CACA ( Calcium Carbonate + Calcitriol )

CALCIUM CARBONATE

After C, O, H & N Calcium is the most abundant body constituent.

It makes up about 2% of body wt. i.e. 1-1.5 kg in an Adult.

Over 99% of this is stored in Bones, the rest being distributed in Plasma and all Tissues and cells

CALCIUM CARBONATE (40% Ca)

It is insoluble, tasteless and non-irritating

It has been used as an Antacid reacts with HCL to form Chloride which may be absorbed from the Intestine.

Physiological roles -:

Calcium controls excitability of nerves & muscles and regulates the permeability of cell membrane. It also maintains integrity of cell membranes and regulates cell adhesion.

Ca+2 ions are essential for excitation-Contraction coupling in all types of muscles & excitation-secretion coupling in exocrine & endocrine Glands.

It acts as intracellular messenger for hormones, autacoids & transmitters.

Impulse generation in Heart.

Coagulation of Blood.

Plasma Calcium level -:

It is precisely regulated by 3 Hormones almost exclusively devoted to this function,

Paratharmone

Calcitonin

Calcitriol (active form of Vitamin D)

Normal Plasma Calcium is 9-11 mg/dl

Absorption & excretion -:

Ca is absorbed by facilitated diffusion from the entire small intestine as well as from Duodenum by carrier mediated active transport under the influence of Vitamin D.

Phytates, Phosphates, Ocalates & Tetracyclines complex Ca+2 ion in an insoluble form in the intestine & interfere with absorption.

Glucocorticoids & Phenytoin also reduce Ca absorption.

About 300 mg of endogenous Ca is excreted daily half in Urine & half in fasces.

Side effects -:

Calcium supplements are usually well tolerated, only G.I side effects like,

Constipation

Bloating

Excess Gas have been reported.

INDICATIONS (UESES)

As dietary supplement specially in,

Growing children

Pregnant, Lactating & Menopausal woman.

In Elderly Patients

In various Ca deficiency states,

Osteoporosis

Osteomalacea

As Antacid

THE DIETARY ALLOWANCE RECOMMENDED BY NATIONAL INSTITUTE OF HEALTH 1994

Children 1-10 years . 8-1.2 gm

Young Adult 11-24 years 1.2-1.5 gm

Pregnant & Lactating Women 1.2-1.5 gm

Men 25-65 Years 1.0 gm

Woman 25-50 Years 1.0 gm

Woman 51-65 Years (if taking HRT) 1.0 gm

Woman 51-65 Years (if not taking HRT) 1.5 gm

Every one > 65 Years 1.5 gm

CALCITRIOL

Calcitriol is the Primary active metabolite of Vitamin D.

It is a Product of 2 successive hydroxylations of vitamin D.

The initial step in activation of Vitamin D occurs in Liver and the final activation to Calcitriol occurs primarily in the Kidney.

Actions -:

Calcitriol enhances absorption of Ca and Phosphate from intestine. This is brought about by increasing the synthesis of a carrier protein for Ca +2 called Calcium binding Protein or Calbindin.

Calcitriol enhances re absorption of Calcium & Phosphate from Bone by promoting recruitment and differentiation of osteoblast precursors in the Bone remodeling units. It’s action is independent of but facilitates by Paratharmone.

Actions -:

It enhances tubular re absorption of both Calcium & Phosphate in Kidney but the action is less marked than that of Paratharmone.

Actions of Calcitriol on immunological cells, lymphokine production proliferation & differentiation of epidermal and certain malignant cells, neuronal and skeletal muscle function have also been demonstrated.

Contraindications -:

Hypercalcaemia

Evidence of Vitamin D

Malabsorption syndrome

Hypervitaminosis D

Decreased Renal function

Adverse effects -:

Over dose leads to Hypercalcaemia with fatigue

Vomiting

Diarrhoea

Polyuria

Nephrocalcitosis

Rarely Coma

Interactions -:

Hypermagnesemia may develop in patients on chronic Renal dialysis.

Intestinal absorption of Calcitriol may be reduced by Cholestyramine.

Phenytoin, Barbiturates

Reduce efficacy of Vitamin D.

INDICATIONS -:

Management of Hypocalcaemia in patients on chronic Renal dialysis.

Hypoparathyroidism.

Along with Calcium in various Calcium deficiency states.

Vitamin D resistant and Vitamin D dependent Rickets.

Renal Rickets.