Description : The most important factor which governs diffusion of drugs across capillaries other than those in the brain is: A. Blood flow through the capillary B. Lipid solubility of the drug C. pKa value of the drug D. pH of the medium
Last Answer : A. Blood flow through the capillary
Description : The blood-brain barrier, which restricts entry of many drugs into brain, is constituted by: A. P-glycoprotein efflux carriers in brain capillary cells B. Tight junctions between endothelial cells of brain capillaries C. Enzymes present in brain capillary walls D. All of the above
Last Answer : D. All of the above
Description : Which of the following is not true of the blood-brain barrier: A. It is constituted by tight junctions between the endothelial cells of brain capillaries and the glial tissue B. It allows passage ... of highly ionized drugs into the brain D. It regulates passage of substances from brain into blood
Last Answer : D. It regulates passage of substances from brain into blood
Description : The most important factor governing absorption of a drug from intact skin is: A. Molecular weight of the drug B. Site of application C. Lipid solubility of the drug D. Nature of the base used in the formulation
Last Answer : C. Lipid solubility of the drug
Description : The following attribute of a drug tends to reduce its volume of distribution: A. High lipid solubility B. Low ionisation at physiological pH values C. High plasma protein binding D. High tissue binding
Last Answer : C. High plasma protein binding
Description : Glomerular filtration of a drug is affected by its: A. Lipid solubility B. Plasma protein binding C. Degree of ionization D. Rate of tubular secretion
Last Answer : B. Plasma protein binding
Description : If a drug has a constant bioavailability and first order elimination, its maintenance dose rate will be directly proportional to its: A. Volume of distribution B. Plasma protein binding C. Lipid solubility D. Total body clearance
Last Answer : D. Total body clearanc
Description : 3 Diffusion of drugs across cell membrane: A. Is dependent upon metabolic activity of the cell B. Is competitively inhibited by chemically related drugs C. Is affected by extent of ionization of drug molecules D. Exhibits saturation kinetics
Last Answer : C. Is affected by extent of ionization of drug molecules
Description : Biotransformation of drugs is primarily directed to: A. Activate the drug B. Inactivate the drug C. Convert lipid soluble drugs into nonlipid soluble metabolites D. Convert nonlipid soluble drugs into lipid soluble metabolites
Last Answer : C. Convert lipid soluble drugs into nonlipid soluble metabolites
Description : 6 The blood-brain barrier, which restricts entry of many drugs into brain, is constituted by: A. P-glycoprotein efflux carriers in brain capillary cells B. Tight junctions between endothelial cells of brain capillaries C. Enzymes present in brain capillary walls D. All of the above
Description : Marked redistribution is a feature of: A. Highly lipid soluble drugs B. Poorly lipid soluble drugs C. Depot preparations D. Highly plasma protein bound drugs
Last Answer : A. Highly lipid soluble drugs
Description : A nonvolatile, highly lipid soluble drug is metabolized at a rate of 15% per hour. On intravenous injection it produces general anaesthesia for 10 min. Which process is responsible for termination of ... : A. Metabolism in liver B. Plasma protein binding C. Excretion by kidney D. Redistribution
Last Answer : D. Redistribution
Description : Majority of drugs cross biological membranes primarily by: A. Passive diffusion B. Facilitated diffusion C. Active transport D. Pinocytosis
Last Answer : A. Passive diffusion
Description : Weakly acidic drugs: A. Are bound primarily to α1 acid glycoprotein in plasma B. Are excreted faster in alkaline urine C. Are highly ionized in the gastric juice D. Do not cross blood-brain barrier
Last Answer : B. Are excreted faster in alkaline urine
Description : What is true in relation to drug receptors: A. All drugs act through specific receptors B. All drug receptors are located on the surface of the target cells C. Agonists induce a conformational change in the receptor D. Partial agonists have low affinity for the receptor
Last Answer : C. Agonists induce a conformational change in the receptoR
Last Answer : C. Agonists induce a conformational change in the receptor
Description : The anticholinesterase action of edrophonium is short lasting because termination of its action depends on: A. Dissociation and diffusion of the drug from the enzyme B. Hydrolysis of the drug by the enzyme C. Synthesis of fresh enzyme molecules D. A combination of the above three processes
Last Answer : A. Dissociation and diffusion of the drug from the enzyme
Description : The following statement is true in relation to drug toxicity' and poisoning': A. The two terms are synonymous B. When a toxic effect requires specific treatment, it is called poisoning C. ... is called poisoning D. Toxicity is caused by drugs while poisoning is caused by other harmful chemicals
Last Answer : C. A toxic effect which endangers life by markedly affecting vital functions is called poisoning
Description : Tricyclic antidepressants can alter the oral absorption of many drugs by: A. Complexing with the other drug in the intestinal lumen B. Altering gut motility C. Altering gut flora D. Damaging gut mucosa
Last Answer : B. Altering gut motility
Description : Active transport of a substance across biological membranes has the following characteristics except: A. It is specific B. It is pH dependent C. It is saturable D. It requires metabolic energy
Last Answer : B. It is pH dependent
Description : The pharmacokinetics of drugs in the neonate differs from that in adults, because their: A. Intestinal transit is fast B. Drug metabolizing enzymes are overactive C. Tubular transport mechanisms are not well developed D. Glomerular filtration rate is high
Last Answer : C. Tubular transport mechanisms are not well developed
Description : Compared to the drug named within parenthesis, which of the following drugs has a higher potency but lower efficacy: A. Pethidine (morphine) B. Furosemide (hydrochlorothiazide) C. Diazepam (pentobarbitone) D. Enalapril (captopril)
Last Answer : C. Diazepam (pentobarbitone)
Description : Study of drug-receptor interaction has now shown that: A. Maximal response occurs only when all receptors are occupied by the drug B. Drugs exert an all or none' action on a ... lock and key' structural features D. Properties of affinity' and intrinsic activity' are independently variable
Last Answer : D. Properties of ‘affinity’ and ‘intrinsic activity’ are independently variable
Description : A prodrug is: A. The prototype member of a class of drugs B. The oldest member of a class of drugs C. An inactive drug that is transformed in the body to an active metabolite D. A drug that is stored in body tissues and is then gradually released in the circulation
Last Answer : C. An inactive drug that is transformed in the body to an active metabolite
Description : Monitoring plasma drug concentration is useful while using: A. Antihypertensive drugs B. Levodopa C. Lithium carbonate D. MAO inhibitors
Last Answer : C. Lithium carbonate
Description : Which of the following cytochrome P450 isoenzymes is involved in the metabolism of largest number of drugs in human beings and has been implicated in some dangerous drug interactions: A. CYP 3A4 B. CYP 2C9 C. CYP 2E1 D. CYP 1A2
Last Answer : A. CYP 3A4
Description : The following statement is not correct for uremic patients: A. Attainment of steady-state plasma concentration of drugs eliminated through the kidney is hastened B. Pethidine can cause seizures C. Diazepam produces exaggerated CNS depression D. Tetracyclines further raise blood urea level
Last Answer : A. Attainment of steady-state plasma concentration of drugs eliminated through the kidney is hastened
Description : If the clearance of a drug remains constant, doubling the dose rate will increase the steady-state plasma drug concentration by a factor of: A. × 3 B. × 2 C. × 1.5 D. × 1.3
Last Answer : B. × 2