Dopamine D2 receptor antagonists (e.g., phenothiazines, butyrophenones, risperidone) and isoniazid may reduce the therapeutic effects of levodopa.
<Dopamine D2 receptor antagonists, effect, levodopa>, <phenothiazines, effect, levodopa>, <butyrophenones, effect, levodopa>, <risperidone, effect, levodopa>, <isoniazid, effect, levodopa>