Dantrolene Sodium

Dantrolene Sodium has a direct action on skeletal muscle. It uncouples muscular contraction from excitation, probably by interfering with calcium release from sarcoplasmic reticulum. It produces relaxation by affecting the contractile response of the skeletal muscle at a site beyond the myoneural junction, directly on the muscle itself. It is indicated in controlling the manifestations of clinical spasticity resulting from upper motor neuronal disorders (e.g., spinal cord injury, stroke, cerebral palsy, or multiple sclerosis).

• Chronic spasticity (spinal cord injury, stroke, cerebral palsy, multiple sclerosis)
• Prevention and treatment of malignant hyperthermia

Dantrolene produces relaxation by affecting the contractile response of the skeletal muscle at a site beyond the myoneural junction, directly on the muscle itself. In skeletal muscle, Dantrolene dissociates the excitation-contraction coupling, probably by interfering with the release of Ca++ from the sarcoplasmic reticulum.

Dantrolene interferes with calcium release from the sarcoplasmic reticulum, dissociating excitation-contraction coupling, thereby inhibiting muscle contraction and producing muscle relaxation.

Adult - Chronic Spasticity: Initially, 25 mg twice daily, gradually increased by 25-50 mg/day per week. Maximum: 400 mg/day. Discontinue if no response after 45 days.

Child - Chronic Spasticity: Initially, 0.5 mg/kg once daily for 7 days, then gradually increased to 2 mg/kg 3-4 times daily. Maximum: 100 mg 4 times daily.

Malignant Hyperthermia (Preoperative): 4-8 mg/kg/day in 3-4 divided doses for 1-2 days prior to surgery, with last dose given 3-4 hours before scheduled surgery.

May be taken with or without food. Swallow the capsule whole, do not chew, crush or break it. Dosage should be increased gradually.

If you miss a dose of Dantrolene, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose. Do not double the dose.

Common: Drowsiness, dizziness, muscle weakness/pain, fatigue, diarrhea, GI disturbances, CNS effects, tachycardia, unstable BP, dyspnoea, rashes, pruritus, fever, visual disturbances, dysphagia, speech disturbances, haematuria.
Serious: Hepatotoxicity, aplastic anemia, leukopenia, thrombocytopenia, pleural effusion with pericarditis.

• Perform LFTs before and during treatment.
• Increased risk of liver injury in patients >30 years, especially those on estrogen therapy, history of liver disease, or daily dose >400 mg.
• Avoid driving or hazardous occupations (drowsiness, dizziness may occur).
• If diarrhea is severe, temporarily withdraw Dantrolene. If diarrhea recurs on readministration, withdraw permanently.
• Discontinue if no benefit is evident within 45 days.

• Active liver disease (hepatitis and cirrhosis)
• Acute muscle spasm
• Patients who use their spasticity to maintain posture or function
• Lactation

CNS depressants (sedatives, tranquilizers): May result in further drowsiness.

Oestrogens: Hepatotoxicity has occurred more often in women over 35 years receiving concomitant estrogen therapy.

Calcium-channel blockers: May interact.

Alcohol or CNS depressants: CNS effects are enhanced.

May be taken with or without food. Caution is advised with alcohol consumption.

Pregnancy Category C. Dantrolene should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Dantrolene enters breast milk and is not recommended for use in nursing mothers.

Long-term safety in pediatric patients under 5 years of age has not been established.

Elderly patients have increased risk of liver injury (especially women over 35 years). Use with caution.

Use with caution in patients with liver or kidney disease. Regular monitoring of liver function tests is advised.

Overdose may lead to muscle weakness, drowsiness, diarrhea, and liver toxicity. Seek medical attention.

Store in a cool & dry place, protected from light. Keep out of reach of children.

Dantrolene Sodium