Pharmacology Flashcards
Which of the following steroids, when applied topically, is LEAST likely to cause in increase in intraocular pressure (IOP) and why?
Loteprednol; because it is a ketone-based steroid
Prednisolone acetate; because it is an ester-based steroid
Loteprednol; because it is an ester-based steroid
Dexamethasone; because it is an ester-based steroid
Dexamethasone; because it a ketone-based steroid
Prednisolone acetate; because it is a ketone-based steroid
Loteprednol; because it is an ester-based steroid
Explanation
If a topical steroid is indicated in a patient who has a history of steroid-induced ocular hypertension or glaucoma, it is often sufficient to prescribe a weaker steroid (such as loteprednol) to control the signs and symptoms of an inflammatory reaction. Loteprednol is an ester-based corticosteroid, which tends to cause less pressure elevation for a given amount of anti-inflammatory effect in comparison to ketone-based steroids (dexamethasone and prednisolone). If intraocular pressure is a persistent issue even with the use of a weaker steroid, the elevated IOP should then be treated in the same fashion as POAG, with anti-glaucoma medications, remembering to be cautious in prescribing a prostaglandin analog in the presence of ocular inflammation.
Which of the following compounds may be added to amoxicillin to increase its effectiveness against bacteria that have demonstrated resistance to penicillin?
Clavulanic potassium Etabonate Dichromic acid Hydrochloride Chlorthalidone
Clavulanic potassium
Explanation
Augmentin is resistant to beta-lactamase because it is comprised of amoxicillin and clavulanic potassium, which is a potassium salt of clavulanic acid. Clavulanic potassium is a compound that inhibits the enzyme beta-lactamase which can break down the beta-lactam ring of amoxicillin, allowing amoxicillin to maintain its effectiveness in destroying the targeted bacteria.
Which 3 of the following drug-based factors allow for a better ability of the medication to pass through plasma membranes? (Select 3)
Lipid-soluble Smaller molecular structure Water-soluble Ionized Non-ionized Larger molecular structure
Lipid-soluble
Smaller molecular structure
Non-ionized
Explanation
Lipid-soluble drugs that are composed of smaller molecular structure and which are non-ionized possess a better ability to pass through plasma membranes.
Drug-based factors that can affect the absorption of medications through tissues and membranes include formulation, molecular weight, ionization, solubility, etc.
Which of the following topical antibiotic agents is considered to be the safest to use during pregnancy?
Moxifloxacin Erythromycin Gentamicin Tobramycin Ofloxacin Trimethoprim/polymyxin B
Erythromycin
Explanation
Erythromycin is the only topical antibiotic medication that is considered safe to use during pregnancy.
All other topical antibiotics should be used with caution in pregnant or lactating women.
Which of the following anesthetics is used in combination with sodium fluorescein in the topical anesthetic known as Fluress®?
Bupivicaine Benoxinate Tetracaine Benzocaine Proparacaine
Benoxinate
Explanation
Fluress® is a topical anesthetic agent commonly used in the measurement of intraocular pressure using Goldmann applanation tonometry. It is a combination of 0.4% benoxinate hydrochloride and 0.25% sodium fluorescein.
A medication whose mechanism of action results in inhibiting or arresting the growth, development, or multiplication of an infecting bacteria is known as which of the following?
Bacteriostatic
Bactericidal
Virucidal
Virustatic
Bacteriostatic
Explanation
Bacteriostatic: Antibiotics whose mechanism of action is to inhibit or arrest the growth, development, or multiplication of the infecting bacteria
Bactericidal: Antibiotics whose mechanism of action results in bacterial cell death
Virustatic/Virucidal: These terms are not typically used; antiviral is most appropriate as outright eradication of the infecting virus is sometimes not possible
Which of the following classes of medication has a mechanism of action that interferes with the synthesis of folic acid by inhibiting the enzyme that is necessary for incorporating PABA (para-aminobenzoic acid) into dihydrofolic acid?
Macrolides Fluoroquinolones Sulfonamides Penicillins Tetracyclines
Sulfonamides
Explanation
Sulfa antibiotics are structural analogs of PABA (para-aminobenzoic acid) and they competitively inhibit the bacterial enzyme dihydropteroate synthetase which is necessary to convert PABA into dihydrofolic acid. Dihydrofolic acid is the folic acid precursor. Inhibiting folic acid formation will result in the bacteria not being able to synthesize amino acids and DNA.
Which of the following systemic antihistamines are considered sedating?
Desloratadine
Fexofenadine
Chlorpheniramine
Loratadine
Chlorpheniramine
Explanation
Sedating antihistamines:
Diphenhydramine (Benadryl®), chlorpheniramine (ChlroTrimeton®), promethazine (Phenergan®), hydroxyzine (Atarax®),
Non-sedating antihistamines:
Fexofenadine (Allegra®), Loratadine (Claritin®), Desloratadine (Clarinex®), Cetirizine (Zyrtec®)
Which 2 of the following medications are classified as aminoglycosides? (Select 2)
Erythromycin Gentamicin Tobramycin Trimethoprim Ofloxacin Azithromycin
Gentamicin
Tobramycin
Explanation Aminoglycosides are antibiotic agents with a mechanism of action that inhibits protein synthesis by binding to the 30-S ribosomal subunit. Ophthalmic aminoglycosides include gentamycin, tobramycin, and neomycin. Azithromycin and erythromycin are macrolides. Trimethoprim is a folic acid inhibitor and is commonly used in combination with sulfamethoxazole due to their synergistic effects. Ofloxacin is in the fluoroquinolone class of antibiotics.
What is the correct mechanism of action employed by macrolides that enables them to be strong antimicrobial agents?
Inhibition of bacterial DNA gyrase via topoisomerase VI
Interruption of protein synthesis via binding to 50S ribosomal subunit
Inhibition of bacterial DNA gyrase via topoisomerase IV
Inhibition of nucleic acid synthesis and replication
Interruption of protein synthesis via binding to 30S ribosomal subunit
Inhibition of cell wall synthesis resulting in cell wall lysis
Interruption of protein synthesis via binding to 50S ribosomal subunit
Explanation Erythromycin and azithromycin belong to a class of drugs called macrolides. Macrolides are effective antibiotics because they bind to the 50S subunit of bacterial ribosomes, thus interfering with bacterial protein synthesis. Tetracycline and doxycycline are classified as tetracyclines. This class of drugs also interferes with protein synthesis via binding to the 30S ribosomal subunit. Amoxicillin, cloxacillin, dicloxacillin are common anti-bacterials belonging to a class of drugs termed penicillins. Penicillins disrupt cell wall synthesis, making them valuable and widely used antibiotics. Tobramycin, gentamicin and neomycin are categorized as aminoglycosides, which serve as antimicrobials via two mechanisms; aminoglycosides inhibit bacterial protein synthesis as well as create openings in bacterial cell membranes, allowing for increased antibiotic uptake.
Which of the following medications is considered a synthetic version of the thyroid hormone, T4, and is used in the treatment of hypothyroidism?
Levothyroxine Pioglitazone Glyburide Methimazole Propylthiouracil
Levothyroxine
Explanation
Levothyroxine (Synthroid®) is the drug of choice in the treatment of hypothyroidism. It is considered a synthetic version of the thyroid hormone, thyroxine (T4), which is then converted in the peripheral tissues to T3 (tri-iodothyronine).
Propylthiouracil and methimazole (Topazole®) are used in the treatment of hyperthyroidism. They inhibit the synthesis of thyroid hormone within the thyroid gland.
Pioglitazone (Actos®) and Glyburide (Diabeta®/Micronase®) are medications used to treat diabetes.
What is the maximum amount of days that trifluridine 1% ophthalmic solution (Viroptic®) should be used in order to avoid potential ocular toxicity?
10 days 7 days 14 days 21 days 30 days
21 days
Explanation
For adults, adolescents, and children ages 6 or older, the dosage of trifluridine (Viroptic®) is as follows:
Instill 1 drop into the affected eye(s) every 2 hours during waking hours, up to a maximum daily dosage of 9 drops. Continue until the corneal ulcer has completely re-epithelialized.
Once re-epithelialized, the medication should continue for an additional 7 days with 1 drop every 4 hours while awake with a minimum of 5 drops per day.
If no signs of improvement occur after day 7 of therapy or complete re-epithelialization by day 14 of therapy, another treatment should be considered.
Continuous administration of trifluridine for periods exceeding 21 days should be avoided due to potential ocular toxicity.
Which of the following is a common side effect of albuterol?
Depression Tardive dyskinesia Tremors Glaucoma Bradycardia
Tremors
Explanation
Albuterol is a short-acting beta2-agonist commonly used in the management of asthma. Albuterol administration (typically via inhalation) results in relaxation of bronchial smooth muscle as well as the prevention of bronchoconstriction elements from mast cells. Common side effects include tremors, nausea, tachycardia, hypertension and anxiety, among others.
Which 3 of the following statements are TRUE when comparing topical corticosteroid solutions vs. topical corticosteroid suspensions? (Select 3)
Topical corticosteroid solutions are phosphate-based
Topical corticosteroid solutions have prolonged contact time and higher penetration
Topical corticosteroid suspensions have prolonged contact time and higher penetration
Topical corticosteroid solutions do not require shaking prior to use
Topical corticosteroid suspensions are phosphate-based
Topical corticosteroid suspensions do not require shaking prior to use
Topical corticosteroid solutions are phosphate-based
Topical corticosteroid suspensions have prolonged contact time and higher penetration
Topical corticosteroid solutions do not require shaking prior to use
Explanation
Topical corticosteroids can be produced as a solution or a suspension. Phosphate-bases (which are water soluble), are marketed as solutions, while acetates are prepared as suspensions.
Solutions do not require shaking prior to instillation to deliver a uniform dose of the active ingredient to the eye (suspensions do require shaking).
An advantage to a suspension is that small particles of the drug persist in the cul-de-sac, which results in prolonged contact time and higher penetration (as compared to solutions). Shaking the bottle suspends the drug particles allowing for a predictable dosing of the drug.
What is the mechanism of action of the medication Montelukast (Singulair®) which is commonly used in chronic asthma prevention and maintenance?
Leukotriene receptor agonist Beta-2 adrenergic antagonist Muscarinic receptor agonist Muscarinic receptor antagonist Beta-2 adrenergic agonist Leukotriene receptor antagonist
Leukotriene receptor antagonist
Explanation
Montelukast (Singulair®) is a leukotriene receptor antagonist that is used in chronic asthma prevention and maintenance.
Salmeterol (Serevent®) is a long-acting beta-2 adrenergic receptor agonist that is used for maintenance in chronic asthma and chronic obstructive pulmonary disease (COPD). Salmeterol should not be used in acute attacks.
Ipratropium (Atrovent®) and Tiotropium (Spiriva®) are muscarinic antagonists that reverse acetylcholine-induced bronchospasm. They are used in the treatment of bronchospasm associated with COPD.
Albuterol (Ventolin®) and Pirbuterol (Maxair®) are shorter-acting beta-2 adrenergic receptor agonists that cause bronchodilation. They are typically used for acute asthma attacks and in the treatment of COPD and emphysema.
