Rigidity refers to a group of symptoms that are caused by bradykinesia, or the slowing of voluntary movements. Voluntary movements control walking, talking, swallowing, and many other activities of daily life. In Huntington's each of these activities slow as the disease progresses. There are very few treatments and no clinical studies specifically testing drugs for this symptom.

Rigidity Treatments: Though this is a symptom that causes great disability, reports are limited to single patient response to drugs. These reports detail improvement in rigidity by the use of pramapexole (Miripex) [Bonelli 2002], L-dopa [Racette 1998], and amantadine [Magnet 2004]. Note that, at least in theory, L-dopa may be harmful to neurons in HD so is probably not the drug to try first. Note also that amantadine is also sometimes used to treat chorea. It is likely that L-dopa and amantadine may have different actions at different stages of Huntington's disease.

Commonly Used Rigidity Medications

Pramipexole (Mirapex®): This is a dopamine drug that is most often used in Parkinson's disease and restless leg syndrome. Dosage starts at 0.125 mg three times a day, and is increased slowly by 0.125 mg every 3-7 days. Side effects include sleepiness and dry mouth as well as hallucinations (in Parkinson's).

Carbedopa-levodopa (Sinemet®): This is a dopamine drug that is used in Parkinson's disease. Side effects include nausea, dizziness and headache, and hallucinations. This drug can make chorea worse, but is used for the rigid forms of HD.

References

Bonelli RM, Niederwieser G, Diez J, Gruber A, Költringer P. Pramipexole ameliorates neurologic and psychiatric symptoms in a Westphal variant of Huntington's disease. Clin Neuropharmacol 2002;25(1):58-60. PubMed abstract

Racette BA, Perlmutter JS. Levodopa responsive parkinsonism in an adult with Huntington's disease. J Neurol Neurosurg Psychiatry 1998 Oct;65(4):577-9. PubMed abstract

Magnet MK, Bonelli RM, Kapfhammer HP. Amantadine in the akinetic-rigid variant of Huntington's disease. Ann Pharmacother 2004;38(7-8):1194-6. PubMed abstract