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Teva Recalls ‘Super Potent’ Parkinson’s Disease Medication
Teva Pharmaceutical Industries has recalled one lot of its generic Parkinson’s disease (PD) combination medication carbidopa/levodopa because it may contain too much of an active pharmaceutical ingredient.
The company indicated that the recall, which has been deemed Class II, involved 3,881 bottles of carbidopa/levodopa 25 mg/100 mg. Teva also indicated that stability testing revealed that the recalled carbidopa/levodopa may be what the drug maker described as “super potent.”
The voluntary recall is for the entire U.S.
Teva’s carbidopa/levodopa combination is equivalent to Sinemet tablets (Merck). The 25 mg/100 mg generic tablets were approved by the FDA in August 1992.
PD is a progressive, neurodegenerative disorder of the extrapyramidal nervous system affecting the mobility and control of the skeletal muscular system. Its characteristic features include resting tremor, rigidity, and bradykinetic movements.
Current evidence indicates that the symptoms of PD are related to the depletion of dopamine in the corpus striatum. The administration of dopamine is ineffective in the treatment of PD apparently because it does not cross the blood–brain barrier. However, levodopa, the metabolic precursor of dopamine, does cross the blood–brain barrier and presumably is converted to dopamine in the brain. This is thought to be the mechanism whereby levodopa relieves the symptoms of PD.
When levodopa is administered orally it is rapidly decarboxylated to dopamine in extracerebral tissues so that only a small portion of a given dose is transported unchanged to the central nervous system (CNS). For this reason, large doses of levodopa are required for an adequate therapeutic effect, and these doses may often be accompanied by nausea and other adverse reactions, some of which are attributable to dopamine formed in extracerebral tissues.
Carbidopa inhibits decarboxylation of peripheral levodopa. It does not cross the blood–brain barrier and does not affect the metabolism of levodopa within the CNS.