The motor neuron diseases (MNDs) are progressive neurological disorders that affect the motor neurons, the cells that control voluntary muscle activity such as speaking, walking, breathing, swallowing and general movement of the body. If the upper motor neurons are affected, the manifestations include spasticity or stiffness of limb muscles and overactivity of tendon reflexes such as knee and ankle jerks.1
Malignant hyperthermia (MH) is a rare life-threatening condition triggered by exposure to certain drugs used for general anesthesia (specifically all volatile anesthetics), nearly all gas anesthetics, and succinylcholine (a neuromuscular blocking/depolarizing muscle relaxant) in patients who have inherited a gene defect for malignant hyperthermia. It may be the cause of sudden, unexpected death in an individual undergoing surgery and is considered one of the most devastating crises encountered in anesthesia.
Dantrium® is a direct acting skeletal muscle relaxant and the capsules are indicated for use in Chronic Spasticity and in MH.
In chronic spasticity, Dantrium® capsules can be used in controlling the manifestations of clinical spasticity resulting from upper motor neuron disorders (e.g., spinal cord injury, stroke, cerebral palsy, or multiple sclerosis). It is of particular benefit to the patient whose functional rehabilitation has been retarded by the sequelae of spasticity. It is not indicated in the treatment of skeletal muscle spasm resulting from rheumatic disorders.
In MH, Dantrium® capsules are indicated preoperatively to prevent or attenuate the development of signs of MH in known, or strongly suspect, MH susceptible patients who require anesthesia and/or surgery and should be administered following a malignant hyperthermic crisis to prevent recurrence of the signs of MH.
Dantrium® is available in capsules of 25 mg, 50 mg, and 100 mg.
1 http://www.ninds.nih.gov/disorders/motor_neuron_diseases/
detail_motor_neuron_diseases.htm (accessed 6/3/09)
Dantrium® (dantrolene sodium) has a potential for hepatotoxicity, and should not be used in conditions other than those recommended. Symptomatic hepatitis (fatal and non-fatal) has been reported at various dose levels of the drug. The incidence reported in patients taking up to 400 mg/day is much lower than in those taking doses of 800 mg or more per day. Even sporadic short courses of these higher dose levels within a treatment regimen markedly increased the risk of serious hepatic injury. Liver dysfunction as evidenced by blood chemical abnormalities alone (liver enzyme elevations) has been observed in patients exposed to Dantrium® for varying periods of time. Overt hepatitis has occurred at varying intervals after initiation of therapy, but has been most frequently observed between the third and twelfth month of therapy. The risk of hepatic injury appears to be greater in females, in patients over 35 years of age, and in patients taking other medication(s) in addition to Dantrium® (dantrolene sodium). Dantrium® should be used only in conjunction with appropriate monitoring of hepatic function including frequent determination of SGOT or SGPT. If no observable benefit is derived from the administration of Dantrium® after a total of 45 days, therapy should be discontinued. The lowest possible effective dose for the individual patient should be prescribed.