Pharmacology Test with Answers: 50 Questions for Exam Preparation

Diazepam enhances GABAergic inhibition in the central nervous system, effectively managing seizures caused by the blockade of inhibitory glycine receptors.

Venomous substances (List A) and potent substances (List B) have a narrow therapeutic index; therefore, their prescribing and dosing are strictly regulated by law to prevent severe poisonings.

The apparent volume of distribution is a calculated pharmacokinetic parameter reflecting the hypothetical volume of fluid that would be required to uniformly distribute the administered dose of a drug at a concentration similar to that in the blood plasma.

Tight junctions (zonulae occludentes) form a continuous barrier between epithelial cells, preventing paracellular diffusion of water-soluble molecules.

The insulin receptor belongs to catalytic receptors and possesses intrinsic tyrosine kinase activity. Hormone binding induces receptor autophosphorylation, which triggers a cascade of intracellular reactions.

Direct adrenomimetics bind directly to adrenoceptors, whereas ephedrine acts predominantly indirectly by stimulating the release of endogenous norepinephrine from presynaptic terminals.

Nialamide is a non-selective MAO inhibitor that blocks the breakdown of tyramine in the body. The accumulation of dietary tyramine leads to a massive release of norepinephrine from sympathetic nerve terminals and the development of a severe hypertensive crisis.

Tolerance in the form of receptor desensitization is a universal adaptation mechanism and develops with prolonged agonist exposure to any $\beta$-adrenoceptor subtype.

Indirect-acting sympathomimetics exert their effect by releasing norepinephrine from presynaptic vesicles. Reserpine blocks the vesicular monoamine transporter, depleting neurotransmitter stores, thereby significantly diminishing the action of sympathomimetics.

Reserpine is a sympatholytic agent that readily crosses the blood-brain barrier. Unlike at peripheral terminals where it predominantly depletes norepinephrine stores, in the CNS the drug additionally decreases dopamine and serotonin levels, causing a sedative effect and depression.

Iron therapy is continued for several months after hemoglobin normalization to replenish tissue stores of the trace element, which is monitored via ferritin and serum iron levels.

Oral iron preparations exert a direct irritating and damaging effect on the gastrointestinal mucosa, which can provoke an exacerbation of peptic ulcer disease.

Granulocyte colony-stimulating factor (G-CSF) selectively acts on myeloid progenitor cells, stimulating their proliferation and differentiation primarily into mature neutrophils.

Following subcutaneous injection, recombinant colony-stimulating factor macromolecules are absorbed into the systemic circulation gradually, reaching maximum concentration on average in 3–4 hours.

Liquid iron preparations upon contact with teeth can cause persistent enamel darkening. The use of solid dosage forms (tablets or capsules) prevents direct contact of the active substance with the oral cavity.

Glucocorticoids possess mineralocorticoid activity and promote renal potassium excretion, which, when co-administered with thiazide diuretics, is additive and increases the risk of severe hypokalemia.

Mannitol is practically not absorbed in the gastrointestinal tract, therefore it is administered intravenously to achieve a systemic osmotic diuretic effect.

Potassium-sparing diuretics reduce the secretion of potassium ions into the lumen of the collecting ducts, which, with prolonged use or impaired renal function, naturally leads to potassium retention in the body and the development of hyperkalemia.

Thiazide diuretics, which include hydrochlorothiazide, act in the early part of the distal convoluted tubules by inhibiting sodium and chloride ion symport.

Sodium channel (ENaC) blockade eliminates the electrochemical gradient necessary for potassium secretion into the lumen of the collecting ducts. As a result, potassium is retained in the cells and bloodstream, which underlies the mechanism of action of potassium-sparing diuretics.

Slow calcium channel blockers (L-type) reduce the influx of extracellular calcium into vascular smooth muscle cells, which prevents the formation of the actin-myosin complex and leads to vasodilation.

Corglycon belongs to the group of cardiac glycosides, which have a positive inotropic effect and are used to treat acute heart failure.

Systemic minoxidil is a potent peripheral vasodilator used for severe forms of arterial hypertension refractory to combinations of other drugs.

Centrally acting neurotropic drugs decrease sympathetic tone, leading to a simultaneous reduction in total peripheral vascular resistance and cardiac output. This helps avoid reflex tachycardia characteristic of direct vasodilators.

Agmatine, formed in the body by the decarboxylation of the amino acid arginine, is considered the main endogenous ligand for imidazoline receptors. By binding to I₁ receptors in the brainstem, it is involved in the central regulation of blood pressure.

Flucytosine penetrates the fungal cell and is converted into fluorouracil, which incorporates into RNA and disrupts nucleic acid synthesis, acting as an antimetabolite.

The capsid is a protein shell surrounding the viral genome, whereas the supercapsid (peplos) is an additional external lipid-containing membrane derived from the host cell membranes.

Amphotericin B is a natural polyene antibiotic that binds to ergosterol in the fungal cell membrane, disrupting its permeability. The other drugs are synthetic antifungals (azoles and allylamines).

Allylamines (terbinafine) disrupt an early stage of fungal cell wall ergosterol synthesis by inhibiting squalene epoxidase, whereas azoles block the 14-alpha-demethylase enzyme at a later stage.

In addition to its broad antifungal action, clotrimazole possesses antibacterial activity against certain anaerobes (including Gardnerella) and antiprotozoal activity against Trichomonas vaginalis. This makes it particularly effective in mixed gynecological infections.

Microorganisms possess unique structures (such as a cell wall), which allows for the creation of drugs with high selective toxicity, whereas tumor cells are metabolically similar to the healthy cells of the host organism.

The combined antimalarial drug Fansidar contains the long-acting sulfonamide sulfadoxine and the dihydrofolate reductase inhibitor pyrimethamine.

Pentamidine is the drug of choice for the treatment of the hemolymphatic (early) stage of African trypanosomiasis. The other listed agents are antimonials used in leishmaniasis.

Atovaquone is structurally similar to coenzyme Q (ubiquinone) and competitively inhibits the cytochrome bc1 complex, disrupting plasmodial cellular respiration.

Levamisole is an anthelmintic agent active against nematodes (roundworms). Necatoriasis is caused by roundworms, whereas the other listed conditions are caused by tapeworms or flukes, against which the drug is ineffective.

Ascorbic acid is the international nonproprietary name and chemical designation of vitamin C.

Pellagra develops due to niacin (vitamin B3) deficiency; therefore, nicotinic acid or nicotinamide preparations are used for its specific treatment.

Prostaglandin E₂ is synthesized at the site of inflammation via cyclooxygenase-2, sensitizes pain receptors to the action of bradykinin and histamine, and affects the thermoregulatory center in the hypothalamus, causing fever.

Beta-carotene is a precursor of retinol (vitamin A), the deficiency of which leads to impaired ocular epithelial trophic function and the development of xerophthalmia.

The final stage of active vitamin D (calcitriol) synthesis occurs in the kidneys. When this process is impaired, intestinal calcium absorption decreases, leading to secondary hyperparathyroidism and bone resorption with the development of osteoporosis.

The main pharmacodynamic property of cardiotonic agents is a direct stimulating effect on the contractile myocardium, manifested by a positive inotropic effect and an increase in cardiac output.

Cardiotonic agents are used in both acute (dobutamine, dopamine, levosimendan) and chronic (cardiac glycosides) heart failure to increase the ejection fraction.

Levosimendan has its own vasodilating effect through the opening of ATP-sensitive potassium channels; therefore, its combination with nitric oxide donors can lead to a sharp drop in blood pressure.

Digoxin is a classic cardiotonic agent of plant origin from the cardiac glycoside group. All other listed drugs belong to non-glycoside inotropic agents.

Levosimendan has positive inotropic and vasodilating effects, which can lead to reflex activation of the sympathoadrenal system. This, along with increased myocardial sensitivity to calcium, often causes tachycardia and various arrhythmias.

Douching is a method of vaginal irrigation; therefore, this dosage form of eucalyptus infusion is used exclusively in gynecological practice to treat local inflammatory processes.

Alcohol at a concentration of 70% coagulates proteins of the outer membranes of microorganisms more slowly, allowing it to penetrate deeper into the bacterial cell and exert a more pronounced bactericidal effect than 95% alcohol, which has a rapid superficial tanning effect.

Upon contact with tissues, hydrogen peroxide is cleaved by catalase with the release of molecular oxygen, which has a weak antimicrobial effect compared to atomic oxygen. The main effect of hydrogen peroxide is mechanical wound cleaning through foaming.

Calcium hydroxide creates a pronounced alkaline environment (pH around 12.5), which provides a powerful antibacterial effect in the root canal. In addition, it stimulates odontoblasts to form secondary dentin, promoting dental tissue regeneration.

Hexamethylenetetramine (methenamine) has no intrinsic antimicrobial activity, but at a urine pH below 5.5 it hydrolyzes to release formaldehyde, which denatures bacterial proteins.