Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Anesthesia
Local Anesthesia CH. 3 Pharmacology of Vasocontrictors PG. 41-53
| Question | Answer |
|---|---|
| What happens after a local anesthetic is injected into the tissues? | Blood vessels in the area dilate, resulting in increased perfusion at the site. |
| When blood vessels dilate, resulting in increased perfusion at the site of injection what reactions occur? | Increased rate of absorption into cardiovascular system removing it from the injection site. Higher plasma levels. Increase risk of toxicity. Decrease in depth and duration due to anesthetic diffusing away from injection site. Increased bleeding at site. |
| Why are vasoconstrictors important additions to local anesthetic solution? | decrease blood flow at the site of administration, absorption of the anesthetic in the cardiovascular system is slowed resulting in lower blood levels. Increases the duration of action. |
| What are local anesthetics chemically identical or similar to? | Sympathetic nervous system mediators epinephrine and norepinephrine |
| What are naturally occurring catecholamines of the sympathetic nervous system? | Epinephrine, norepinephrine, and dopamine |
| Direct-acting drug | exert their action directly on adrenergic receptors |
| Indirect-acting drugs | releasing norepinephrine from adrenergic nerve terminals |
| Mixed-acting drugs | both direct and indirect acting drugs |
| What happens when the alpha receptors are activated? | produces a response that includes contraction of smooth muscle in blood vessels (vasoconstriction) |
| What are alpha 1 receptors? | excitatory-postsynaptic |
| What are alpha 2 receptors? | inhibitory-postsynaptic |
| What happens when the beta receptors are activated? | smooth muscle relaxation (vasodilation and bronchodilation) and cardiac stimulation (increased heart rate and strength of contraction) |
| What can amphetamines do? | act indirectly by causing the release of the catecholamine norepinephrine from storage sites in adrenergic nerve terminals and may exert direct action on alpha and beta receptors |
| Tachyphylaxis | Successively repeated doses of drugs will prove to be less effective than those given previously because the depletion of norepinephrine from storage sites. |
| What is the epinephrine reaction? | Sufficient epinephrine can be absorbed to cause sympathomimetic reactions such as apprehension, tachycardia, sweating, pounding in the chest (palpitation). |
| What vasoconstrictor should never be used in dentistry? | combination of epinephrine and norepinephrine |
| What is the most common effective vasoconstrictor used in dentistry today? | Epinephrine |
| What is another name for epinephrine? | Adrenalin |
| Why is sodium bisulfite added to epinephrine solutions? | Delay its deterioration |
| Epinephrine is used as a vasoconstrictor predominately for what? | Hemostasis |
| What is used as management of acute asthmatic episodes (bronchiole)? | Epinephrine |
| Epinephrine's action is terminated by what? | Reuptake by adrenergic nerves |
| Clinical manifestations of epinephrine overdose include what? | fear and anxiety, tension, restlessness, throbbing, headache, tremor, weakness, dizziness, pallor, respiratory difficulty, and palpitation. |
| When should you limit or avoid the use of epinephrine/ vasoconstrictor? | Cardiovascular compromised patients, ASA III and ASA IV |
| This vasoconstrictor should not be used at all in local anesthetic, according to some authorities what is it? | Norepinephrine |
| T/F Norepinephrine is used as management for hypotension. | True |
| What are the systemic actions of levonordefrin? | less cardiac and CNS stimulation than epinephrine |
| What is stated according to Epinephrine and Levonordefrin? | Levonordefrin has the same effects as epinephrine but to a lesser degree. |
| What factors should be considered if and when using a vasoconstrictor? | Length of the dental appointment, need for hemostasis during and after, postoperative pain control, medical status of the patient. |
| What happens when tissue level of epinephrine declines? | rebound vasodilatory effect |
| Vasopressors in local anesthetics solution must be weighed against the benefits and risks of using a plain local anesthetic. What are the groups in this category? | Patients with significant cardiovascular disease ASA III and IV, certain noncardiovascular disease ( thyroid dysfunction, diabetes, sulfite sensitivity), MAO inhibitors, tricyclic antidepressants, and phenothiazines |
| Epinephrine is contraindicated in patients that have clinical evidence of what? | Hyperthyroid state |
| What is absolutely contraindicated in patients receiving tricyclic antidepressants? | administration of levonordefrin or norepinephrine |
Created by:
daisenmurray
Popular Dentistry sets