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