Vasoconstrictors-Pain-1 Flashcards
(56 cards)
All clinically effective injectable local anesthetics are
vasodilators
Local anesthetic injection into tissues results in, ______(decreased/increased ) perfusion at thesite
increased
Local anesthetic injection into tissues results in, increased perfusion at thesite, leading to the following reactions
- Increased rate of absorption into thecardiovascular system, removes it from theinjection site (redistribution)
- Higherplasmalevelsof the local anesthetic, increases in therisk of localanesthetic toxicity (overdose)
- Decrease in both the depth and duration of anesthesia because the local anesthetic diffuses away fromthe injection site more rapidly
- Increased bleeding atthe siteof treatment asa result of increased perfusion
Vasoconstrictors are important additions to a local anesthetic solution for thefollowing reasons:
- By constricting blood vessels, vasoconstrictors decreaseblood flow (perfusion) tothe site of drug administration.
- Absorption of the local anesthetic intothe cardiovascular system is slowed, resulting in lower anesthetic blood levels.
- Localanesthetic blood levelsare lowered,thereby decreasingthe risk oflocalanesthetic toxicity.
- More local anesthetic enters into the nerve, where it remainsfor longer periods,thereby increasing the duration of action (in some cases significantly, in others minimally) of most local anesthetics.
- Vasoconstrictorsdecrease bleeding at the siteof administration;therefore they are useful when increased bleeding is anticipated (e.g., during asurgical procedure)
Catecholamine
- Epinephrine
- Norepinephrine
- Levonordefrin
- Isoproterenol
- Dopamine
Non-catecholamine
- Amphetamine
- Methamphetamine
- Ephedrine
- Phenylephrine
Direct Acting Drugs
exert their action directly on adrenergic receptors
Indirect Acting Drugs
stimulate the release of the cathecholamine norepinephrine from adrenergic nerve terminals (Tachyphylaxis)
Mixed Acting
acts on both direct and indirect receptors
Activation of A receptors by a sympathomimetic drug usually produces a response that includes
contraction of smooth muscle in blood vessels (vasoconstriction).
A 1 receptors =
excitatory-postsynaptic
A 2 receptors =
inhibitory-postsynaptic
Activation of beta receptors produces ?
smooth muscle relaxation (vasodilation andbronchodilation) and cardiac stimulation (increased heart rate and strength ofcontraction).
Beta 1are found in
heart and small intestines
Beta 1are responsible for ? (slide 15)
cardiac stimulation and lipolysis;
Beta 2are found in
the bronchi, vascular beds, and uterus,
Beta 2are responsible for ? (slide 17)
produce bronchodilation and vasodilation
A concentration of1:1000means?
1 g(1000mg)of solute(drug) iscontained in 1000mL of solution.
Epinephrine concentrations used in clinical dentistry are much lower yet very effective.
T/F
T
To producea 1:10,000 concentration,1 mLof a1:1000solution is added to___mLof solvent(e.g., sterile water);
To producea 1:10,000 concentration,1 mLof a1:1000solution is added to9 mLof solvent(e.g., sterile water); therefore 1:10,000 = 0.1 mg/mL (100µg/mL)
To producea 1:100,000concentration, 1mL ofa 1:10,000concentration isaddedto___mL ofsolvent
To producea 1:100,000concentration, 1mL ofa 1:10,000concentration isaddedto 9mL ofsolvent;
therefore 1:100,000 = 0.01 mg/mL (10 µg/mL)
How much in a cartridge?
If a 1:100,000 concentration contains 0.01mg/ml and a cartridge contains 1.7 ml of solution, then:
0.01 mg/ml X 1.7 ml = .017 mg per cartridge
If you use 2 cartridges, then 2 X .017 = .034 mg
How much in a cartridge?:
If a 1:100,000 concentration contains 0.01mg/ml and a cartridge contains 1.7 ml of solution, then:
0.01 mg/ml X 1.7 ml = .017 mg per cartridge
If you use 2 cartridges, then 2 X .017 = .034 mg
epinephrine reaction
even following usual precautions (e.g., aspiration, slow injection), sufficient epinephrine can be absorbed to cause sympathomimetic reactions such as apprehension, tachycardia, sweating, and pounding in thechest (palpitation)—the so-called epinephrine reaction.
