Dantrolene Sodium

Malignant hyperthermia, Chronic severe spasticity of voluntary muscle.

postsynaptic muscle relaxant

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.

Malignant hyperthermia BY RAPID INTRAVENOUS INJECTION Adult: Initially 2-3 mg/kg, then 1 mg/kg, repeated if necessary; maximum 10 mg/kg per course Chronic severe spasticity of voluntary muscle BY MOUTH Adult: Initially 25 mg daily, then increased to up to 100 mg 4 times a day, dose increased at weekly intervals; usual dose 75 mg 3 times a day

Drowsiness may occur with Dantrolene therapy, and the concomitant administration of CNS depressants such as sedatives and tranquilizing agents may result in further drowsiness. Hepatotoxicity has occurred more often in women over 35 years of age receiving concomitant estrogen therapy.

CONTRA-INDICATIONS With oral use Acute muscle spasm . avoid when spasticity is useful, for example, locomotion CAUTIONS With intravenous use Avoid extravasation (risk of tissue necrosis) With oral use Females (hepatotoxicity) . history of liver disorders (hepatotoxicity) . if doses greater than 400mg daily (hepatotoxicity) . impaired cardiac function . impaired pulmonary function . patients over 30 years (hepatotoxicity) . therapeutic effect may take a few weeks to develop?discontinue if no response within 6?8 weeks

Common or very common With oral use Abdominal pain . anorexia . asthenia . chills . diarrhoea (withdraw if severe, discontinue treatment if recurs on re-introduction) . dizziness . drowsiness . fatigue . fever . headache . hepatotoxicity . nausea . pericarditis . pleural effusion . rash . respiratory depression . seizures . speech disturbances . visual disturbances . vomiting Uncommon With oral use Confusion . constipation . crystalluria . depression . dysphagia . dyspnoea . erratic blood pressure . exacerbation of cardiac insufficiency . haematuria . increased sweating . increased urinary frequency . insomnia . nervousness . tachycardia . urinary incontinence . urinary retention Frequency not known With intravenous use Dizziness . erythema . hepatotoxicity . injection-site reactions . pulmonary oedema . rash . swelling . thrombophlebitis . weakness

PREGNANCY With intravenous use Use only if potential benefit outweighs risk. With oral use Avoid use in chronic spasticity?embryotoxic in animal studies. BREAST FEEDING With intravenous use Present in milk?use only if potential benefit outweighs risk. With oral use Present in milk?manufacturer advises avoid use in chronic spasticity.

Store in a cool & dry place, protected from light.