Mannitol- drug acting on ANS

                                                                                                                                                 MANNITOL 

MECHANISM OF ACTION-

 It appears to limit tubular water and electrolyte reabsorption in a variety of ways:

1. It retains water isoosmatically in PT – dilute the luminal fluid which opposes NaCl  reabsorption.

2. It inhibits the transport process in AscLH  which appears to be the largest contributor to the diuresis.

USES-

1. Increased intraocular tension

2. To maintain g.f.r and urine flow in impending acute renal failure

3. To counteract low osmality of plasma/e.c.f due to rapid haemodialysis

SIDE EFFECTS- 

1. Pulmonary congestion

2. Fluid and electrolyte imbalance

3. Acidosis

4. Electrolyte loss

5. Edema 

PHARMACOLOGICAL  ACTION- 

Mannitol  elevates blood plasma osmality , resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma. As a result, cerebral edema , elevated intracranial pressure, and cerebrospinal fluid volume and pressure may be reduced.

DRUG-DRUG INTERACTION- 

Mannitol + Neomycin = damage to the kidneys or hearing loss

Mannitol + Streptomycin = damage to the kidneys or hearing loss

Mannitol + Diazoxide = Diazoxide may increase the hypotensive activity of Mannitol. 

Reference- Tripathi KD "Essential of medical pharmacology" 7th edition, page no- 156,579,590,591