Acetazolamide & Dorzolamide (topical eye drop)
MoA: Inhibits NaHCO3 reabsorptionLocation: PROXIMAL TUBULE
Sulfonamides = avoid in gout Actions:
Causes metabolic acidosis (limits H+ excretion)
Decreases aqueous humor & CSF production
CA Inhibitors Adverse
Nephrolithiasis since CaPO4 precipitates in alkaline urine
Hypokalemia (adverse effect of all diuretics except for K-sparring ones)
Contra-indicated in gout and COPD (because of effects of CA in lungs)
Therapeutic UsesOpen angle glaucomaIn combo with other diuretics to counter alkalosis
effectsEdema from heart failure
Thiazides Hydrochlorothiazide & Indapamide MoA: blocks the Na/Cl symport
Location: Acts in early DCT (diluting capacity is decreased)
Also are sulfonamides (contra for gout) Metabolic alkalosis (opposite of CA
Inhibitors) Calcium is retained HYPERCALCEMIA Only effective when GFR > 30 mL/min
Hypokalemia (more Na reaching collecting tubule causes high K secretion)
Hypercalcemia (lower intracellular Na limits Ca exchange; also limits Li excretion)
Metabolic alkalosisSexual dysfunction, postural hypotensionNot for pregnancy
Therapeutic Use1st choice for hypertensionUsed when there is any edemaCa Nephrolithiasis
Loop Diuretics Furosemide & Ethacrynic acid (not a sulfonamide) MoA: Blocks Na/K/Cl in the TAL of loop of henle
Decreased lumen positive potential = dilution ability is affected (Ca loss)
Decreased hypertonicity of medulla = decreased concentrating ability
Inhibition of macula densa sensitivity (work even with low GFR)
Osmolality is same as plasma due to loss of concentration and dilution ability!!
Metabolic alkalosis; increased Ca and Mg excretion
Loop Diuretics Only diuretics which work with low GFR!!
(due to inhibition of macula densa sensitivity) ADVERSE
Hypocalcemia, hypokalemia, hypochloremiaTinnitus (due to alteration of endolymph)Hyperglycemia in DM ptsHypokalemia can increase digoxin and Li toxicity
Therapeutic UsePulmonary edema, Heart failureHypertension – only if renal insufficiency (allows
to work with low GFR)
K+ Sparring Diuretics Triamterene; Amiloride; Spironolactone MoA:
Triamterene and Amiloride block Na channels directly Spironolactone blocks aldosterone receptors (which
prevents Na channels from even being produced) Location: late DCT & Cortical Collecting Tube
ONLY diuretics which do not cause increased K excretion
Spironolactone takes 1-3 days to take effect (blocks protein synthesis) and is metabolized to its active metabolite – canrenone
Amiloride is excreted unchanged
K+ Sparring Diuretics Adverse
Hyperkalemia (may cause asystole)Sexual dysfunction (spironolactone)Mixing with b-blockers, ACE inhibitors, NSAIDS
(renin-angiotensin system blunters) may increase hyperkalemia
Therapeutic UsesPrevention of hypokalemic statesSpironolactone for primary hyperaldosteronism
(Conn syndrome), secondary hyperaldosteronism (Cushing’s), and hypertension with heart failure
Amiloride for Li-Induced nephrogenic DI
Osmotic Diuretics Mannitol MoA: Increase the osmolarity of tubular fluid
Location: proximal tubule & thick descending limb of loop of Henle
Increases excretion of all ions Urine becomes acidic (but body is normal) Causes EXTRACELLULAR VOLUME EXPANSION initially
but then diuresis causes EXTRACELLULAR VOLUME REDUCTION !!!!!!!○ Can cause PULMONARY EDEMA
Therapeutic Use Reduces cerebral edema (neurosurgery) Reduces intraocular pressure in acute closed-angle
HIGHSCORE: Must Know Pharmacology Description: This is a book of 400+ flashcards covering 20 highly tested, and high-yield topics in pharmacology. It is designed so that you can use it anywhere on any device or print it out and use as flashcards.
If you enjoyed this presentation, please take a look at the rest of our products. Our website has many more FREE excellent presentations and tons of other FREE information.
Get the eBook: HERE!
Our site: Exam Masters Tutoring Service
RELATED PRODUCTSHIGHSCORE: Comparisons of High Yield Topics for the Medical Boards Description: This book contains over 100 comparisons of some of the most highly tested diseases and topics on the USMLE Step 2 CK. The questions on the exam are much more vague than what you see in the practice question banks and it is very difficult to differentiate between two diseases with similar symptoms. So this book is designed to help students improve their score by targeting these types of difficult questions.
Get the Free Sample: HERE!
Get the whole eBook: HERE!
View a sample Newsletter: HERE!
Subscribe to this awesome Newsletter: HERE!
USMLE STEP 2 CK TIDBITS & TIPS MONTHLY SUBSCRIPTION
Join hundreds of other students preparing for the USMLE Step 2 CK on our USMLE Step 2 CK Tidbits & Tips newsletter! It is an amazing newsletter with tons of great info. The monthly subscription entails a weekly newsletter with info such as high yield disease comparisons, most commonly tested facts, treatments & management, and much more!