Neuromusclar Blocking Agents (NMBAs) Flashcards
1
Q
Depolarizing Blockers
A
- Cause excessive depolarization of the NMJ
2
Q
Non depolarizing agents
A
- Competitive
2. Inhibit depolarization of the NMJ
3
Q
Acetylcholine
A
- NTM at the NMJ
- Rapidly metabolized by acetylcholinesterase to terminate its effects
- Interference of its effects at the nicotinic receptors of the NMJ cause muscle relaxation
4
Q
Depolarizing NMB: Succinylcholine Chloride
A
- White, colorless, slightly bitter powder and very soluble in water
- Unstable in alkaline solutions but STABLE in ACID solutions
- Should be stored in refrigeration to preserve potency
- PH adjusted to 3.5 w/ HCL (methylparaben added for preservative)
* Chloride is added to counteract succ positive charge
* do not mix w/ alkaline solutions greater than 8.5 (ex barb solutions)
5
Q
Depolarizing NMB: Decamethonium Bromide
A
- Quart. Amine (bromide added to counter act positive charge)
- Although it has similar structure to succ,No longer used clinically
6
Q
Non depolarizing NMB are also ________
A
Competitive*****
7
Q
Benzylisoquionlium Compounds
A
Nondepolarizing or competitive NMB agents
8
Q
d- Tubocurarine Chloride
A
- Nondepolarizing-competitive.
- Extracted from plant family chondodenron
- Commercial solutions contain a preservative and are adjusted to ph 2.5-5
9
Q
Pancuronium Bromide
A
- Non depolarizing Competitive NMB
- Quarternary steroidal compounds
- Bromide counter acts positive charge
10
Q
Vecuronium Bromide
A
- Non depolarizing competitive NMB agent
- Quartnernary steroidal compounds
- Each 10 ml vial contains 10 mg of vec. Bromide
- Sodium hydroxide added to buffer and adjust pH to 4
- Powder should be stored away from light and refrigerated
- Ester makes it more susceptible to hydrolysis because it is not protected by quaternary amine
11
Q
Atracurium Besylate
A
- Non depolarizing competitive NMB- Benzylisoquinolinium compound
- Four sites at which different configurations can occur
- 2 chances of hydrolysis- very quick acting
- Adjusted to pH of 3.25-3.65 w/ benzensuflonic acid
- Incompatible w/ alkaline solutions
12
Q
Atracurium biotransformation-hydrolysis
A
- Non specific enzymatic ester hydrolysis
- Rate is INdependent of plasma cholinesterase concentration
- Hydrolysis rate is enhanced by physiological decrease in acidity
13
Q
Metabolites of atracurium biotransformation-hydrolysis
A
- Devoid of NMB activity and CV effects
* atracurium can also undergo cleavage between the carbonyl group and the nitrogen group via a process called the Hoffman elimination. Metabolism by hoffman and ester hydrolysis is nearly complete
14
Q
Mivacurium chloride
A
- Non depolarizing (competitive) NMB- benzylisoquinolinium compound
- Mixture of 3 stereoisomers-
- cis-trans diester
- trans-trans diester
- cis- cis diester
15
Q
Cholingers
A
- Inhibits acetylcholinesterase, therefore increases ACH at the cholingeric receptor and reverses the effects of non depolarizing blockers