Pharmacology for Dentistry

210 Section 4/ Drugs Acting on Cardiovascular & Urinary System

The mercury ion is capable of caus-
ing local or systemic toxicity. For local
irritation, they are combined with theo-
phylline in an attempt to diminish the
irritative toxicity at the site of injection.
IV administration may lead to ventricu-
lar arrhythmias. They cause hepatocellu-
lar damage and even precipitate hepatic
failure. They can also lead to low salt
syndrome, hypochloraemic alkalosis and
potassium depletion.

MISCELLANEOUS COMPOUNDS

Ammonium Chloride

Ammonium chloride was used earlier along
with mercurials, as they act best in acidosis,
but now-a-days, it is not used as diuretic.

It is converted to urea in liver and free
hydrogen ion are liberated in the body which
tilt the buffer system towards acidosis.

Potassium Citrate

Potassium citrate alkalinises the urine
and increases its volume. They are used to
change the pH of urine.

ANTIDIURETICS

Antidiuretic agents reduce urine volume

and are used in the treatment of diabetes

insipidus. They are classified as in table 4.7.2.

VASOPRESSIN

The antidiuretic hormone is an

octapeptide released from the posterior lobe

of pituitary gland. It is used in the treatment

of diabetes insipidus. ADH reduces the total

urine volume and absence of this hormone

cause diabetes insipidus. ADH acts on

collecting duct cells to increase their water

permeability. It acts on V2 receptors in

collecting duct and regulate their water

permeability through cAMP production.

ADH in larger dose increases the blood

pressure by direct stimulation of vascular

smooth muscle. It also stimulates the

smooth muscle of gastrointestinal tract and

increase the peristalsis. It is inactive orally

because it is destroyed by trypsin. It can be

administered by any parenteral route or by

nasal spray. Vasopressin is indicated in

diabetes insipidus and in treatment of

postoperative abdominal varices.

Table 4.7.2: Classification of antidiuretics.

I. Antidiuretic hormone (vasopressin)

Vasopressin (VASOPIN) 5-20 U SC/IM

Desmopressin (MINIRIN): 0.2-0.4 mg/day HS

II. Thiazide diuretics

Hydrochlorothiazide (Details are given in section 25-50 mg TDS

on ‘Diuretics’)

III.Miscellaneous agents

Carbamazepine (Antiepileptic drug, MAZETOL) 200-600 mg BD

Chlorpropamide (Oral hypoglycemic agent, DIABINESE) 100-50 mg OD