Question 1

Low molecular weight heparins differ from unfractionated heparin in that:

Accepted Answer

Low molecular weight heparins (LMWHs) have several differences from unfractionated heparin (UFH), including selective inhibition of factor Xa, less significant prolongation of clotting time, and a slower metabolism leading to a longer duration of action.

Question 2

Low molecular weight heparins have the following advantages over unfractionated heparin except:

Accepted Answer

Low molecular weight heparins (LMWHs) do not have a higher efficacy in arterial thrombosis compared to unfractionated heparin (UFH); their main advantages include less frequent dosing, higher and more consistent subcutaneous bioavailability, and the reduced need for laboratory monitoring of their anticoagulant effect.

Question 3

Choose the drug of which IUPAC name is 1,1-dimethylbiguanide.

Accepted Answer

Metformin's IUPAC name is 1,1-dimethylbiguanide, which classifies it as a biguanide medication primarily used for the treatment of type 2 diabetes.

Question 4

Which fibrinolytic agent(s) selectively activate(s) fibrin bound plasminogen rather than circulating plasminogen:

Accepted Answer

Alteplase selectively activates fibrin-bound plasminogen, which allows for targeted fibrinolysis, minimizing systemic effects.

Question 5

The most important complication of streptokinase therapy is:

Accepted Answer

Bleeding is the most important and serious complication of streptokinase therapy because streptokinase acts by dissolving blood clots, which can lead to an increased risk of bleeding.

Question 6

Aspirin prolongs bleeding time by inhibiting the synthesis of:

Accepted Answer

Aspirin inhibits the enzyme cyclooxygenase, which is necessary for the synthesis of thromboxane A2 in platelets. Thromboxane A2 is a molecule that promotes platelet aggregation and vasoconstriction, thus playing a key role in the formation of blood clots. By inhibiting its synthesis, aspirin prolongs bleeding time.

Question 7

The following is true of clopidogrel except:

Accepted Answer

Clopidogrel is not a GPIIb/IIIa receptor antagonist; it is a P2Y12 adenosine diphosphate (ADP) receptor inhibitor that prevents platelet activation and aggregation. GPIIb/IIIa receptor antagonists are a different class of antiplatelet drugs.

Question 8

Choose the most potent and most efficacious LDL cholesterol lowering HMG-CoA reductase inhibitor:

Accepted Answer

Atorvastatin is known to be the most potent and efficacious LDL cholesterol-lowering agent among the HMG-CoA reductase inhibitors listed, due to its higher potency in inhibiting the enzyme responsible for cholesterol synthesis.

Question 9

Select the most appropriate hypolipidemic drug for a patient with raised LDL-cholesterol level but normal triglyceride level:

Accepted Answer

HMG-CoA reductase inhibitors, also known as statins, are the most effective drugs for lowering LDL-cholesterol levels, which is the primary goal in patients with elevated LDL-cholesterol but normal triglyceride levels.

Question 10

Select the hypolipidemic drug that enhances lipoprotein synthesis, fatty acid oxidation and LDLreceptor expression in liver through paroxisome proliferator-activated receptor ?

Accepted Answer

Bezafibrate is a fibrate drug that acts as an agonist to the peroxisome proliferator-activated receptor (PPAR), which plays a role in enhancing lipoprotein synthesis, fatty acid oxidation, and LDL receptor expression in the liver.

Question 11

Plasma expanders are used in the following conditions except: (Note: They will increase circulating blood volume and thus preload on heart, which will worsen heart failure.)

Accepted Answer

Plasma expanders are used to increase circulating blood volume in conditions like extensive burns, mutilating injuries, and endotoxin shock, but not in congestive heart failure, where increasing preload can worsen the condition.

Question 12

Trapping of iodide by the following organ/organs is enhanced by thyrotropin:

Accepted Answer

Thyrotropin, also known as thyroid-stimulating hormone (TSH), specifically stimulates the thyroid gland to trap iodide, which is a crucial step in the synthesis of thyroid hormones.

Question 13

Triiodothyronine differs from thyroxine in that:

Accepted Answer

Triiodothyronine (T3) has a shorter plasma half-life compared to thyroxine (T4), making it more rapidly metabolized and cleared from the body.

Question 14

The most reliable guide to adjustment of thyroxine dose in a patient of hypothyroidism is:

Accepted Answer

Serum TSH level is the most reliable guide to the adjustment of thyroxine dose in patients with hypothyroidism because it reflects the pituitary's response to the circulating levels of thyroid hormones, providing a sensitive indicator of thyroid function status.

Question 15

Actions of thyroxine include the following except:

Accepted Answer

Thyroxine, a thyroid hormone, generally increases metabolism, which can lead to a rise in blood sugar levels, reduction in plasma cholesterol levels, and induction of a negative nitrogen balance due to increased protein breakdown. However, it does not cause a fall in plasma free fatty acid levels; instead, it can increase lipolysis, leading to a rise in free fatty acids.

Question 16

acts by inhibiting:

Accepted Answer

The correct answer is B) Oxidation of iodide. This is the mechanism of action for certain antithyroid drugs like methimazole and propylthiouracil, which inhibit the enzyme thyroid peroxidase, preventing the oxidation of iodide and subsequent iodination of tyrosine residues in thyroglobulin.

Question 17

Antithyroid drugs exert the following action:

Accepted Answer

Antithyroid drugs primarily work by inhibiting the synthesis of thyroxine (T4) and triiodothyronine (T3) within the thyroid gland.

Question 18

Given structure is of

Accepted Answer

Methimazole is a medication used to treat hyperthyroidism and is characterized by its distinct chemical structure, which differentiates it from propyl thiouracil, carbimazole (which is a prodrug of methimazole), and radioactive iodine, which is not a chemical compound but a treatment method.

Question 19

The following thyroid inhibitor interferes with peripheral conversion of thyroxine to triiodothyronine:

Accepted Answer

Propyl thiouracil not only inhibits the synthesis of thyroid hormones by interfering with the incorporation of iodine into tyrosyl residues of thyroglobulin but also inhibits the peripheral conversion of thyroxine (T4) to the more active form, triiodothyronine (T3). Methimazole and Carbimazole primarily inhibit thyroid hormone synthesis without affecting peripheral conversion, and Radioactive iodine is used to destroy thyroid tissue in hyperthyroid conditions, also not affecting the conversion process.

Question 20

The uses of sodium/potassium iodide include the following except:

Accepted Answer

Sodium/potassium iodide is used in the preoperative preparation of Graves' disease patients, for the prophylaxis of endemic goiter, and as an expectorant. It is not used as an antiseptic; instead, iodine or povidone-iodine solutions are commonly used for their antiseptic properties.

Quiz 4: Pharmacology and Drug Therapy