PACOP - PINK TOXICOLOGY QUESTIONS PDF

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Two dose-response curve response plotted on the same graph showed sigmoid curves having the same slope and height. T curve is located to the right of the A curve. Which of the following statements is/are correct regarding curves A an: I. A is more effective than B II. A is more potent than B III. A ...

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Two dose-response curve response plotted on the same graph showed sigmoid curves having the same slope and height. T curve is located to the right of the A curve. Which of the following statements is/are correct regarding curves A an:

I. II. III. IV. V.

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A is more effective than B A is more potent than B A and B have the same ceiling dose B is the graph produced when A is given with its competitive antagonist B is the graph produced when A is given with its non-competitive antagonist

a. Only I and III are correct b. Only II, III and IV are correct c. Only II and IV are correct d. Only III and V are correct e. Only V is correct Two dose-response curve plotted on the same graph showed sigmoid curves A and B, where A is at the left of the graph with the height greater than B. Which of the following statements is/are correct regarding curves A and B?

I. II. III. IV. V. a. b. c. d. e.

A and B has equal efficacy A and B have equal potency B is a partial agonist of A B is the graph produced when A is given with its competitive antagonist B is the graph produced when A is given with its non-competitive antagonist Only I and III are correct Only II, III and IV are correct Only II and IV are correct Only III and V are correct Only V is correct

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The cumulative number of subjects who display a certain rersponse or effect to a drug is plotted on a graph as shown below. The graph on the left represents beneficial effect while the graph on the right represents toxic effect, what is the therapeutic index of the drug?

a.0.5 b. 1.5 c. 2.5 d.4.0 e. 5.0 An administration of one drug leads to a shift in the log dose-response curve of another drug to the left a range in the maximal efficacy, this is called a. Agonism b. Partial agonism c. Non-competitive antagonism d. Competitive antagonism e. Potentiation The action of this drug is dependent on a colligative property a. Mannitol b. Cocaine c. Reserpine d. Furosemide e. Losartan Whiich of the following drug groups have mechanisms of aaction that involve binding to enzymes as target protiens a. Benzodiazepines b. Barbiturates c. Calcium channel blockers d. Non-steroidal anti-inflammatory agents e. Phenothiazine antipsychotics Voltage-gated ion channels serve as site of actions for drugs such as I. Diltiazem and Nifedipine II. Lidocaine and Procaine III. Captopril and Losartan a. I only b. I and II c. III only d. I and III e. I, II, and III Drugs with mechanism of action that involves Tubulin-binding leading to loss of function of the structural protien include a. Cyclosporine b. Neostigmine c. Colchicine d. Glibenclamide e. Metformin What type of protien is primarily targeted by Digitalis glycosides when they exert their effect on the heart? a. Receptors b. Ion channels

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c. Enzymes d. Transporters e. Structural protiens Which of the following features cahracterize nicotinic, GABA-A, and Glutamate receptors? a. Thay control the movements of ions and out of the cell b. Their action is mediated bysecondary messengers c. They all have excitatory effect on the cell membrane d. They are located on the cytoplasm Which of the following drugs bind to receptors located at the cell membrane? a. Thyroid hormone b. Prednisone c. Estrogen d. Insulin e. Vitamin D Cyclic Adenosine Monophophate (cAMP) is generated as a secondary messenger by the action of the enzyme Adenylyl Cyclase. The substrate for the synthesis of cAMP is a. AMD b. ADP c. ATP d. GTP e. Adenosine Stimulation of Beta-adrenoceptor, a G-protien-linked receptor involves a generation of a secondary messenger known as a. IP3 b. cGTP c. DAG d. cAMP e. Calcium ions What is the mechanism of action of Sildenafil, a drug popularly known as viagra? a. Inhibits phosphodiesterase (PDE) leading to increase cAMP b. Inhibits PDE leading to increase cGMP c. Stimulates adenylyl cyclase leading to increase cAMP d. Stimulates guanylyl cyclase leading to increase cGMP e. Inhibits phosphodiesterase leading to increase cGMP Drugs that activate the phospholipase C-inositol phosphate system such as alpha-adrenergic agonists like phenylephrine primarily cause an increase in the intracellular levels of which ion? a. Calcium b. Magnesium c. Sodium d. Potassium e. Chloride Which of the following stetements characterizes competitive antagonism? a. There is a shift of the agonist log concentration-effect curve to the right and downwards b. There is a shift of the agonist log concentration-effect curve to the right without a change on the slope or amplitude c. There is an exponential relationship between dose ratio and antagonist concentration d. There is no competition for the binding sites e. There is a shift of the agonist log-concentration effect curve to the left without a change in slope and amplitude The minimum dose that produces the maximum achievable response is known as a. Potency b. ED50 c. LD50 d. Ceiling dose e. Minimum effective dose

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18. The medium dose, or the dose of the drug that produces half of the maximum achievable response is called a. Potency d. Ceiling dose b. LD50 e. Binding constant c. Therapeutic index 19. What is described by the equation given as follows: Response=f (EN total . Xa / (Xa + Ka) a. Relationship between occupancy of receptor and the dose of the drug b. Relationship between occupancy of receptor and response to the drug c. Relationship between the dose of the drug and the response to the drug d. Relationship between the number of receptors and the dose of the drug e. Relationship between the response to the drug and the transducer function of the tissues 20. Competitive antagonist of the receptors of Dopamine and Benzodiazepine are expected to produced which effect? a. Reversal of the intrinsic activity of the receptors b. Maintain the consitutive activity of the receptors c. Stimulate the constitutive activity of the receptors d. Stimulate the constitutive activity of the recptorsin the absence of any ligand e. Produce a negative efficacy 21. The PT-INR of a patient with Warfarin has been maintained at 2.5 for the last 3 months. 1 week earlier, the patient was given Phenobarbital. What can be expected with the PT-INR of the patient? a. Increased PT-INR b. Decreased PT-INR c. Maintained PT-INR 22. Phenobarbital when given to a patient on chronic warfarin is classified as a. Pharmacodynamic antagonist b. Pharmacokinetic antagonist c. Physiologic antagonist d. Synergistic agonist e. Additive agonist 23. Digibind which effetively terminates the action of Digitalis glycosides is classified as what type of antagonist? a. Pharmacodynamic antagonist b. Pharmacokinetic antagonist c. Physiologic antagonist d. Chemical antagonist e. Non-competitive antagonist 24. Omeprazole can inhibiy gastric acid secretion induced by Histamine and Acetylcholine. It is thus classified as what type of antagonist? a. Pharmacodynamic antagonist b. Pharmacokinetic antagonist c. Physiologic antagonist d. Chemivall antagonist e. Non-competitive antagonist 25. Which of the following mechanism may explain the development of tolerance to drugs? a. Increase in the quantity of mediators b. Decreased metabolic degradation of the active drug c. Decreased excretion or extrusion of drugs from cells d. Downregulation of receptors e. Inactivation of counterregulatory physiologic response 26. The prerequisite that drugs must be present in aqueous solution for them to be absorbed is true if the drugs are absorbed by which mechanism? I. Passive transport II. Carrier-mediated transport III. Pinocytosis

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a. I only b. I and II c. III only d. I and III e. I, II, and III According to the Fick’s Diffusion Equation, the rate of transport of a drug by passive diffusion is a. Independent of the concentration gradient b. Inversely proportional to the membrane surface area c. Inversele proportional to the membrane thickness d. Inversely proportional to the partition coefficient e. Independent of the diffusion constant of drug Which of the following feature common to all carrier-mediated transport processes? a. Movement is along a concentration gradient b. Involves non-specific binding to carriers c. Can be characterized by allosteric inhibition d. Displays a Michaelis-Menten Kinetics e. Non-energy requiring Which of the following substances may be absorbed significantly by pinocytosis a. Vitamin K b. Cyanocobalamin c. Cardiac glycosides d. Quarternary ammonium compounds e. Inorganic and organic electrolytes 100ml of aqueous solutionof a given drug has a concentration of 25%.50ml of Octanol was added and after equlibration, the concentration of the drug in the aqueous layer was 5%. What is the apparent lipid-water partition coefficient of the drug?> a. 0.2 b. 2 c. 4 d. 6 e. 8 For drugs that are given constant rate, the time to reach steady rate state concentration dependent on a. Rate of administration b. Biologic half-life c. Volume distribution d. Peak plasma concentration achieved e. Amount of the drug in the body A given drug has a biologic half life of 4 hours. How much of the drug will remain in the body 12 hours after a single dose? a. 75% b. 50% c. 25% d. 12.5% e. 6.25% In compartmental analysis of serum drug concentration versus time plots, which of the following findings confirm a one compartment model of drug behavior? a. An AUC above the explorated line that is less than 10% of the total AUC b. An AUC above the explorated line that is less than 5% of the total AUC c. Slope of the last 3 terminal points differing by more than 10% for the slope of the first 3 terminal points d. Slope of the 3 terminal points differing by less than 20% from the slope of the 3 terminal points e. Cmax that is above the line explorated from the terminal points What should be the rate of infusion of Theophylline if the desired plasma concentration is 10ug/mL in a 70 kg patient?Theophylline has a clearance of 0.6mL/minute per kg body weight. a. 6ug/min

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b. 4.2ug/min c. 17ug/min d. 420ug/min e. 1167ug/min A given drug with a half life of 8 hours is being administered at 100mg every 8 hours. What is the amount remaining in the body after 32nd hour, just before administering the next dose? a. 50mg b. 75mg c. 87.5mg d. 93.75mg e. 100mg What is the con centration at steady state of Phenobarbital if the drug is given to a 60kg patient as a 65mg tablet once daily with a bioavailability of 90%? The drug has volume distribution of 0.5liters/KBW and t1/2 of 100hrs a. 0.10mg/L b. 1.50mg/L c. 11.70mg/L d. 22.20mg/L e. 48.20mg/L A 47 year old female diabetic is maintained on Tolbutamide for control of her hyperglycemia. Her fasting blood sugar is maintained at 102mg%. Three days prior to admission, she self-medicated with Indomethacin due to a joint pain. She was admitted at the emergency room unconscious and difficult to arouse. What laboratory finding may be consistent with the history of the patient? a. Capillary blood glucose of 20mg/dL b. Capillary blood glucose of 400mg/dL c. ALT level that is 3x elevated d. ALT level that is 6x elevated e. Platelet level of 100,000/ul A drug molecule does not possess biologic activity by itself but it converted in the body to an active metabolite is called a/an a. Orphan drug b. Prodrug c. Prototype drug d. Parent drug e. Metabolic drug Astemizole and Terfenadine have been withdrawn from the market because of their intrinsic cardiotoxicity. Tha risk of cardiotoxicity is increased with concominant intake of Grapefruit juiceor Erythromycin. The explanation for this interaction is a. Displacemnet from the protien binding of Astemizole or Terfenadine by Grapefruit juice of Erythromycin b. Decreased urinary excretion of Astemizole and Terfenadine c. Inhibtion of the CYP3A4 enzyme by Grapejuice or Erythromycin d. Increased absorption of Astemizole or Terfenadine e. Induction of metabolism of Astemizole and terfenadineby Grapefruit juice or Erythromycin Paients who are poor Debrisoquin metabolizers have decreased activity of which enzyme system a. CYP 1A2 b. CYP 2C9 c. CYP 2D6 d. CYP 2C19 e. CYP 3A4 A patient has been assessed to have poor Debrisoquin metabolizing capability. Which of the following drugs will have an increased likelihood of causing toxicity in this patient? a. Thioridazine b. Amiodarone c. Acetaminophen

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d. Warfarin e. Theophylline What is considered as dominant phase I metaabolic reaction? a. Oxidation b. Reduction c. Hydrolysis d. Glucuronidation e. Acetylation Chloramphenicol when given to a nenonate or premature baby causes cardiovascular collapse manifestin as the so-called “Gray Baby Syndrome” This toxicity in such subsets of the patients is due to what age-related biologic feature? a. Decreased protien binding b. Decreased urinary excretion of the metabolite c. Deficiency of Glucuronosyl acyl transferase d. Increased metabolism by nitro-reduction e. Increased volume of distribution Cimetidine, Ketoconazole, and Allopurinol share a common pharmacokinetic property that predisposes patients taking other drugs concominantly with any of these agents to toxicity. What is this property? a. Inhibition of tubular secretion b. Increased systemic absorption c. Protien binding dsiplacement d. Enzyme induction e. Enzyme inhibition Biotransformation of orally administerd drugs occuring primarily in the liver that reduces the amount of drug finally entering the systemic circulation is often referred to as __________. a. Enterohepatic recirculation b. Gastric emptying c. Elimination d. First-pass effect e. Enzyme induction Charcoal-broiled foods, cruciferous vegetables and omeprazole induce the metabolism of drugs like tomoxifen, acetaminophen, theophylline and warfarin. This effect is due to induction of which CYP isoform? a. CYP1A2 b. CYP2A6 c. CYP2C9 d. CYP2D6 e. CYP4A4 In a patient with hepatic encelopathy, which of the following agents may lead tosevere drug toxicity even when given at usual doses? a. Diazepam b. Oral Neomycin c. Lactulose d. Propanolol e. IV Gentamicin Which of the following features charcterizes the autonomic nervous system a. Single neuron transmission b. Presence of ganglia c. Effects are under volitional control d. Conveys outpus from the CNS to the skeletal muscles e. Terminal neurotransmitter is mainly Serotonin The preganglionic fibers of the sympathetic nervous system originate from which roots? a. Cranial nerves III, VII, IX, X b. Sacral roots S1- S4

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c. Cervical roots C1-C7 d. Thoracolumbar roots What neurotransmitter is released by preganglionic fibers as a response to sympathetic stimulation? a. Acetylcholine b. Norepinephrine c. Epinephrine d. Serotonin e. Dopamine What is the dominant ganglionic receptor found in most sympathetic fibers? a. Alpha-1 b. Alpha-1 c. Beta-1 d. Nicotinic e. Muscarinic What is the neurotransmitter mainly released by postganglionic parasympathetic fibers? a. Acetylcholine b. Norepinephrine c. Epinephrine d. 5-Hydroxyryptamine e. Dopamine Which of the following non-adrenergic, non-cholinergic neurotransmitters is involved in the action of the enteric nervous system? a. ATP b. Dopamine c. GABA d. Glutamate e. Glycine In synaptic neurotransmission, which of the following ions plays a significant role in neurotransmitter release a. Sodium b. Potassium c. Magnesium d. Calcium e. Chloride The primary mechanism of neuro transmitter release is accomplished by what process? a. Diffusion b. Carrier-mediated c. Active transport d. Facilitated transport e. Exocytosis What is the amino acid precursor in the synthesis of catecholamines? a. Phenylalanine b. Glycine c. Tyrosine d. Tryptamine e. Glutamic acid In the biosynthesis of Norepinephrine, what step is considered rate-limiting? a. Active uptake of Tyrosine b. Conversion of tyrosine to dihydroxyphenylalanine c. Conversion of DOPA to dopamine d. Uptake of Dopamine in presynaptic storage vesicles e. Conversion of Norepinephrine to Epinephrine

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58. Which of the following substances exert a negative feedback control on Tyrosine Hydroxylase which serves as the mechanis for moment-to-moment regulation of the rate catecholamine synthesis? a. Dopamine b. Acetylcholine c. DOPA d. Epinephrine e. Norepinephrine 59. Reserpine, an alkaloid from Rauwolfia, can lower the blood pressure and depress the CNS. What enzyme or part of the biosynthetic pathway is inhibited by Reserpine to bring about these effects? a. DOPA decarboxylase b. Storage of catecholamines in the presynaptic vesicles c. Release of Norepinephrine from presynaptic terminals d. MAO enzymes e. Uptake-1 mechanism 60. What is the most important mechansim of termination of effects of released Norepinephrine which is the target of action of tricyclic antidepressants and Cocaine a. Degradation of COMT b. Degradation of MAO c. Sequestration into cells d. Reuptake into the presynaptic terminal e. Binding to presynaptic alpha-2 receptors 61. What is the main final metabolite of Norepinephrine and Epinephrine which when abnormally elevated is often used as a marker for the disease Pheochromocytoma? a. Dihydroxymandelic acid b. 3-Methoxy-4 hydromandelic acid c. 3-Methoxy-4 hydroxyphenylglycol d. 3,4-Dihydroxyphenylglycol e. Normetanephrine 62. Which of the following is an expected respose to alpha-1 adrenoceptor stimulation? a. Uterine smooth muscle relaxation b. Gastrointestinal sphincter constriction c. Ciliary muscle relaxation d. Gastrointestinal wall smoothe muscle contraction e. Platelet aggregation 63. A male patient wishes to purchase an over-the-counter tablet for colds. Which of the following data you gathered during an initial interview of the patient should prevent you from dispensing the medication? I. The patient is currently taking Nifedipine GITTS II. The patient is currently on Tranylcypromine III. The patient is an elderly with history of urinary hesitancy, intermittency, and frequency a. I only b. I and II c. III only d. I and III e. I, II, and III 64. Stimulation of Alpha-1 receptors leads to the formation of important secondary messengers that promote calcium release and activation of protien kinase C. These secondary messengers responsible for the effects of alpha-1 stimulation include which of the following? a. Inositol triphosphate b. Cyclic adenosine monophophate c. Adenosine triphosphate d. Cyclic guanosine monophosphate e. Adenosine diphosphate

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65. In which of the following clincal conditions are the agonists of the alpha-1 adrenoceptors found to be useful? I. Nasal congestion II. Hypotension III. Sympomatic bradycardia a. I only b. I and II c. III only d. I and III e. I, II, and III 66. Which of the following effects can be attributed to alpha-2 receptor stimulation? I. Vasodilation II. Inhibition of catecholamine release III. Vasoconstriction a. I only b. I and II c. III only d. I and III e. I, II, and III 67. A given adrenergic agent induces uterine relaxation and bronchial smooth mus...