Muscle Relaxants 111

Skeletal muscle relaxants act peripherally at
the neuromuscular junction or centrally in
the cerebrospinal axis to reduce muscle tone.

Skeletal muscle relaxation can be achieved
by following group of drugs as in table 2.7.1.

NEUROMUSCULAR BLOCKERS

D-TUBOCURARINE

It is an dextrorotatory quarternary
ammonium alkaloid obtained from

Chondrodendron tomentosum plant. It ini-

tially produced motor weakness fol-

lowed by flaccid paralysis after

parenteral administration. The paralysis

occurs in following order e.g. paralysis

of fingers, toes, eyes, ears producing

diplopia, speech slurring, difficulty in

swallowing; the muscles of neck, limb,

trunk, paralysis of diaphragm and death

occur due to hypoxia.

In higher doses, d-tubocurarine can

produce blockade of autonomic ganglia. It

Table 2.7.1: Classification of skeletal muscle relaxants.

I. Neuromuscular blockers

d-Tubocurarine 0.2-0.4 mg IV

Atracurium 10-15 mg IV

Pancuronium 40-100 μg/kg IV

Vecuronium 0.08-0.1 mg/Kg IV

Succinylcholine 30-50 mg IV

Benzoquinonium 10-15 mg IV

Dantrolene 25 to 100 mg/day

II. Centrally acting muscle relaxants

Mephenesin

Chlorzoxazone (MOBIZOX) 250 mg TDS

Methocarbamol (FLEXINOL) 0.l5-1 g/day oral, 100-200 mg IM/IV

Carisoprodol (CARISOMA) 350 mg TDS

Orphenadrine (ORPHIPAL) 100-300 mg/day

Tizanidine (CITANZ) 2-6 mg/day

Baclofen (LIORESAL) 30-75 mg/day

Metaxalone (FLEXURA) 400-800 mg TDS-QID

(Mode of Action of Drugs)

PharmacodynamicsPharmacodynamicsPharmacodynamicsPharmacodynamicsPharmacodynamicsPharmacodynamicsPharmacodynamicsPharmacodynamicsPharmacodynamicsPharmacodynamics

Chapter

1.4

Chapter

2.7 Muscle Relaxants

Muscle

Relaxants