Pharmaco4_Tuft Flashcards
name of esters local anesthesia? (metabolized in plasma and a little in liver)
procaine
tetracaine
cocaine
name of amide local anesthesia? (metabolized in liver)
Lidocaine Prilocaine (methemogolobin) Mepivacaine Bupivacaine (longer action of duration) dibucaine
cause of toxic reaction of LA? (hypersensitivity is rare)
- high systemic level of LA in general
* specific agent prilocain causing methemogolobin
high systemic level of LA in blood causes?
- myocardial depression causing cardiovascular collapse
- hypotensive shock
- inhibit CNS inhibitory neurons so causing CNS stimulation proceeding to convulsion
mechanism of action of LA?
prevent the generation of nerve impulses by interfering with sodium transport into the neuron
which form of LA is effective?
non-ionized free-base form
- how many milligram of lidocaine and epinephrine in one mL of 2% solution?
- how many milligram of lidocaine and epinephrine in 1.8ml carpule?
- 20mg lido and .01 mg epi
* 36mg lido and .018 mg epi
The most serious consequence of systemic local anesthetic toxicity is
a. Vertigo
b. Hypertension
c. Hyperventilation
d. Post depressive central nervous system convulsions
e. Postconvulsive central nervous system depression
Postconvulsive central nervous system depression
Cardiovascular collapse elicited by a high circulating dose of a local anesthetic may be caused by
a. Syncope
b. Vagal stimulation
c. Histamine release
d. Myocardial depression
e. Medullary stimulation
Myocardial depression
High plasma levels of local anesthetics may cause
a. Inhibition of peristalsis
b. stimulation of baroreceptors resulting in severe hypotension
c. Inhibition of the vagus nerve to the heart
d. Depression of inhibitory neurons in the CNS
Depression of inhibitory neurons in the CNS
Hypotensive shock may result from excessive blood levels of each of the following local anesthetics EXCEPT
a. Cocaine
b. Procaine
c. Lidocaine
d. Tetracaine
e. Mepivacaine
Cocaine - it is the only vasoconstrictors
Which of the following anesthetic drugs produces powerful stimulation of the cerebral cortex?
a. Cocaine
b. Procaine
c. Lidocaine
d. Tetracaine
e. Mepivacaine
Cocaine
Which of the following is true regarding the mechanism of action of local anesthetics?
a. Usually maintain the nerve membrane in a state of
hyperpolarization
b. Prevent the generation of a nerve action potential
c. Maintain the nerve membrane in a state of depolarization
d. Prevent increased permeability of the nerve membrane to
potassium ions
e. Interfere with intracellular nerve metabolism
Prevent the generation of a nerve action potential
The penetration of a local anesthetic into nervous tissue is a function of the
a. Length of the central alkyl chain
b. Lipid solubility of the ionized form
c. Lipid solubility of the unionized form
d. Ester linkage between the aromatic nucleus and the alkyl chain
e. Amide linkage between the aromatic nucleus and the alkyl chain
Lipid solubility of the unionized form
A recently introduced local anesthetic agent is claimed by the manufacturer to be several times as potent as procaine. The product is available in 0.05% buffered aqueous solution in 1.8 ml. cartridge. The maximum amount recommended for dental anesthesia over a 4-hour period is 30 mg. The amount is contained in approximately how many cartridges?
a. 1-9
b. 10-18
c. 19-27
d. 28-36
e. Greater than 36
5%=50mg so 0.05%=0.5mg
for 30mg we need 60ml means 33.3 cartridges
so d is the correct answer
difference of penicillins VK and G?
G is injected while Vk is oral (G is sensitive to Acid) so V is more reliable oral absorption
all of the following antibiotics are considered to have a high rate of allergenicity except? • Penicillines • Erythromycin • Sulfonamides • Amphotericin B
Erythromycin
which of the following antibiotics is the substitute of choice for penicillin sensitive patient? • bacitracin • erythromycin • tetracycline • chloramphenicol
erythromycin - spectrum of action of it is much closer to penicillin, others are broader
which of the following penicillins has a broader gram negative spectrum than penicillin G? • Nafcillin • Ampicillin • Cephalexin • Methicillin • Penicillin V
Ampicillin
Which of the following antibiotics should be considered the drug of choice in the treatment of infection caused by a penicillinase-producing staphylococcus? • Neomycin • Ampicillin • Tetracycline • Penicillin V • Dicloxacillin
Dicloxacillin - the only penicillinase resistance listed
Ampicillin is LEAST effective against penicillinase BUT is extended spectrum
Which of the following is a bactericidal antibiotic used specifically in the treatment of infections caused by Pseudomonas species and indole-positive Proteus species? • Ampicillin • Penicillin V • Tetracycline • Dicloxacillin • Carbenicillin
Carbenicillin - an extended spectrum agent while Ampicillin is ineffective
Chlortetracycline acts by interfering with?
• cell wall synthesis
• nuclear acid synthesis
• protein synthesis on bacterial but not mammalian ribosomes
• protein synthesis on mammalian but not bacterial ribosomes
protein synthesis on bacterial but not mammalian ribosomes
The probable mechanism of the bacteriostatic action of sulfonamides
involves
a. Disruption of the cell membrane
b. Coagulation of intracellular proteins
c. Reduction in oxygen utilization by the cells
d. Inhibition of metabolism by binding acetyl groups
e. Competition with para-aminobenzoic acid in folic acid synthesis
Competition with para-aminobenzoic acid in folic acid synthesis
which of the following statements is true regarding streptomycin?
• it is bactericidal
• it has a gram positive spectrum
• it is usually administered orally
• it disrupts bacterial cell membrane
• it is associated with a low incidence of bacterial resistance
it is bactericidal
Tetracycline reduces the effectiveness of concomitantly administered penicillin by
a. Reducing absorption of penicillin
b. Increasing metabolism of penicillin
c. Increasing renal excretion of penicillin
d. Increasing binding of penicillin to serum proteins
e. None of the above
(e) tetracycline is bacteriostatic and would slow the rapid growth of the microbial population that a bactericidal drug such as penicillin needs to be effective, sine only when rapidly dividing are the cells making cell walls
Which of the following antibiotics is most likely to cause liver damage?
a. Streptomycin
b. Penicillin G
c. Tetracycline
d. Cephalosporins
e. Amphotericin B
Tetracycline
(a) streptomycin can damage the eighth nerve, affecting both balance and hearing, but is not associated with liver damage. (b) other than allergic reactions, penicillins are extremely safe, with no effect on the liver. (d) the cephalosporins are chemically related to the penicillins and share their relatively nontoxic nature. (e) amphotericin B, is an antifungal agent that produces such adverse side effects as nephrotoxicity and hypokalemia, but not liver toxicity. Thus (c) is the correct answer. Tetracyclines have been shown to be hepatotoxic following high doses in pregnant patients with a history of renal disease.
Which of the following erythromycins associated with an allergic cholestatic hepatitis?
a. Erythromycin base
b. Erythromycin stearate
c. Erythromycin estolate
d. Erythromycin succinate
Erythromycin estolate
Symptoms that may be characterized as allergic manifestations during penicillin therapy are
a. Deafness, dizziness and acute anemia
b. Crystalluria, nausea, vomiting and anaphylactic shock
c. Oliguria, hematuria, bronchoconstriction and cardiovascular collapse
d. Dermatitis, stomatitis, bronchoconstriction and cardiovascular collapse
Dermatitis, stomatitis, bronchoconstriction and cardiovascular collapse
Aplastic anemia is a serious toxic effect that occurs particularly after a course of treatment with which of the following antibiotics?
a. Penicillin
b. Lincomycin
c. Tetracycline
d. Streptomycin
e. Chloramphenicol
Chloramphenicol
Each of the following is a side effect of prolonged tetracycline hydrochloride therapy EXCEPT:
a. Suprainfection
b. Photosensitivity
c. Vestibular disturbances
d. Discoloration of newly forming teeth
e. Gastrointestinal symptoms (when administered orally)
Vestibular disturbances
a dental patient with a prosthetic heart valve with no drug allergies should receive prophylactically which drugs?
Ampicillin and Gentamicin - the only dental use of Gentamicin - synergistic effect
The action of which of the following drugs will most likely be impaired by concurrent administration of tetracycline?
a. Clarithromycin
b. Erythromycin
c. Sulfonamide
d. Penicillin
e. Lincomycin
Penicillin
Which of the following has the broadest antimicrobial spectrum?
a. Vancomycin (Vancocin )
b. Clindamycin (Cleocin )
c. Erythromycin (Erythrocin )
d. Chlortetracycline (Aureomycin )
e. A third generation cephalosporin
Chlortetracycline (Aureomycin )- remember, tetracyclines are broad spectrum antibiotics effective against both gram-negative and gram-positive cocci and bacilli. Clindamycin has a spectrum of activity similar to erthyromycin and vancomycin, which is less than that of the tetracylines, mainly affecting gram-positive microorganisms. 1st generation cephalosporins are effective against both gram-negative and gram-positive organisms, but the third generation ones have increased activity against gram-negative but greatly decreased activity against gram-positive microorganisms.
Sulfonamides and trimethoprim are synergistic bacteriostatic agents because in bacteria they
a. Both inhibit folic acid synthesis
b. Interfere sequentially with folinic acid production
c. Are both antimetabolites of para-aminobenzoic
d. Are both inhibitors of dihydrofolic acid reductase
e. Are both transformed in vivo into a single active compound
Interfere sequentially with folinic acid production
when broad spectrum antibiotics are administered with coumarin anticoagulants, the anticoagulant action may be?
increased because of reduction of Vit K sources
drugs for angina (insufficient oxygen to meet demands of myocardium)?
- nitroglycerin: direct vasodilatory action on the smooth muscle in the coronary arteries
- propranolol: reduces oxygen demand by preventing chronotropic responces to endogenous epinephrine, emotions and exercise
- calcium channel blockers such as Verapamil
Antiarrhytmics drugs (heart beats irregularly)?
- lidocaine: decrease cardiac excitability - ventricular arrhythmias
- quinidine: increasing the refractory period of cardiac muscle (Supraventricular arrhythmias)
- Verapamil: atrial fibrillation and Supraventricular arrhythmias
- digitalis (used for atrial fibrillation it acts by decreasing the rate of A-V conduction)
hypertension drugs?
- diuretic: decrease the renal absorption of sodium resulting in fluid loss such as furosemide (high ceiling) or thiazides (chlorothiazide)
- beta blocker: propranolol (nonselective beta blocker reduces ccardiac output and inhibits renin secretion) or metoprolol (selective beta1 blocker, reduces cardiac output)
- alpha1 blocker: prazocin- inhibits binding of nerve induced release of NE resulting in vasodilation
- centrally acting adrenergic drugs: methyldopa (acts centrally as a false neurotransmitter stimulating alpha receptors to reduce sympathetic outflow resulting in vasodilation) or clonidine
- neural blockers: guanethidine (reserved for severe hypertension)
- angiotensin converting enzyme inhibitor: Captopril
congestive heart failure drugs?
- digitalis (digoxin): positive inotropic effect increasing the force of contraction of the myocardium
- ACE inhibitor: Captopril
