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Pharmacology

Terms in this set (75)

Biotransformation process/es of acetaminophen include/s the ff:

A. Acetylation
B. Glucoronidation
C. Glutathione-absorption
D. Glutathione-sulfonylidation
B. Glucoronidation
Which liver enzyme is responsible for the glucoronidation of almost all drugs?

A. UDP
B. GST
C. NAT
D. SULT
A. UDP
A patient has received excessive doses of nitroprusside, and toxic manifestations are developing in response to a metabolite. What kind of toxicity is possible with excessive nitroprusside dosage?

A. Warm Hemolytic Anemia
B. Bleeding
C. Hydroxycobalamin effect
D. Cyanide toxicity
D. Cyanide toxicity
Pharmacologic effect of ACE inhibitors in chronic heart failure is:

A. Decrease preload and afterload
B. Decrease preload, increase afterload
C. Increase preload and afterload
D. Increase preload, decrease afterload
A. Decrease preload and afterload
A 6 months old child undergoing an antibiotic therapy suddenly became hypothermic, and flaccid. The parents also noted that their child has greyed in color. Which of the following drugs could be the cause of this?

A. Vancomycin
B. Amikacin
C. Linezolid
D. Chloramphenicol
D. Chloramphenicol
Which of the following is the drug of choice for prophylaxis and treatment of anthrax?

A. Amoxicillin
B. Ciprofloxacin
C. Rifampicin
D. Nalidixic acid
B. Ciprofloxacin
A 27-year old male currently on anti-tuberculosis treatment suddenly developed hearing loss and vertigo. Which of the following drugs is the most likely culprit?

A. Rifampicin
B. Ethambutol
C. Streptomycin
D. Pyrazinamide
C. Streptomycin
The mechanism of action of this drug is that it binds to the cytoplasmic membrane and forms complexes via calcium-dependent processes and pore development leading to the loss of potassium?

A. Daptomycin
B. Fosfomycin
C. Vancomycin
D. Cyclosporine
A. Daptomycin
Precautions in the use of Sildenafil for
pulmonary hypertension when used in
conjunction with nitrovasodilators would
include

A. Incessant coughing
B. Hypotension
C. Bleeding
D. Diuresis
B. Hypotension

Sildenafil potentiates the action of nitrates used for angina, and severe hypotension and a few myocardial infarctions have been reported in men taking both drugs. (Katzung 14th ed., page 200)
Patient with diabetes mellitus recently given several anti-hypertensive develops coughing. Which drug is the most probable cause of this symptom?

A. Nitroglycerine
B. Enalapril
C. Verapamil
D. Furosemide
B. Enalapril

Other adverse effects common to all ACE inhibitors include acute renal failure (particularly in patients with bilateral renal artery stenosis or stenosis of the renal artery of a solitary kidney), hyperkalemia, dry cough sometimes
accompanied by wheezing, and angioedema. (Katzung 14th ed., page 185)
Hereditary angioedema is best treated with one of these:

A. Diphenhydramine to block histamine 1 receptors
B. Icatibant to block kinin effects on inflammation
C. Meclinertant to block dilation of blood vessels
D. Prednisone to block pro-inflammatory cytokines
B. Icatibant to block kinin effects on inflammation
Hereditary angioedema can be treated with drugs that inhibit the formation or actions of bradykinin (Katzung 14th ed., page 307)
Icatibant has been shown to be effective in the treatment of hereditary angioedema (Katzung 14th ed., page 307)
A 3-year-old is brought to the emergency department having
just ingested a large overdose of tolbutamide, an oral
antidiabetic drug. Tolbutamide is a weak acid with a pKa
of 5.3. It is capable of entering most tissues, including the
brain. On physical examination, the heart rate is 100/min,
blood pressure 90/50 mm Hg, and respiratory rate 20/min.
Which of the following statements about this case of tolbutamide
overdose is most correct?
A. Urinary excretion would be accelerated by administration
of NH4Cl, an acidifying agent
B. Urinary excretion would be accelerated by giving
NaHCO3, an alkalinizing agent
C. Less of the drug would be ionized at blood pH than at
stomach pH
D. Absorption of the drug would be slower from the stomach
than from the small intestine
E. Hemodialysis is the only effective therapy
Questions that deal with acid-base (Henderson-Hasselbalch) manipulations are common on examinations. Since absorption involves permeation across lipid membranes, we can in theory treat an overdose by decreasing absorption from the gut and reabsorption from the tubular urine by making the drug less lipid-soluble. Ionization attracts water molecules and decreases lipid solubility. Tolbutamide is a weak acid, which means that it is less ionized when protonated, ie, at acid pH. Choice C suggests that the drug would be less ionized at pH 7.4 than at pH 2.0, which is clearly wrong for weak acids. Choice D says
(in effect) that the more ionized form is absorbed faster, which is incorrect. A and B are opposites because NH4Cl is an acidifying salt and sodium bicarbonate an alkalinizing one. (From the point of view of test strategy, opposites in a list of answers always deserve careful attention.) E is a distracter. Because an alkaline environment favors ionization of a weak acid, we should give bicarbonate. The answer is B. Note that clinical management of overdose involves many other considerations in addition to trapping the drug in urine; manipulation of urine pH may be contraindicated for other reasons.
Botulinum toxin is a large protein molecule. Its action on
cholinergic transmission depends on an intracellular action
within nerve endings. Which one of the following processes
is best suited for permeation of very large protein molecules
into cells?
(A) Aqueous diffusion
(B) Endocytosis
(C) First-pass effect
(D) Lipid diffusion
(E) Special carrier transport
Endocytosis is an important mechanism for transport of
very large molecules across membranes. Aqueous diffusion is not involved in transport across the lipid barrier of cell membranes. Lipid diffusion and special carrier transport are common for smaller molecules. The first-pass effect has nothing to do with the mechanisms of permeation; rather, it denotes drug metabolism or excretion before absorption into the systemic circulation. The answer is B.
A 12-year-old child has bacterial pharyngitis and is to receive
an oral antibiotic. She complains of a sore throat and pain on
swallowing. The tympanic membranes are slightly reddened
bilaterally, but she does not complain of earache. Blood pressure
is 105/70 mm Hg, heart rate 100/mm, temperature
37.8 °C (100.1 °F). Ampicillin is a weak organic acid with
a pKa of 2.5. What percentage of a given dose will be in the
lipid-soluble form in the duodenum at a pH of 4.5?
(A) About 1%
(B) About 10%
(C) About 50%
(D) About 90%
(E) About 99%
In this question, the emphasis is clearly on pharmacokinetic principles. Ampicillin is an acid, so it is more ionized at alkaline pH and less ionized at acidic pH. The Henderson-Hasselbalch equation predicts that the ratio changes from 50/50 at the pH equal to the pKa to 1/10 (protonated/unprotonated) at 1 pH unit more alkaline than the pKa and 1/100 at 2 pH units more alkaline. For acids, the protonated form is the nonionized, more lipid-soluble form. The answer is A.
Ampicillin is eliminated by first-order kinetics. Which of the
following statements best describes the process by which the
plasma concentration of this drug declines?
(A) There is only 1 metabolic path for drug elimination
(B) The half-life is the same regardless of the plasma
concentration
(C) The drug is largely metabolized in the liver after oral
administration and has low bioavailability
(D) The rate of elimination is proportional to the rate of
administration at all times
(E) The drug is distributed to only 1 compartment outside
the vascular system
"First-order" means that the elimination rate is proportional to the concentration perfusing the organ of elimination. The half-life is a constant. The rate of elimination is proportional to the rate of administration only at steady state. The order of elimination is independent of the number of compartments into which a drug distributes. The answer is B.
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