretics
• osmotic

Question 3

Diuretics:

Answer 3

• increase water and sodium excretion by the kidneys, increasing urine output
• most diuretics block sodium, water and chloride reabsorption by peritubular capillaries in the nephrons.

Question 3

Loop diuretics:

Answer 3

Loop diuretics:
- Frusemide (Lasix, Urex, Uremide)
- Bumetanide (Burinex/Burnex)
- Ethacrynic acid (Edecil, Edecrin)
Adverse effects: dehydration and electrolyte loss, excess potassium loss can lead to hypokalemia, hypocalcemia etc.

clinical considerations:
- administer routine doses in morning and midafternoon to avoid increased nocturnal enuresis
- monitor fluid and electrolyte balance
- IV administration for immediate action

• inhibit reabsorption of sodium and chloride ascending loop of Henle
• reduces reabsorption of water
• very effective diuretic
• reduces oedema
• can be used for hypertension
• normalises urine output in renal failure

Question 4

Thiazides and Thiazide-like diuretics:

Answer 4

Thiazides & Thiazide-like diuretics:
- Hydrochlorothiazide (Hydrodiuril, Microzide)
- Indapamide (Natrilex)
Adverse effects:
- dehydration and electrolyte imbalance can occur
- consider potassium supplements
- tendency to induce hypercalcemia
- can cause rise in blood uric acid levels

Clinical manifestations:
- frontline treatment for mild to moderate hypertension for people aged 65+ alone or combination with antihypertensive agents
- not recommended for first line monotherapy for hypertension in patients under 65
- start on small doses to avoid metabolic imbalances

• decrease sodium reabsorption thus reducing water reabsorption in collecting ducts and increasing urine volume

Question 5

Potassium-sparing diuretics:

Answer 5

Potassium-sparing diuretics:
- Spironolactone (Aldactone)
- Amiloride (Midamor) - combined with hydrochlorothiazide (Moduretic)

clinical considerations:
- hyperkalaemia
- K+ supplements contraindicated

• not very powerful diuretics
• occasionally given in combination with previous classes to reduce loss of potassium

Question 6

Osmotic diuretics:

Answer 6

• works by directly interfering with osmosis
• substances must be non-toxic, be excreted quickly and not be reabsorbed from glomerular filtrate
• needs to be given IV as when given oral would lead to osmotic laxative effect

Question 7

Urinary acidifiers:

Answer 7

• used to promote excretion of alkaline drugs (amphetamine, morphine)
• monitor PH
• observe respiratory rate and depth
• caution in clients with reduced lung function or cardiac oedema