A rare condition, in which patient passes up to 19 liters of urine a day (polyurea) and due to excessive fluid loss, feel thirsty all the time and drink lots of liquids (Polydipsia). This condition occurs due to decreased production of Anti diuretic hormone (ADH) or when ADH production is normal but ADH is not able to act on Kidneys (Collecting ducts specifically).  

ADH (vasopressin)

• Produced by Hypothalamus
• Posterior pituitary gland stores and releases it
• ADH makes the collecting ducts permeable by its action on V2  receptors and the water is reabsorbed in the body by the collecting ducts.
• Without presence of ADH, collecting ducts are impermeable to water and hence excess fluid loss.

Central diabetes insipidus

• Decreased production of ADH or vasopressin.
• Central diabetes insipidus is the most common type
• T/t –  Desmopressin  ( Longer acting, V2 receptor selective)
• Given orally or intranasally
• Also given orally in bed wetting in children (nocturnal enuresis)

Nephrogenic diabetes insipidus

• when pituitary gland releases enough antidiuretic hormone (ADH, or vasopressin) but
• kidneys don’t respond to ADH properly and can’t retain water.
• Thiazides diuretics are effective (shows antidiuretic effect paradoxically in DI)
• Reduces urine volume in both type of DI.

Points to remember –

Desmopressin – – Administered orally / intranasally (nasal spray)
                              – DOC for Central DI
                               – DOC for nocturnal enuresis (orally)

 Thiazide diuretics – used in renal DI
 Amiloride – DOC for lithium induced nephrogenic DI  (some drugs can also induce DI eg. lithium)
 Insulin – used in Diabetes mellitus

Hello students,

Hope you are doing great……………Today we are going to know about a very important drug in pharmacology, which is Furosemide.

Now let oversimplify the facts about Furosemide in four easy points……

(1) Furosemide belongs to Loop Diuretics group…….These loop diuretics (Furosemide, torsemide, ethacrynic acid, bumetanide act by inhibiting Na+/ K+/ 2cl– transporter in the Thick Ascending loop on the kidney (that’s why the name loop diuretic).

(2) Loop diuretics are very powerful diuretics and are also known as High ceiling diuretics, which means as the dose of these drugs increase their diuretic effect also increases even at higher levels.

(3) used in –

1. Acute pulmonary edema – it can be due to acute left ventricular failure, Quickly or dramatic response by IV furosemide (vasodilator effect cause immediate relief and then fluid reduction due to diuretic effect)
2. Edema – Highly effective in edema of all origins (Cardiac, hepatic or renal)
3. Congestive cardiac failure– help by reducing fluid overload.
4. Hypertension – though thiazide diuretics are preferred in hypertension, but we can use furosemide in hypertension with renal insufficiency, or in resistant cases in hypertensive emergencies.
5. Sometime it is used along with blood transfusion to prevent volume overload in severely anemic patients.
6. Acute hypercalcemia – like in condition of hypercalcemia of malignancy.
7. Hyperkalaemia – can be treated by furosemide, given along with Nacl and water.

(4) Side effects are-

1. Hypokalemia – dose dependent
2. Hypocalcemia
3. Magnesium depletion
4. Hyponatremia – diuresis and hyponatremia can further cause hypovolemia and hypotension, which is treated with saline infusion if needed
5. Ototoxicity – seen with higher doses especially when used IV and generally reversible. more common with other loop diuretic ethacrynic acid (in which ototoxicity is irreversible). SHOULD BE AVOIDED WITH OTHER OTOTOXIC DRUGS like aminoglycosides.
6. Hyperglycemia- Caution in Diabetes
7. Hyperuricemia
8. Allergic reactions like skin rashes are more common.

So, Lets recap- Furosemide is a High ceiling (loop) diuretic, act by inhibiting Na+/ K+/ 2cl– transporter in the Thick Ascending loop.

Useful in Left ventricular failure and edema of all origin, produce loss of K+, Ca+ Mg+ .

Hope you enjoyed the concept…………….