Skeletal muscle relaxant

Mechanism

Clinical use

Notes

GABAB receptor agonist in spinal cord

Muscle spasticity, dystonia, multiple sclerosis

- Acts on the back (spinal cord)
- May cause sedation

Acts within CNS, mainly at the brainstem

Muscle spasms

- Centrally acting
- Structurally related to TCAs
- May cause anticholinergic adverse effects, sedation

Prevents release of Ca²⁺ from sarcoplasmic reticulum of skeletal muscle by inhibiting the ryanodine receptor. It is used in states
that include extreme muscle rigidity, such as malignant hyperthermia associated
with inhaled anesthetics and skeletal muscle relaxants or neuroleptic malignant
syndrome associated with anti psychotics. 

Malignant hyperthermia (toxicity of inhaled anesthetics and succinylcholine) and neuroleptic malignant syndrome (toxicity of antipsychotics)

- Acts directly on muscle

α₂ agonist, acts centrally

Muscle spasticity, multiple sclerosis, ALS, cerebral palsy

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Used after spine surgery

- Diazepam
- Cyclobenzaprine
- Methocarbamol
- Carisoprodol

Category

Dose

Comments

- Non-depolarizing
- For ICU care
- Long-acting (1 bolus = 90 min)

- 0.1 mg/kg iv bolus
- Adjust continuous dose prn

NMBA of choice for ICU care
!! Caution:
- Vagolytic → causing tachycardia
- In renal and liver failure (prolonged half life)

- Non-depolarizing
- Intermediate-acting

1. 0.1 mg/kg bolus
2. Then 1 mcg/kg/min continuous

No histamine release
!! Caution:
- Liver and renal failure → recovery time may be 1-2 d

- Non-depolarizing
- Intermediate-acting

1. 0.5 mg/kg iv bolus
2. Then 10 mcg/kg/min continuous

NMBA of choice for rapid sequence intubation

- Non-depolarizing
- Intermediate-acting

- 0.1 mg/kg bolus,
- 3 mcg/kg/min continuous

- NMBA of choice for renal and liver failure
- Temperature and ph-de-pendent spontaneous Hoffman degradation

- Depolarizing
- Very short acting

- 1.0 mg/kg bolus

- For anesthesia induction and emergencies