NEUROMUSCULAR DRUGS AND MUSCLE RELAXANTS Flashcards
induce temporary paralysis of skeletal muscles
muscle relaxant
CENTRAL ACTING MUSCLE RELAXANTS
- Guaifenesin
- Methocarbamol
- Meprobamate
- Mephenesin
formerly known as glyceryl guaiacolate which is used as an adjunct to anesthesia to produce muscle relaxation and restraint for short procedures
guaifenesin
used as an adjunct to rest and physical therapy in the treatment of musculoskeletal injury, muscular spasm associated with tetanus and metaldehyde or strychnine poisoning
methocarbamol
SITES OF ACTION OF DRUGS CAUSING MUSCLE RELAXATION
- CNS
- Motor nerve fiber
- Motor nerve terminal
- Acetylcholine receptors in motor end plate
- Skeletal muscle fiber
cause muscle relaxation when applied around muscle fibers but not used for the muscle relaxant effect
lidocaine (local anesthetics)
relax skeletal muscles but they are not used routinely for the sole purpose of muscle relaxation
General anesthetics (CNS drugs)
no clinically useful muscle relaxants in this group
motor nerve terminal
prevent the release of Ach from nerve endings, causing muscle relaxation
- botulinus toxin
- aminoglycoside antibiotics
acuronium dosage
Dog and Horse : 0.1 mg/kg under light anesthesia
Dantrolene dosage for dogs
2.5 mg/kg IV q.i.d
Dantrolene dosage for horse
Prophylactic - 1-2 mg/kg oral q.i.d
Malignant hyperthermia - 1-3 mg/kg IV repeated in 10 minutes
Dantrolene dosage for pigs
2-3 mg/kg IV
D-tubocurarine dosage for dogs
approx. 0.4 mg/k
D-tubocurarine dosage for pig
0.3 mg/kg
D-tubocurarine dosage for horse
0.22 - 0.25 mg/kg
Gallamine dosage for dogs and cats
1 mg/kg IV
Gallamine dosage for pig
4 mg/kg
Gallamine dosage for horse
0.5 - 1 mg/kg
Pancuronium dosage for dogs under light anesthesia with methoxyflurane
0.03 mg/kg IV
Succinylcholine dosage for horses
0.12 – 0.15 mg/kg (last for 4-5 min)
Succinylcholine dosage for cattle
0.02 mg/kg (lasts for 6-8 min)
vecuronium dosages for dogs
0.1 mg/kg IV initially 30 min before proof
may give 0.04 mg/kg IV subsequently
Muscle acting on this site are most clinically useful muscle relaxants.
Acetylcholine receptors in motor end plate
decreases sarcoplasmic free calcium concentration by promoting its uptake into the sarcoplasmic reticulum
dantolene
compete with Ach for
cholinergic receptors in the end plate
Nondepolarizing neuromuscular blocking drugs
Nondepolarizing neuromuscular blocking drugs
D-Tubocurarine, gallamine, pancuronium, acuronium,
atracurium, vecuronium
noncompetitive blockes of
cholinergic receptors in the end plate. There is sustained stimulation
leading to receptor fatigue and muscle paralysis
Depolarizing neuromuscular blocking drugs
Depolarizing neuromuscular blocking drugs
Succinylcholine (suxamenthonium), Decamethonium
