Proper treatment of tremor in any clinical setting depends on correct diagnosis. Essential, or familial, tremor is symptomatic with movement and involves the limbs, head and voice. Parkinson's disease tremor occurs at rest, involves the jaw and limbs and is associated with bradykinesia, rigidity and falling. Parkinson's disease is treated with a number of medications, but levodopa, a dopamine precursor, is considered most effective. Other therapies in the early stages of Parkinson's disease may include neuroprotective agents, dopamine agonists, dopamine reuptake inhibitors, anticholinergics and/or amantadine. Polypharmacy is often necessary to minimize or avoid drug side effects.