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Right option is (B) False

Easy explanation: Carbonic anhydrase inhibitors inhibit carbonic anhydrous, THUS prevents the exchange of H+ ions with sodium and water. The enzyme carbonic anhydrase helps to make H+ ions available so they can be exchanged with sodium and water in the proximal tubules. Whereas OSMOTIC diuretics such as mannitol pull water into the blood vessels and nephrons from the surrounding tissues, REDUCES cellular edema, increase urine PRODUCTION causing diuresis. The working of both the drugs are different but both of them helps in decreasing the fluid content.

Correct choice is (b) False

To explain I would SAY: Osmotic diuretics such as mannitol PULL water into the blood vessels and nephrons from the surrounding tissues, reduces CELLULAR edema, increase urine production causing diuresis. That is why we can use osmotic diuretics during severe head injury. Pulling water from the surrounding blood vessels is not a function of thiazide LIKE diuretics.

Correct choice is (b) Loop diuretics

The explanation: Loop diuretics ACT directly on the ascending limb of the loop of Henle to inhibit sodium and chloride resorption and provides with RAPID diuresis. Edema associated with HEPATIC or renal disease, control of HYPERTENSION, increase renal EXCRETION of calcium in patients with hypercalcemia, useful when rapid diuresis is desired because of the rapid onset of action.

The correct OPTION is (a) Osmotic diuretics

Easiest explanation: Osmotic diuretics such as mannitol pull water into the blood vessels and nephrons from the surrounding tissues, REDUCES CELLULAR edema, increase urine production causing diuresis, and reduces excessive INTRAOCULAR pressure. Loop diuretics act directly on the ascending limb of the loop of Henle to INHIBIT sodium and chloride resorption.

Correct answer is (b) HYPERTENSION and hypercalcemia

The best I can explain: Loop diuretics act directly on the ascending limb of the loop of HENLE to inhibit SODIUM and chloride resorption. Edema associated with HEPATIC or renal disease, control of hypertension, increase renal EXCRETION of calcium in patients with hypercalcemia, useful when rapid diuresis is desired because of the rapid onset of action.

Right answer is (c) Glaucoma and epilepsy

Easiest explanation: Carbonic anhydrous inhibitors are USED with miotics to lower intraocular pressure before OCULAR surgery in certain cases. These are also useful in the treatment of Glaucoma, EDEMA, epilepsy, high-altitude sickness. They work by INHIBITING carbonic anhydrous, thus prevents the exchange of H+ ions with sodium and water.

Correct answer is (d) Distal tubule

Easy explanation: Potassium-sparing diuretics WORK in collecting ducts and distal convoluted tubules. It interferes with SODIUM-potassium EXCHANGE, competitively bind to ALDOSTERONE receptors, and block the resorption of sodium and water usually induced by aldosterone. Prevent potassium from being pumped into the tubule, thus preventing its secretion. Competitively block the aldosterone receptors and inhibit its action thus the EXCRETION of sodium and water is promoted.

Correct answer is (a) Proximal tubule

The BEST I can explain: Acetazolamide is carbonic anhydrase inhibitor, they work by inhibiting carbonic anhydrous, thus PREVENTS the exchange of H+ ions with sodium and water. The enzyme carbonic anhydrase helps to make H+ ions available so they can be exchanged with sodium and water in the proximal tubules. Inhibition of carbonic anhydrase reduces H+ ion CONCENTRATION in the RENAL tubule, as a result, there is increased excretion of bicarbonate, sodium, water, and potassium resorption of water is decreased and urine VOLUME is increased.

The correct option is (a) Proximal tubule

Explanation: Osmotic diuretics work in the proximal tubule, producing an osmotic effect. It pulls water into the BLOOD vessels and nephrons from the surrounding TISSUES. Osmotic diuretics reduces cellular edema, increased urine production, causing DIURESIS. Rapid EXCRETION of water, sodium, and other electrolytes, as well as excretion of TOXIC substances from the kidney. Reduced excessive intraocular pressure.

Right option is (d) 50% of SODIUM is absorbed in the glomerulus

The best I can explain: We are aware of the fact that where sodium goes water follows. 20-25% of all sodium is reabsorbed into the bloodstream in the loop of Henle. 5-10% gets reabsorbed in the distal tubes and 3% of the sodium gets reabsorbed in collecting ducts. Thus is sodium is not reabsorbed, water will also not GET reabsorbed thus MAKING water excreted as URINE.

Correct choice is (a) True

The best explanation: HISTAMINE, when released, causes inflammation by increasing vasodilation, capillary PERMEABILITY, causing SMOOTH muscle contraction, mucus secretion, and parasympathetic NERVE stimulation. Formed from the AMINO acid Histidine in a decarboxylation reaction with the enzyme histidine decarboxylase. Occurs primarily in mast cells and basophils.

Correct choice is (d) Chlorphenamine

Easy explanation: Ethylenediamine were the first group of clinically EFFECTIVE H1-antihistamines for example mepyramine. Diphenhydramine is of ETHANOLAMINE class. Chlorphenamine is of alkylamine class these drugs have FEWER sedative and GI adverse EFFECTS, but a greater INCIDENCE of CNS stimulation. Cyclizine is of piperazines class.

Correct option is (b) Diphenhydramine

The explanation: Ethylenediamine consists of mepyramine. Diphenhydramine is of ethanolamine has significant anticholinergic SIDE effects and sedation. Chlorphenamine is of alkylamine class. CYCLIZINE is of piperazines class, structurally related to the ethylenediamines and the ethanolamines used most often to treat motion sickness, vertigo, nausea, and VOMITING.

Right option is (a) LORATIDINE

Best explanation: Loratidine is the only drug of its class available over the counter. It has long lasting effects and does not cause drowsiness because it does not cross the BBB. Terfenadine was formerly USED to treat allergic conditions. In the 1990’s it was removed from the market due to the increased RISK of cardiac ARRHYTHMIAS.

Right answer is (a) Piperoxan

To ELABORATE: Piperoxan is discovered in 1933 by Jeff Forneau and Daniel Bovent while DEVELOPING a GUINEA pig animal model of anaphylaxis. They RECEIVED the Nobel Prize in 1957. Classes of first-generation H1 receptor antagonist antihistamines are ethylenediamines, ethanolamines, alkylamines, piperazines, TRICYCLICS.

The correct option is (b) H2 receptor

The best I can EXPLAIN: Found mainly in the gastric parietal cells, a low LEVEL of these cells can be found in vascular smooth muscles, NEUTROPHILS, CNS, heart, uterus. These are G protein-coupled receptor. Increases the release of gastric acid. H1 receptors mediate an increase in vascular PERMEABILITY at sites of inflammation induced by histamine.

The CORRECT option is (B) 48%

Easiest EXPLANATION: Allergies are caused by a hypersensitivity reaction of the antibody class IgE which are located on mast cells in the tissues and basophils in the blood. When an allergen is encountered, it binds to IgE, which excessively activates the mast cells or basophils, leading them to release massive amounts of histamines. If both PARENTS have allergies, you have a 70% of having them, if only one parent does, you have a 48% probability.

The correct choice is (c) Histidine decarboxylase

Explanation: Histamine, when released, causes inflammation by INCREASING vasodilation, capillary permeability, CAUSING smooth MUSCLE contraction, mucus secretion, and parasympathetic nerve stimulation. Occurs primarily in mast cells and basophils.

Right option is (c) 70%

To elaborate: If both parents have allergies, you have a 70% of having them, if only one parent does, you have a 48% probability. Allergies can be inherited both from MOTHER and father. If the allergy is caused by any defect in Y CHROMOSOME then only having a boy baby will have an allergy.

Right choice is (a) IgE

To explain I would SAY: Allergies are caused by a hypersensitivity reaction of the ANTIBODY class IgE which are located on mast CELLS in the tissues and basophils in the blood. When an allergen is encountered, it binds to IgE, which excessively activates the mast cells or basophils, leading them to release massive amounts of histamines. These histamines lead to inflammatory responses RANGING from a RUNNY nose to anaphylactic shock.

Correct choice is (a) H1 receptor antagonist

For EXPLANATION: A drug that reduces or eliminates the effects mediated by the chemical histamine. True antihistamines produce a therapeutic EFFECT which will be mediated by negative MODULATION of histamine receptors. The term antihistamine only refers to H1 receptor antagonists. Antihistamines compete with histamine for BINDING sites at the receptors. Antihistamine cannot remove the histamine if it is already bound.

Right option is (a) True

The BEST I can EXPLAIN: The given statement is COMPLETELY true. Accumulation of any drug OCCURS because the previous amount of drug was not being completely removed from the body. As the amount of drug in the body rises due to accumulation, the rate of elimination also rises proportionally until a steady-state or plateau is reached when the rate of drug entry into the body equals the rate of EXIT.

Right ANSWER is (a) True

The explanation is: NEONATES, infants and children require different dosages than adults because differences in body surface AREA, TBW, and extracellular fluid volume PER kg body weight basis. The DOSE for such patients are calculated on the basis of the surface area of the babies not the body weight basis because surface area correlates better with dosage requirement, cardiac output, renal blood flow and glomerular filtration in children.

Correct choice is (c) Digoxin

The explanation: For drugs such as digoxin which do not distribute in the excess body space, the VOLUME of distribution do not CHANGE and hence DOSE for administration to a patient should calculated on the basis of ideal body weight. For polar drugs for e.g. antibiotics which distribute in excess body space of obese patients to an extent less than that in lean tissues. Drugs such as caffeine, theophylline, LIDOCAINE and lorazepam gets DISTRIBUTED in same extent in both lean and adipose tissues.

The correct answer is (d) Antibiotics

The explanation: For polar drugs for e.g. antibiotics which distribute in excess body space of obese patients to an extent less than that in LEAN tissues. Thus, the dose should be lesser on per kg TOTAL body WEIGHT basis but more than that on IBW basis. Drugs such as caffeine, theophylline, lidocaine and LORAZEPAM get distributed in same extent in both lean and adipose tissues. For drugs such as DIGOXIN which do not distribute in the excess body space, the volume of distribution does not change and hence dose for administration to a patient should be calculated on the basis of ideal body weight.

The correct choice is (a) 50 KG +- 1kg/2.5cm above or below 150 cm in HEIGHT

For explanation: The volume of distribution of DRUG gets affected by the changes in body WEIGHT. Since increase in the body weight is directly related to the volume of various fluids. The ideal body weight of a man can be calculated by 50 kg +- 1kg/2.5cm above or below 150 cm in height and for woman 45 kg +- 1kg/2.5cm above or below 150 cm in height. Any person whose body weight is more than 25% and above the IBW is considered to be obese.

Correct answer is (b) 45 kg +- 1kg/2.5cm above or below 150 cm in height

For EXPLANATION: The volume of distribution of drug gets affected by the changes in body weight. INCREASE in the body weight is directly related to the volume of various fluids. The ideal body weight for WOMAN 45 kg +- 1kg/2.5cm above or below 150 cm in height. Any person whose body weight is more than 25% and above the IBW is CONSIDERED to be obese.

The correct choice is (a) Cmax/Cmin

The BEST I can explain: Fluctuation is defined as the ratio between Cmax and Cmin. Greater the ratio greater fluctuations will be seen in the graph. Fluctuations depend upon the dosing frequency and half-life of the DRUG. It also depends upon the rate of absorption. Greatest fluctuation can be seen when the drug is ADMINISTERED as a i.v. BOLUS.

Correct answer is (b) Half-life of the drug

To ELABORATE: Any dose frequency is being calculated on the BASIS of half-life of the drug. If the interval is increased without changing the dose, Cmax, Cmin, Cav decreases but the ratio of Cmax/Cmin increases. Opposite can be observed if DOSING interval is REDUCED frequency increased. It can also result in ACCUMULATION and toxicity.

Right OPTION is (c) The manner in which a drug is taken

To ELABORATE: Drug regimen is defined as the manner in which a drug is taken. For some of the drugs such as hypnotics, antiemetics, analgesics, ETC., a single dose is ENOUGH to provide its effective treatment on the patient. But for some of the diseases such as cholera, typhoid, the dosage of the drug has to be calculated and GIVEN for a longer amount of time. In these cases, drugs are to be taken on a repitative basis over a period of time.

Correct choice is (a) LARGER DOSE

Easiest explanation: The marked curve is the curve SHOWING larger dose profile. Greater the dose, greater the fluctuations during each dosing interval and greater the chances of toxicity. The GRAPH shows both therapeutic and TOXIC responses. The curve in the middle is for optimum dose profile. The curve below that is for smaller dose profile.

Correct choice is (c) Cyclizine

For explanation: Ethylenediamine has mepyramine in its class. DIPHENHYDRAMINE is of ethanolamine class. CHLORPHENAMINE is of alkylamine class. Cyclizine is of piperazines class, structurally related to the ethylenediamines and the ethanolamines and thus produces SIGNIFICANT anticholinergic effects. Used most OFTEN to treat motion sickness, vertigo, NAUSEA, and vomiting.

Correct choice is (b) Dosage which MAINTAINS the plasma CONCENTRATION within the therapeutic window.

The explanation: When the drug is administered in suitable doses with SUFFICIENT frequency to ensure that a stable plasma concentration is maintained which will be within the therapeutic window for the entire duration of therapy is KNOWN as OPTIMAL multiple dosage regimen. Drugs such as antibiotics a minimum effective concentration has to be maintained for all time till the patient heals.

The correct option is (d) Lack of selectivity of H1 receptor, anticholinergic effect, and CNS depression

To explain: Associated with the first generation H1-antihistamines and due to their lack of selectivity for the H1 receptor and anticholinergic activity. Side effects are due to CNS depression are sedation, DIZZINESS, tinnitus, blurred vision, euphoria, INCOORDINATION, anxiety, INSOMNIA, tremor, nausea/vomiting. DRY mouth/dry cough, Newer second-generation H1-antihistamines are more selective for the peripheral histamine RECEPTORS and have far fewer side effects.

Right option is (a) Phenytoin

To explain I would say: Drugs such as phenytoin, diazepam, and thiopental are lipid soluble, these drugs GET distributed to the adipose tissue more, and thus increases the volume of distribution. In obese patients’ volume of distribution is LARGER per KG body WEIGHT and thus requires larger doses more than TOTAL body weight basis.

Right choice is (b) Loop diuretics

The explanation is: For hypercalcemia patients we can USE loop diuretics. Loop diuretics act directly on the ascending limb of the loop of Henle to INHIBIT sodium and chloride RESORPTION. Edema associated with hepatic or renal disease, control of hypertension, increase renal excretion of calcium in patients with hypercalcemia, useful when rapid diuresis is desired because of the rapid ONSET of action.

The correct choice is (c) Hepatic cirrhosis

For EXPLANATION I would say: THIAZIDE and thiazide-like diuretics are mostly prescribed for hypertension, idiopathic hypercalciuria, and treatment of hepatic cirrhosis. Loop diuretics ACT directly on the ascending limb of the loop of Henle to inhibit sodium and CHLORIDE resorption. Carbonic anhydrous inhibitors are used with miotics to lower intraocular pressure before OCULAR surgery in certain cases.

Correct answer is (c) Ascending loop of Henle

Explanation: Loop DIURETICS act on the ascending limb of the loop of Henle to inhibit sodium and chloride resorption. These ALSO INCREASE renal prostaglandins, resulting in the dilation of blood vessels and reduced peripheral VASCULAR resistance. These CAUSE loss of water reduces blood pressure, reduced pulmonary vascular resistance, reduced systemic vascular resistance and central venous pressure.

The correct choice is (b) False

To EXPLAIN I would say: A drug that reduces or eliminates the effects mediated by the chemical histamine. True antihistamines are only the agents that PRODUCE a therapeutic effect that is mediated by negative modulation of histamine receptors. The term antihistamine only refers to H1 receptor antagonists. Antihistamines compete with histamine for BINDING sites at the receptors. Antihistamine cannot remove the histamine if it is ALREADY BOUND.