and rotated around the body to avoid the formation of nodules. Apomorphine is also available in a more acute dose as an autoinjector pen for emergency doses such as after a fall or first thing in the morning. Nausea and vomiting are common, and may require domperidone (an antiemetic). In a study evaluating the efficacy of dopamine agonists compared to levodopa, the results showed patients who took dopamine agonists were less likely to develop dyskinesia, dystonia, and motor fluctuations, although were more likely to discontinue therapy due to negative side effects such as nausea, edema, constipation, etc. MAO-B inhibitors Monoamine oxidase inhibitors (selegiline and rasagiline) increase the level of dopamine in the basal ganglia by blocking its metabolization. They inhibit monoamine oxidase-B (MAO-B) which breaks down dopamine secreted by the dopaminergic neurons. Therefore, reducing MAO-B results in higher quantities of L-DOPA in the striatum. Similarly to dopamine agonists, MAO-B inhibitors improve motor symptoms and delay the need of taking levodopa when used as monotherapy in the first stages of the disease, but produce more adverse effects and are less effective than levodopa. Evidence on their efficacy in the advanced stage is reduced, although it points towards them being useful to reduce fluctuations between on and off periods. Although an initial study indicated selegiline in combination with levodopa increased the risk of death, this has been later disproven. Metabolites of selegiline include L-amphetamine and L-methamphetamine (not to be confused with the more potent dextrorotary isomers). This might result in side effects such as insomnia. Another side effect of the combination can be stomatitis. Unlike other nonselective monoamine oxidase inhibitors, tyramine-containing foods do not cause a hypertensive crisis. Other drugs Some evidence indicates other drugs such as amantadine and anticholinergics may be useful as treatment of motor symptoms in early and late PD, but since the quality of evidence on efficacy is reduced, they are not first-choice treatments. In addition to motor symptoms, PD is accompanied by a range of different symptoms. Different compounds are used to improve some of these problems. Examples are the use of clozapine for psychosis, cholinesterase inhibitors for dementia, modafinil for day somnolence, and atomoxetine for executive dysfunction. A preliminary study indicates taking donepezil (Aricept) may help prevent falls in people with Parkinson's. Donepezil boosts the levels of the neurotransmitter acetylcholine, and is currently an approved therapy for the cognitive symptoms of Alzheimer's disease. In the study,