Neuromuscular Blockade - Chapter 13 Flashcards
Neuromuscular Blocking Drugs
-Interfere with transmission at the neuromuscular endplate and are primarily used as adjuncts during general anesthesia to paralyze a patient so there is no movement during surgery
Mechanism For Skeletal Muscle Contraction
- Occurs as a response to communication between peripheral nerves and muscles
- Calcium stimulates the release of ACh which binds to nicotinic receptor sites located in the muscle soleplate. ACh binding causes an influx of calcium and potassium ions which results in muscle contraction
Neuromuscular Blockade MOA
- Increasing inactive ACh nicotinic receptor sites
- Decreasing ACh release
- Depleting neuronal ACh
Neuromuscular Blocking Agents (NMBA’s)
-Increase the percent of ACh receptor sites that are inactivated, causing relaxation of skeletal muscles
Peripheral Acting Skeletal Muscle Relaxants/Neuromuscular Blockade Agents: Classifications
- Depolarizing blocking agents
- Nondepolarizing blocking agents
Depolarizing Blocking Agents
- Bind to ACh receptors and produce sustained depolarization, causing receptors to their inactive state
- Rapidly inactivated by cholinesterase enzymes
Depolarizing Blocking Agents Examples
-succinylcholine chloride
Brand: Quelicin
Generic: succinylcholine chloride
Nondepolarizing Blocking Agents
-Common ending: “curonium” and “curium”
- Interfere with Na+, Ca++, and K+ channels and decrease acetylcholinesterase action
- Botulin toxin blocks release of ACh from vesicles
Nondepolarizing Blocking Agents Examples
- atracurium
- cistracurium
- pancuronium
- rocuronium
- vecuronium
- botulin toxin type A
- incobotulinum toxin A
- abotulinum toxin A
Brand: atracurium
Generic: atracurium
Brand: Nimbex
Generic: cistracurium
Brand: pancuronium
Generic: pancuronium
Brand: Zemuron
Generic: rocuronium
Brand: vecuronium
Generic: vecuronium
Brand: Botox
Generic: botulin toxin type A
Brand: Xeomin
Generic: incobotulinum toxin A
Brand: Dysport
Generic: abotulinum type A
Botulinum Toxin Type A Use
- Temporarily removes wrinkles
- Excessive sweating
- Uncontrollable blinking
- Spasticity associated with cerebral palsy
- Chronic migraine
- Overactive bladder
Botulinum Toxin Type A ADR’s
- Droopy eyelid muscles
- Headache
- Nausea
- Flulike symptoms
- Redness
- Muscle weakness
NMBA ADR’s
- Allergic reactions
- Muscle pain
- Respiratory depression
- Cardiac arrest
- Itching or burning at injection site
- Hypotension
- Flushing
- Tachycardia or bradycardia
Strategies for safe use of NMBA’s
- NMBA’s are given USP classification of high alert because improper use can cause permanent injury, respiratory arrest, or death
- Problems may result from improper selection, storage conditions or labelling, inappropriate dosing, or inadequate patient monitoring
Recommendations for Pharmacy Practice with NMBA’s
There are recommendations for:
- Product selection
- Product storage
- Limiting access
- Auxiliary labels and warning labels
- Ordering practices and dispensing
Reversal of Neuromuscular Blockade
-Anticholinesterase drugs inhibit the action of ACh esterase at the neuromuscular junction
Anticholinesterase Drugs Examples
- edrophonium
- neostigmine
- pyridostigmine
Brand: Tensilon
Generic: edrophonium
Brand: Prostigmin
Generic: neostigmine
Brand: Mestinon, Mestinon SR
Generic: pyridostigmine
Anticholinesterase Drugs ADR’s
- Salivation
- Muscle twitching
- Muscle weakness
- Abdominal cramping
- Nausea
- Increased bronchial secretions
- Difficulty breathing
