Pharmacology Vitamins Question And Answers

Vitamins

 

Question 1. Write A Short Note On Vitamin A.
Answer:

Vitamin A is a fat-soluble vitamin.

Vitamin A Chemistry And Source

• Retinol or Vitamin A₁: It is an unsaturated alcohol containing an ‘ionone’ ring. Marine fish and liver oil are good sources.
• Dehydroretinol or Vitamin A₂: It is present in freshwater fishes.

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Vitamin A Physiological Role And Actions

• Visual cycle: It is generated by the reversible oxidation of retinol and is a component of light-sensitive pigment rhodopsin which is synthesized by rods during dark adaptation. It generates a nerve impulse through a G-protein called transduction.
  • In vitamin A deficiency rods are affected more than cones: Irreversible structural changes with permanent night blindness occur if the deprivation is long-term.
• Epithelial tissue: Vitamin A promotes differentiation and maintains the structural integrity of epithelia all over the body. It promotes mucus secretion, inhibits keratinization, and improves resistance to infection.
• Reproduction: Retinol is needed for the maintenance of spermatogenesis and fetal development.
• Immunity: Increased susceptibility to infection occurs during a deficiency of Vitamin A.

Vitamin A Deficiency Symptoms

• Xerosis of the eye, keratomalacia, and night blindness progressed to total blindness.
• Dry and rough skin with papules, hyperkeratinization, and atrophy of sweat glands.
• Growth retardation and impairment of special senses.
• Imperfect enamel formation on teeth.

Vitamin A Therapeutic Uses

• It is used in prophylaxis of Vitamin A deficiency during infancy, pregnancy, lactation and hepatobiliary diseases.
• It is used in the treatment of established Vitamin A deficiency.
• In skin diseases like acne, psoriasis.
• It is used for the prevention of cancer.

Question 2. Give A Description Of Vitamin C.
Or
Write A Short Note On Vitamin C.
Or
Write A Short Note On Vitamin Used In Oral And Dental Diseases.
Answer:

Vitamin C is a water-soluble vitamin and is also called ascorbic acid.

The vitamin which is most important and useful in oral and dental diseases is the vitamin C.

Vitamin C Chemistry And Source

It is a six-carbon organic acid with structural similarity to glucose. Citrus fruits and blackcurrants are the richest source, others are tomatoes, potatoes, green chilies, cabbage, and other vegetables. Human milk is rich in vitamin C more than cow’s milk.

Vitamin C Physiological Role And Actions

• Vitamin C plays a role in many oxidative and other metabolic reactions. For example, Hydroxylation of proline.
• It directly stimulates collagen synthesis and is very important for the maintenance of intercellular connective tissue.

Vitamin C Deficiency Symptoms

• Severe vitamin C deficiency, i.e. scurvy is prevalent among sailors and is now seen only in malnourished infants, children, infants, elderly alcoholics, and drug addicts.
• Symptoms start primarily from connective tissue defects.
• Increased capillary fragility.
• Swollen and bleeding gums.
• Petechial and subperiosteal hemorrhages.
• Deformed teeth.
• Impaired wound healing.
• Anemia.
• Growth retardation.

Vitamin C Therapeutic Uses

• Prevention of ascorbic acid deficiency in individuals at risk: 50–100 mg/day.
• Treatment of scurvy: 500 to 1000 mg/day.
• Ascorbic acid enhances iron absorption and is frequently combined with ferrous salts.
• To acidify urine in urinary tract infections, i.e. 1 gm TDS.
• Large doses (0.5 to 1.5 gm) of vitamin C have been tried as prophylactic against the common cold with controversial benefits.

Question 3. Write A Short Note On Cholecalciferol (Vitamin D₃).
Or
Write A Short Note On Vitamin D.
Answer:

Vitamin D is a group of sterols and is commonly found in animals mainly, there are two types of active form- D₃-7-dehydroxy cholesterol.

Cholecalciferol Source

Fish liver oil, egg yolk, and buttermilk are the cheapest source is sunlight which forms vitamin

D₃ from its precursor is present in the skin.

Cholecalciferol Physiological Functions

• Vitamin D increases the absorption of Ca and P.
• It increases the calcification of bones in children and adults. So it is essential for the development of bones and normal growth of the body.
• It increases the excretion of phosphate by the kidney and helps in lowering serum phosphate concentration.
• It increases citrate levels of blood, bone, kidney, and heart tissues.
• It decreases pH in the lower intestinal tract which helps in increasing the absorption of calcium and phosphate.

Cholecalciferol Daily Requirements

Infants and children                                            400 IU
Adults                                                                 200 IU
Pregnant and lactating women                           400 IU

Preparations Of Vitamin D

• Ergocalciferol (Vitamin D2): Oral capsules 400 IU/day
• Cholecalciferol (Vitamin D3): Oral and IM injections
• Calcitriol: Oral capsules and solution
• Alfacalcidol and dihydrotachysterol: These are the prodrugs that are biotransformed in calcitriol in the liver.

Deficiency Of Vitamin D

• Rickets: Due to defects in bone growth and calcification of long bones in children.
• Osteomalacia: Due to defective calcification of steroid tissue in adults.

There is also delayed eruption of teeth and increased risk of dental caries due to deficiency of vitamin D.

Cholecalciferol Therapeutic Uses

• For the prevention of nutritional rickets and osteomalacia 400 IU/day of vitamin D should be given and for the treatment of nutritional rickets and osteomalacia 4000 IU/day of vitamin D is given.
• Vitamin D-resistant rickets and osteomalacia are treated with large doses of vitamin D and phosphate.
• In vitamin D dependent rickets calcidiol or alfacalcidiol is given.
• In renal rickets calcitriol or alfacalcidiol is given.
• In senile or postmenopausal osteoporosis vitamin D is given with calcium which improves the calcium balance and reduces the risk of fractures.

Question 4. Write A Short Note On The Orodental Importance Of Vitamin
A, B₂, C, And D.
Answer:

Orodental Importance Of Vitamin A

• It helps to maintain the integrity of epithelial tissue.
• It accelerates the normal formation of teeth.
• It decreases caries susceptibility.
• It causes proper growth of alveolar bone.

Orodental Importance Of Vitamin B₂

• It prevents desquamation of lips.
• It maintains the growth of teeth.
• It strengthens the mucus lining of the mouth, lips, and tongue.

Orodental Importance Of Vitamin C

• It directly stimulates collagen synthesis and is very important for the maintenance of intercellular connective tissue.
• It helps in the normal development of alveolar bone and teeth.

Orodental Importance Of Vitamin D

• The major function of Vitamin D is to maintain normal plasma levels of calcium and phosphorus.
• It is very important for the formation of teeth and alveolar bones.
• It plays an important role in the prevention of dental caries.

Question 5. Write A Short Note On Calcium And Vitamin D.
Answer:

Calcium

• After carbon, oxygen, hydrogen, and nitrogen calcium is the most abundant body constituent making up above 2% of body weight.
• Over 99% of this is stored in bones, the rest being distributed in plasma, and all tissue and cells.
• Normal plasma calcium level is 9–11 mg/dl.
• Calcium level in the body is regulated by three hormones, i.e. parathormone, calcitonin, and calcitriol.
• Calcium is stored in bone in the form of crystalline hydroxyapatite.

Calcium Physiological Role

• It controls the excitability of nerves, and muscles and maintain integrity and permeability of cell membrane.
• It is essential for excitation-contraction coupling in all types of muscles.
• Intracellular messengers for hormones.
• Impulse generation in the heart.
• Coagulation of blood.

Calcium Uses

• It is used in tetany
• As a dietary supplement during pregnancy, lactation, and in children
• Osteoporosis
• As antacid.

Vitamin D

It is the collective name given to the antirachitic substance synthesize in the body and found in food activated by UV radiations.

• D3 cholecalciferol
• D2 calciferol
• Dl mixture of antirachitic substances.

Question 6. Write A Short Note On Vitamin E.
Answer:

Alpha-tocopherol is the most abundant and potent and has vitamin E activity.

Vitamin E Dietary Source

• Wheat germ oil
• Cereals
• Nuts
• Spinach
• Egg yolk.

Vitamin E Role

• As antioxidant
• As anti sterility factor
• Enhances utilization of vitamin A
• Protect from coronary disease, Alzheimer’s disease, cataracts,s, and some cancers.

Vitamin E Deficiency

Deficiency leads to frequent abortions, neuropathy, depressed tendon reflexes, muscular dystrophy, and cardiomyopathy.

Vitamin E Therapeutic Uses

• In treatment of nocturnal muscle cramps, fibrocystic breast disease, and intermittent claudication.
• To reduce the risk of retrolental fibroplasia in premature infants.
• To prevent and treat cancer chemotherapy-induced oral mucositis.

Vitamin E Toxicity

• Even large doses of vitamin E for long periods have not produced any significant toxicity but creatinuria and impaired wound healing are reported.
• Abdominal cramps, loose motion, and lethargy are the side effects produced during toxicity.