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
Which antibiotic is able to achieve a higher concentration in gingival crevicular fluid than in serum?
Tetracycline
How does tetracycline reduce the effectiveness of concomitantly administered penicillin?
Tetracycline is bacteriostatic and would slow the rapid growth of the microbial population that a bactericidal drug such as penicillin needs to be effective. Since only when rapidly dividing are the cells making cell walls
Name four side effects of prolonged tetracycline hydrochloride therapy.
Suprainfection
Photosensitivity
Discoloration of newly forming teeth
GI symptoms (when administed orally)
1st generation cephalosporins are effective against ___ organisms, the 3rd generation are effective against…
Both gram-positive and gram negative
Increased activity against gram-negative but greatly decreased activity against gram-positive microorganisms
Sulfonamides and trimethoprim are synergistic bacteriostatic agents because in bacteria they…
Interfere sequentially with folinic acid production
Tetracycline chelates with ___
Calcium
The concurrent administration of penicillin G and probenecid results in…
Decreased renal excretion of penicillin G
When broad-spectrum antibiotics are administered with coumarin anticoagulants, the anticoagulant action may be [increased/decreased] because of…
Increased
Reduction of vitamin K sources
Erythromycin should be avoided in the patient taking ___ because…
Seldane or digoxin
Erythromycin-seldane potentially lethal interaction whereby erythromycin blocks the metabolism of seldane into its antihistamine metabolite - it stays unmetabolized and causes CARIDAC ARRHYTHMIAS.
What type of drug is furosemide?
Diuretic that is a loop-acting diuretic (high ceiling) used to treat hypertension.
Prazosin is a ___ blocker
Alpha-1
Name two centrally acting adrenergic drugs
Methyldopa
Clonidine
Name one neuronal blocker reserved for severe hypertension
Guanethidine
Name two angiotensin converting enzyme inhibitors used to treat hypertension
Lisinopril
Captopril
Lidocaine can be used to treat ___ arrhythmias
Ventricular
__ is used to reverse digitalis-induced arrhythmias
Phenytoin
___ is used to treat supraventricular tachyarrhthmias and atrial fibrillation
Quinidine
And
Verapamil
__ is used to treat atrial fibrillation and paroxysmal tachycardia and also increases contractility
Digitalis
___ is a beta blocker used to treat paroxysmal tachycardia
Propranolol
Name two glycosides and one ACE inhibitor that is used to treat congestive heart failure
Digitalis
Digoxin
Captopril
Type 1A antiarrhythmics such as ___ act by…
Quinidine
Increasing the refractory period of cardiac muscle
Type 1B antiarrhythmics such as ___ decrease ____
Lidocaine
Cardiac excitability
When digitalis is used for atrial fibrillation it acts by decreasing the rate of ___
AV conduction
Antiangina drugs work by…
Providing increased oxygen supply to the myocardium
How does nitroglycerin treat angina?
Increases oxygen supply to the heart by a direct vasodilators action on the smooth muscle in coronary arteries
How does propranolol treat angina?
Reduces oxygen demand by preventing chronotropic responses to endogenous epinephrine, emotions, and exercise
How do calcium channel blockers treat angina?
Decrease oxygen demand by reducing afterload by reducing peripheral resistance via vasodilation
Captopril is a ___ inhibitor that…
ACE
Inhibits the conversion of angiotensin 1 to angiotensin 2. The latter is a potent vasoconstrictor (administration of angiotensin will result in an elevation of blood pressure)
Prazosin is a selective __ blocker. It inhibits__ resulting in ___
Alpha 1
Binding of nerve induced release of NE resulting in vasodilation
Methyldopa acts centrally as a false neurotransmitter stimulating __ receptors to reduce sympathetic outflow resulting in ___
Alpha
Vasodilation
Clonidine is a selective agonist that stimulates ___ receptors in the CNS to reduce sympathetic outflow to peripheral vessels resulting in vasodilation
Alpha 2
Propranolol is a nonselective ___ blocker that reduces cardiac output and inhibits __ secretion
Beta
Renin
Metoprolol is a [nonselective/selective] beta-1 blocker that reduces cardiac output
Selective
What is the function of diuretics?
Decrease the renal absorption of sodium, thus resulting in fluid loss and a reduction in blood volume. This decreases the work the heart has to pump. Also have a weak dilatory action. Types of diuretics which may be mentioned include…
Thiazides
High-ceiling or loop acting
Potassium sparing
___ such as __ or __ are effective for treating congestive heart failure because they have a positive inotropic effect, increasing the force of contraction of the myocardium. This is achieved by an inhibition of NaKATPase leading to increased calcium influx.
Cardiac glycosides
Digitalis
Digitoxin
Verapamil is most efficacious in the treatment of ___
Atrial fibrillation
What is the drug of choice for the initial therapy of mild hypertension?
Chlorothiazide
True or false.. guanethidine and ganglionic blocking agents are usually reserved for the treatment of severe hypertension
True
Most drugs useful in the treatment of cardiac arrhythmias act primarily by…
Increasing the refractory period of cardiac muscle
Define arrhythmias.
How do they result?
Arrhythmias are defined as any abnormality of the normal sinus rhythm of the heart due to disease or injury induced damage to the impulse conducting systems. They also result form the development of ectopic pacemakers or abnormal pacemaker rhythms.
Propranolol is of value in treating angina pectoris because it…
Prevents chronotropic responses to endogenous epinephrine emotions and exercise
Administration of angiotensin results in [increased/decreased] blood pressure
Increased
The primary antihypertensive effect of captopril is due to accumulation of ___
Angiotensin 1 (because it is not converted to angiotensin 2.
Captopril also maintains lowered BP by elevating bradykinin (which has potent vasodilatory action) in the blood by blocking its metabolism.
The most useful diuretic drugs act by [increasing/decreasing] the renal reabsorption of sodium
Decreasing
___ is a class of antihypertensive drugs that act by inhibiting renal reabsorption of sodium.
Chlorothiazide
How does digoxin exert its positive inotropic effect?
Inhibition of Na+K+ATPase, leading to increased calcium influx
Cardiac glycosides such as digoxin are thought to act by altering calcium ion movement, with a desired effect of increasing the force of contraction of the myocardium (inotropic effect).
Digitoxin is effective in the treatment of cardiac failure because it…
Has a positive cardiac inotropic action
The primary action of therapeutic doses of digitalis on cardiac muscle is an increase in…
Force of contraction
In the treatment of congestive heart failure, digitalis glycosides generally decrease what 4 things?
Edema
Heart size
Heart rate
Residual diastolic volume
The mechanism of action of prazosin, an antihypertensive agent is to…
Inhibit the postsynaptic action of NE on vascular smooth muscle
Selective beta-1 adrenergic agonists will produce [increased/decreased] cardiac output
Increased
Administration of ___ increases the likelihood of a toxic response to digitalis. It is a diuretic which causes potassium loss or hypokalemia. This results in greater penetration of digitalis into the myocardium, and thus potential toxicity
Chlorothiazide
Chlorothiazide is contraindicated with digitalis
The highest risk associated with use of oral contraceptives is…
Thromboembolic disorders
How doe sulfonyl ureas cause insulin secretion?
Direct stimulation of pancreatic beta cells
If a patient requiring an extraction reports that he is on dicoumarol therapy, the laboratory test most valuable in evaluating the surgical risk is ___
Plasma prothrombin time
The various insulin preparations useful in the treatment of diabetes myelitis differ primarily in ___
Onset and duration of action
1) fast-acting (insulin suspension)
2) intermediate acting (isophane insulin suspension)
3) long acting: protamine zinc insulin suspension
Which anticancer drug can be classified as an antimetabolite?
Methotrexate - example of a cell cycle specific antimetabolite that inhibits DNA synthesis during the S phase.
Most cancer chemotherapy drugs cause cell death by affecting the ability of cells to divide.
Which hormone acts to elevate blood concentration of ionic calcium?
Parathyroid
Why shouldn’t a heroin dependent patient be given nalbuphine?
The mixed agonist-antagonists were designed to combine analgesia with enough antagonistic properties to prevent their abuse. It can elicit withdrawal symptoms in a herosin dependent patient.
___ can be used to treat life-threatening ventricular arrhythmias
Lidocaine
A patient on coumadin therapy presents for an extraction yet has a prolonged PT time. What is the correct course of action?
Withdrawing coumadin for 2 days after consulting with physician
What is the drug of choice for status epilepticus?
Diazepam
Bradycardia is most commonly treated with what drug?
Atropine
Bradycardia a reflexive slowed heart rate, controlled by vagal input to the heart, and is cholinergically mediated, which means you need a cholinergic receptor blocker to reduce the vagal effect.
What group of drugs is contraindicated for patients who have glaucoma?
Anticholinergics
Anticholinergics will increase intraocular pressure, which is already the problem with glaucoma patients
Low dose aspirin therapy prevents the formation of thromboembolism by what mechanism?
Inhibiting thromboxane synthetase in the platelets
Succinylcholine blocks neuromuscular transmission by…
Depolarizing the motor endplate of skeletal muscle to overstimulate the receptor, thereby causing its subsequent depolarization of the neuron and a block of muscle activity
How does curare block neuromuscular transmission?
Nicotinic receptor blocker
What is buspirone used for?
To relieve anxiety. It is not a benzodiazepine and does not have as much CNS depression
A patient with which of the following conditions is most likely to have postoperative bleeding after multiple extractions? Why?
Angina Diabetes Cirrhosis Rheumatic fever Chronic bronchitis
Cirrhosis
vitamin K is stored in the liver - this is decreased by cirrhosis - the result is deficiencies in prothrombin dependent coagulation factors
Local anesthetics aid in reducing the flow of saliva during operative procedures by…
Reducing sensitivity and anxiety during tooth preparation
Which is more potent, oxycodone or codeine?
Oxycodone
Auditory nerve deafness is associated with the use of what antibiotic?
Gentamicin
What is the main adverse side effect of the following antibiotics?
Polymixin
Chloramphenicol
Amphotericin B
Gentamycin
Polymixin - renal necrosis
Chloramphenicol - bone marrow depression
Amphotericin B - nephrotoxicity
Gentamycin - auditory nerve deafness
Allergic reactions to local anesthetics are caused by ___
An antigen-antibody reaction
What drug class is amantadine?
Antiviral
What drug class are ephedrine, tyramine, and amphetamine classified under?
Indirect-acting sympathomimetics
Thrombophlebitis, which occurs after IV administration of diazepam is usually attributed to which substance of the mixture?
Propylene glycol
Name 3 signs that a patient is being administered too much nitrous oxide.
Nausea
Euphoria
Giddiness
(Tingling of the hands is usually the first symptom that is perceived by patients)
