Pharmacology for Dentistry

390 Section 10/ Vitamins and Trace Elements

It is indicated for treatment of scurvy,
for prophylaxis of vitamin C deficiency, to
acidify urine, anaemia of vitamin C
deficiency, as antioxidant to protect natural
colour and flavour of many foods, dental
caries and increased capillary fragility.

Dosage:
Adults: Prophylaxis : 50-500 mg daily.
Pregnancy and lactation: 100-150 mg
daily.

CALCIUM

Calcium is the most abundant body
constituent (approx. 2% of body weight). It
controls excitability of nerves and muscles
and regulates permeability of cell
membranes. It act as intracellular messenger
for hormones and autacoids and help in
coagulation of blood.

Plasma calcium level is precisely regu-
lated by three hormones e.g. parathormone,
calcitonin and calciferol (which is a active
form of vitamin D). They control its absorp-
tion, exchange with bone and excretion.

Calcium is present in three forms e.g.,
as free calcium ion, bound to plasma protein
albumin and in diffusable complexes. The
endocrine system, through parathyroid
hormone and calcitonin, helps in keeping
the concentration of ionized plasma
calcium in normal level. Decrease in plasma
levels of ionized calcium leads to increased
parathyroid hormone secretion.
Parathyroid hormone tends to increase
plasma calcium level by increasing bone
resorption, increasing intestinal absorption
and increasing reabsorption of calcium in
kidney. Vitamin D acts by stimulating

intestinal absorption of calcium and

decreasing the renal excretion.

Calcium play vital role in excitation

• contraction coupling in myocardium.
  Calcium mediates contraction in
  vascular and other smooth muscles.
  Calcium is required for exocytosis and
  also involved in neurotransmitters
  release. Calcium also help in maintain-
  ing integrity of mucosal membranes and
  mediating cell adhesions. Hypercalcemia
  may occur in hyperthyroidism,
  vitamin D intoxication and renal
  insufficiency, which can be treated by
  administration of calcitonin, edetate
  sodium, oral phosphate etc. Hypocal-
  cemia may occur in hypothyroidism,
  malabsorption, osteomalacia second-
  ary to leak of vitamin D or vitamin D
  resistance, pancreatitis and renal
  failure. Hypocalcemia can be treated
  by chloride, gluconate, gluceptate,
  lactate and carbonate salts of calcium.

TRACE ELEMENTS

NICKEL

It is an essential trace element for mam-

mals, but little is known about its role or

requirement in human metabolism. In

humans, serum levels of nickel are about

1.1 to 1.6 mcg/l. This level increases in

conditions such as stroke and acute myo-

cardial infarction. A dietary requirement

for adults is about 30 mcg/day.

Nickel occurs mainly in plant foods,

especially grains and vegetables with little

in animal food sources or fats.