General Principles

The answer is c. (Hardman, pp 37-38J Based on the concept that, for most situations, the association of a drug with its receptor is reversible, the following reaction applies where D is the concentration of free drug, R is the concentration of receptors, DR is the concentration of drug bound to its receptors, and Kn (equal to k2 k ) is the equilibrium dissociation constant. The affinity of a drug for its receptor is estimated from the dissociation constant in that its reciprocal, 1 Kn, is...

Info

207, Which of the following local anesthetics is useful for topical (surface) administration only 208, Akathisia. Parkinson-like syndrome, galactorrhea, and amenorrhea are side effects of perphenazine, caused by a. Blockade of muscarinic receptors b. Blockade of ot-adrenergic receptors c. Bio ckad e o f do pa m I ti e re c ep t or s d. Supersensitivity of dopamine receptors e. Stimulation of nicotinic receptors 209, Which of the following agents is useful in the treatment of malignant...

Questions E88E89

It is customary today to classify antiarrhythmic drugs according to their mechanism of action. This is best defined by intracellular recordings that yield monophasic action potentials. In the accompanying figure, the monophasic action potentials of (A) slow response fiber (SA node) and (B) fast Purkinje fiber are shown. Tor each description that follows, choose the appropriate drug with which the change in character of the monophasic action potential is likely to be associated 188. Moderate...

Local Control Substances

336, The answer is e, (Katzung pp 280-281.) Sumatriptan is closely related to serotonin (5-1 IT) in structure, and it is believed that the drug is effective in the treatment of acute migraine headaches by virtue of its selective agonistic activity at 5-1 ITlh receptors. These receptors, present on cerebral and meningeal arteries, mediate vasoconstriction induced by 5-1 IT. Ln addition, 5-1 IT m receptors are found on presynaptic nerve terminals and function to inhibit the release of...

Questions 450452

For each inhibitory effect on the synthesis of thyroid hormone listed below, select the agent that causes it. 450, Inhibits, by acting as a competitor the accumulation of 1 in thyroid follicular cells 45 I. Inhibits the peroxidase-catalyzed oxidation of I and, thus, interferes with the incorporation of I into an organic structure 452, Inhibits the peroxidase-catalyzed coupling of iodotyrosines to form 10 do thyronines 453, A 53-year-old female with NIDDM is started on a sulfonylurea. Which of...

Cancer Chemotherapy and Immunology

106, The answer is b, (Hardman pp 1296-1299J Cyclosporins is the preferred agent because it is a specific T cell inhibitor, and its success rate in protecting a gain si rejection is considerably better than that of any other agent. All of the other agents listed in the question are cytotoxic, because of the severe adverse reactions with cyclosporin it is used in conjunction with azathioprine, which reduces the required dose. Prednisone is also used in conjunction with cyclosporine. 107, The...

Anti Infectives

37, The answer is c. (Hardman, p 1179. Katzung, pp 815-816.) Amphotericin B may alter kidney function by decreasing creatinine clearance if this occurs, the dose must be reduced. It also commonly increases potassium (K+) clearance, leading to hypokalemia, and causes anemia and neurologic symptoms. A liposomal preparation may reduce the incidence of renal and neurologic toxicity Vancomycin is less likely to cause kidney damage if it does, the damage is less severe. 38, The answer is c. (Hardman,...

Endocrine System

Anabolic steroids Corticosteroids Male sex hormones Female sex hormones Oral fertility agents Oral hypoglycemics Parathyroid agents Thyroid agents DIRECTIONS Fach item below contains a question or incomplete statement followed by suggested responses. Select the one best response to each question 412, The mechanism of aciiott of etidronate disodium is most likely related a An unusual fonn of phosphorus (P) b Inhibition of both normal and abnormal bone resorption d. Excretion unchanged in the...

Cardiovascular and Pulmonary Systems

136, The answer is d. (I lard man, pp 212-213.) Only isoproterenol will lower mean blood pressure, decrease peripheral vascular resistance, and increase heart rate. Methacholine decreases heart rate as does propranolol. Atropine has no action on peripheral resistance. Norepinephrine causes intense vasoconstriction and raises the mean blood pressure. 137, The answer is c, (Hardman, p 810J Digitalis inhibits Na+ K+-ATPase and, hence, decreases myocyte Na pumping, resulting in a relative reduction...

An tiInfectives

Antibacterial Ant i my cob ac t cria Is Antifungals DIRECTIONS Each item below contains a question or incomplete statement followed by suggested responses. Select the one best response to each question 37, A 19-year-old male being treated for leukemia develops fever. You give agents that will cover bacterial, viral and fungal infections. Two days later, he develops acute renal failure. Which drug was most likely responsible 38, A 26-year-old female with acquired immunodeficiency syndrome (AIDS)...

And Nutrition

LIistarnine-2 H2 -receptor antagonists Muscarinic receptor antagonists Pro ton.-pump inhibitors Mucosal protective agents Pancreatic replacement enzymes Laxatives Agents for dissolution of gallstones Agents for inflammatory bowel disease Agents for portal system encephalopathy Vitamins DIRECTIONS Each item below contains a question or incomplete statement followed by suggested responses. Select the one best response to each question. 382, Cimetidine slows the metabolism of many drugs because il...