Neuromusclar Blocking Agents (NMBAs) Flashcards Preview

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Flashcards in Neuromusclar Blocking Agents (NMBAs) Deck (20)
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Depolarizing Blockers

1. Cause excessive depolarization of the NMJ


Non depolarizing agents

1. Competitive
2. Inhibit depolarization of the NMJ



1. NTM at the NMJ
2. Rapidly metabolized by acetylcholinesterase to terminate its effects
3. Interference of its effects at the nicotinic receptors of the NMJ cause muscle relaxation


Depolarizing NMB: Succinylcholine Chloride

1. White, colorless, slightly bitter powder and very soluble in water
2. Unstable in alkaline solutions but STABLE in ACID solutions
3. Should be stored in refrigeration to preserve potency
4. 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)


Depolarizing NMB: Decamethonium Bromide

1. Quart. Amine (bromide added to counter act positive charge)
2. Although it has similar structure to succ,No longer used clinically


Non depolarizing NMB are also ________



Benzylisoquionlium Compounds

Nondepolarizing or competitive NMB agents


d- Tubocurarine Chloride

1. Nondepolarizing-competitive.
2. Extracted from plant family chondodenron
3. Commercial solutions contain a preservative and are adjusted to ph 2.5-5


Pancuronium Bromide

1. Non depolarizing Competitive NMB
2. Quarternary steroidal compounds
3. Bromide counter acts positive charge


Vecuronium Bromide

1. Non depolarizing competitive NMB agent
2. Quartnernary steroidal compounds
3. Each 10 ml vial contains 10 mg of vec. Bromide
4. Sodium hydroxide added to buffer and adjust pH to 4
5. Powder should be stored away from light and refrigerated
6. Ester makes it more susceptible to hydrolysis because it is not protected by quaternary amine


Atracurium Besylate

1. Non depolarizing competitive NMB- Benzylisoquinolinium compound
2. Four sites at which different configurations can occur
3. 2 chances of hydrolysis- very quick acting
4. Adjusted to pH of 3.25-3.65 w/ benzensuflonic acid
5. Incompatible w/ alkaline solutions


Atracurium biotransformation-hydrolysis

1. Non specific enzymatic ester hydrolysis
2. Rate is INdependent of plasma cholinesterase concentration
3. Hydrolysis rate is enhanced by physiological decrease in acidity


Metabolites of atracurium biotransformation-hydrolysis

1. 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


Mivacurium chloride

1. Non depolarizing (competitive) NMB- benzylisoquinolinium compound
2. Mixture of 3 stereoisomers-
- cis-trans diester
- trans-trans diester
- cis- cis diester



1. Inhibits acetylcholinesterase, therefore increases ACH at the cholingeric receptor and reverses the effects of non depolarizing blockers



1. Inhibits ACHE, increases Ach at cholingeric receptor and reverses the effects of non depolarizing (competitive) blockers
2. Has carbamate ring- ester in which there is a nitrogen bound to a carbon



1. Charged- small molecule
Needs counter ion in solution


Pyridostigmine Bromide

Need bromide as counter ion


Edrophonium chloride

1. Cholingeric
2. Has sodium sulfite as preservative and is buffered with citric acid and adjusted to ph 4
3. Do NOT undergo hydrolysis, no site for this



1. New NMB reversal agent is undergoing clinical trials targeted to reversing rocuronum
2. Binding w/ roc and similar steroid NMB agents
3. Excreted by kidney
4. Has cycodextrins that are circular sugar-containing compounds that form a cone with a hollow core. Steroid compounds are induced in the hollow cone of the cyclodextrin molecule and this causes reversal of the NMB effect