Antidiuretics encompass agents like vasopressin (ADH) and its analogs, which reduce urine volume by acting on specific receptors in the kidneys and blood vessels. They are used for conditions like diabetes insipidus and nocturia, with desmopressin being the preferred choice due to its high potency and favorable pharmacokinetics. Potential side effects can include headache, nasal irritation, and systemic complications like bradycardia.

1. ANTIDIURETICS
DR.G.VANITHA.M.D

2. INTRODUCTION
 DEFINITION:
Reduce the urine volume(DI)
ANTIDIURETICS
Antidiuretic hormone and Its analogues
Vasopressin (ADH)
Desmopressin
Lypressin
Terlipression

3. NATRIURETICS
Thiazide
amiloride
MISCELLANEOUS
Carbamazepine
Chlorpropammide
Indomethacin

4. ANTIDIURETIC HORMONE (Arginine
Vasopressin-AVP)

6. RECEPTORS DISTRIBUTION
 G protein coupled cell membrane receptors
 V1 Receptors
 phospholipase C- lP/ DAG pathway
 1.vasoconstriction
 2. visceral smooth muscle contraction
 3.glycogenolysis
 4.platelet aggregation,
 5.ACTH
 DAG mediated protein kinase C activation

7. PHARMACOLOGICAL ACTIONS
KIDNEY
Blood vessel
BLOOD
CNS
UTERUS
GIT

8. KIDNEY-CD(principle cell)

10.  BLOODVESSEL
VI receptors
Increases peripheral resistance
vascular smooth muscle hypertrophy.
 GIT
Increased peristalsis in Gut

11.  UTERUS
contracted AVP acting on oxytocin receptor
CNS
Peptide neurotransmitter brain and spinal cord.
Regulation of body temperature
Systemic circulation,
ACTH release,
BLOOD
AV P induces platelet aggregation
FactorVIII and von Willebrand's factor (V2 receptors)

12. PharmacokInetics
ROUTES
1.PARENTRAL(i.m,s.c,i.v)
2.INTRANASAL
Inactive orally (trypsin)
METABOLISM
Liver-Enzymatic cleavage
kidney
t½ is short ~ 25 min

13. VASOPRESSIN ANALOGUES
1.Vasopressin
2. Lypressin
3.Terlipressin
4.Desmopressin (dDAVP)
5.Felypressin

14.  Vasopressin(V1,V2)
 Short duration(20min)
 Any route
 Lypressin ( 8-lysine vasopressin)
 V1
 Longest action 4-6hrs (i.m,s.c)

15.  Terlipressin
 Prodrug
 Bleeding esophageal varices
 Less severe adverse effects
 Longer acting

16.  Felypressin -V1
 Short duration(20min)
 Vasoconstriction+local anaesthetics
prolong action

17. Desmopressin (dDAVP)
V2 agonist
More potent ,Longer acting
Negligible vasoconstrictor
 Desmopressin is the preparation of
choice for V2 receptor related indication


18.  The intranasal route is preferred IO to
20%
 oral formulation bioavailability of 1- 2%;
oral dose is 10-15 times higher than the
intranasal dose
 oral tablet more convenient

19. Uses
 Based onV2 actions (Desmopressin is the
drug of choice)
 I . Diabetes insipidus
DI of pituitary origin (neurogenic) is the
most important indication
Ineffective in renal (nephrogenic)
Dose of desmopressin is individualized by
measuring 24 hour urine volume.

20.  2. Bedwetting in children and nocturia in
adults
 lntra nasal or oral desmopressin at
bedtime
 3.Renal concentration test
 i.m. of aqueous vasopressin or
desmopressin maximum urinary
concentration urinary specific gravity.
 4. Haemophilia, von Willebrand's disease

21. Based onV1 actions
 I. Bleeding esophageal varices Vasoprcssin/
terlipressin mesenteric blood vessels
allowing clot formation
Sclerotherapy
 2. Before abdominal radiography
lypressin -drive out gases from bowel

22. Adverse effects
 Transient headache / flushing
 local application
Nasal irritation, congestion, rhinitis , ulceration and
epistaxis
 Systemic :
 belching, nausea,
 urge to defecate
 seizures. Children are more susceptible
 Bradycardia
 Precipitate angina by constricting coronary vessels.
 Urticaria

23. VASOPRESSIN ANTAGONISTS
 Tolvaptan
 orally hyponatraemia due to C HF,
 cirrhosis of liver
 (SIADH).
 thrombotic complications due to
haemoeoncentralion, thirst and dry mouth
 CYP3A4
 Mozavaptan (V2)
 Conivaptan (V1+V2 )

24. THIAZIDES
 Neurogenic and Nephrogenic DI
 Hydrochlorothiazide 25- 50 mg TDS
Amiloride
lithiuminduced nephrogenic DI
block entry of Na+ in the principal cells of
CD, it also blocks Li entry
Indomethacin
renal DI reducing renal PG synthesis