OBJECTIVES:
I. Assess the efficacy of dichlorphenamide in the treatment of episodic weakness attacks in patients with hyperkalemic periodic paralysis, paramyotonia congenita with periodic paralysis, and hypokalemic periodic paralysis.
PROTOCOL OUTLINE: This is a randomized, double-blind study. Patients are stratified by participating institution and diagnosis.
The weekly attack rate is determined during an 8-week assessment prior to therapy initiation and at crossover.
Patients are randomly assigned to oral dichlorphenamide (DCP) or placebo for 9 weeks and then cross to the alternate treatment. Patients on DCP at baseline continue on the same dose; those on acetazolamide (ACZ) at baseline receive a DCP dose equivalent to one fifth of the ACZ dose.
PROTOCOL ENTRY CRITERIA:
--Disease Characteristics--
Hypokalemic periodic paralysis Typical clinical profile Normal serum thyroxine Hypokalemia during spontaneous or glucose-induced paralytic attack in subject or affected family member
Periodic paralysis associated with sodium channel 17q alpha-subunit, e.g.:
Distinct, regular episodes of weakness at least once a week and no more than 3 times a day
No history of worsening symptoms with carbonic anhydrase inhibitor
No history of life-threatening weakness episodes prior to treatment
No atypical periodic paralysis without demonstrable 17q alpha-subunit defect
--Prior/Concurrent Therapy--
No requirement for the following agents, unless for periodic paralysis:
--Patient Characteristics--
Hepatic: No hepatic disease
Renal:
Cardiovascular:
Pulmonary: No restrictive or obstructive lung disease
Other: