Pharmacology 3 Flashcards
What are some toxic reactions to local anesthetics due to high systemic levels?
Cardiovascular collapse due to myocardial depression, hypotensive shock)
Prilocaine may cause ___ as an adverse effect.
Methemoglobinemia
Local anesthetics act by interfering with the ___ in the neuron.
Sodium transport
In regards to local anesthetics, only the ___ form can penetrate tissue membranes. Inflamed tissue has a lower than normal pH, which decreases the amount of non-ionized form available to penetrate
Non-ionized (or free base form)
True or false… the duration of procaine is longer than that of an equal dose of lidocaine
True
Procaine hydrochloride is metabolized into __ and ___
Diethylaminoethanol
Benzoic acid
Name one short acting anesthetic
Procaine (ester type)
Name three moderate lasting anesthetics
Prilocaine
Mepivicaine (carbocaine)
Lidocaine
Name three long acting local anesthetics
Bupivicaine (marcaine)
Tetracaine
Etidocaine
The duration of action of lidocaine could be increased with the presence of what medication? Why?
Propranolol
Propranolol slows down the heart via beta receptor blockade, thus blood deliver (and lidocaine) to the liver is reduced.
Propranolol and lidocaine also compete for the same enzyme in the liver thus metabolism of lidocaine can be reduced
Methemoglobinemia may result from a toluidine metabolite of the local anesthetic ___, called ___.
Prilocaine
Orthotoluidine
True or false… high plasma levels of local anesthetics may cause depression of inhibitory neurons in the CNS which could result in respiratory depression and death
True
If you inject lidocaine intraoral-arterially, what would likely be the first sign of lidocaine toxicity?
CNS excitation
Initially LAs inhibit central inhibitory neurons, which results in CNS stimulation, which can proceed to convulsions. At higher doses, they inhibit both inhibitory and excitatory neurons, leading to a generalized state of CNS depression which can result in respiratory depression and death
How is a patient with Grave’s disease more sensitive to epinephrine in local anesthetic?
Grave’s disease is an autoimmune disease that causes hyperthyroidism - the resulting high levels of circulating thyroid hormone result in hypermetabolic state with heightened sympathetic activity, which combined with injected epinephrine could result in a hypertensive crisis.
Cardiovascular collapse elicited by a high circulating dose of a local anesthetic may be caused by ____
Myocardial depression
LA’s in toxic doses depress membrane excitability and conduction velocity
What is the most serious consequence of local anesthetic toxicity?
Postconvulsive CNS depression
Local anesthetics block nerve conduction by…
Preventing an increase in membrane permeability to Na+
Only the __ form of LAs can pass through the membrane. Once inside the membrane only the ___ is effective in affecting the __ channel.
Nonionized (free base)
Ionized
Sodium
Most local anesthetics are weak [acids/bases] with a pKa ranging from __-__.
Bases
7.5 - 9.5
True or false… the greater the drug concentration, the faster the onset and the greater the degree of effect
True
True or false… local anesthetics block only myelinated nerve fibers at the nodes of ranvier
True
True or false… the larger the diameter of the nerve fiber, the faster the onset of effect
False… the smaller the diameter the faster the onset
True or false… the faster the penetrance of the drug the faster the onset of effect.
True
1:100,000 epinephrine = ___mg/ml
0.01 mg/ml
What is the maximum amount of epinephrine that can be given to a patient with cardiovascular disease? What about a normal, healthy patient?
- 04mg
0. 2mg
1:200,000 = ___mg/ml
0.005 mg/ml
Which is more sensitive to acid degradation, penicillin V or penicillin G?
Penicillin G - thus it should be injected instead of taken orally
Which penicillin has the best gram-negative spectrum?
Ampicillin
Which two drugs are common to have cross-allergenicity with penicillin?
Cephalosporins and ampicillin
Note that erythromycin isn’t
Which penicillin is useful against penicilliniase-producing bugs such as staphylococcus?
Dicloxacillin (Also nafcillin and methicillin)
What penicillin is specifically used for pseudomonas infections?
An extended spectrum such as carbenicillin
What is to be used for prophylaxis for the patient with a prosthetic joint?
Keflex, 2g PO 1 hr before treatment
Name 3 cardiovascular conditions that require antibiotic prophylaxis
Prosthetic valves
Previous endocarditis
Pulmonary shunts
Name 3 cardiovascular conditions that do not need antibiotic prophylaxis
Pacemaker
Rheumatic fever without valvular dysfunction
Mitral valve prolapse without valvular regurgitation
Antifungals such as nystatin bone to ___ in fungal cell walls to weaken the wall
Ergosterol
What are some symptoms seen during allergic reactions to penicillins?
Dermatitis
Stomatitis
Bronchoconstriction
Cardiovascular collapse
What agent produces GI sunset and pseudomonas colitis?
Clindamycin
Aplastic anemia is associated with with antibiotic?
Chloramphenicol
Liver damage or hepatotoxcitity is associated with which antibiotic?
Tetracycline
Erythromycin estolate is assocaited wit allergic ___
Cholestatic hepatitis
True or false… tetracycline and penicillin (cidal-static interaction) cancel each other out due to opposing mechanisms of action
True
___ alters the rate of renal clearance of penicillin
Probenecid
Effectiveness of tetracyclines is reduced by concurrent ingestion of __ or ___
Antacids
Dairy products
Broad spectrum antibiotics enhance the action of coumarin anticoagulants because of the reduction of ___ sources
Vitamin K
Antibiotics such as __ decrease the effectiveness of oral contraceptives due to suppression of normal GI flora involved in the recycling of active steroids from bile conjugates, leading to more rapid excretion of __ from the body
Ampicillin
Steroids
Macrolides such as erythromycin inhibit the metabolism of drugs such as ___ and ___
Seldane
Digoxin
___ or ___ are systemic-acting antifungals useful for treating candidiasis
Fluconazole
Ketoconazole
Are anaphylactic reactions to penicillin more likely to occur when the drug is administered orally or parenterally?
Parenterally
What form of penicillin has the broadest gram-negative spectrum?
Ampicillin
What bactericidal antibiotic is used specifically in the treatment of infections caused by pseudomonas species and indole-positive proteus species?
Carbenicillin
Which antibiotic is able to achieve a higher concentration in bone than in serum, making it useful in treating bone infections such as osteomyelitis?
Clindamycin