Contact the person's Parkinson's disease specialist team if the following adverse effects of anti-parkinsonian medication occur, as alterations to the medication may be needed:

• Fibrotic reactions (such as cardiac valvulopathy and retroperitoneal fibrosis) related to ergot-derived dopamine agonists (bromocriptine, cabergoline, or pergolide) — see Drug monitoring.
• Nausea and vomiting related to anti-parkinsonian medication.
• Motor complications, including:
• Motor fluctuations.
• Dyskinesias.
• Dystonic or akathisia-related pain.
• Neuropsychiatric symptoms, including:
• Cognitive impairment.
• Confusion and vivid dreaming:
• As with psychotic symptoms, these symptoms can be caused by dopamine agonists and (less commonly) levodopa, selegiline, and amantadine, and by any medicine with an antimuscarinic action, including some antidepressants and antipsychotics.
• The causative drug may need to be withdrawn.
• Daytime hypersomnolence or excessive drowsiness.
• Impulse control and related disorders, including:
• Hypersexuality.
• Pathological gambling.
• Compulsive eating or buying.
• Punding — repetitive mechanical tasks, such as assembling or collecting.
• Dopamine dysregulation syndrome — compulsive dopaminergic drug use beyond that required for motor control.
• Psychotic symptoms.
• Sleep disturbance.
• Autonomic disturbances.
• Diarrhoea:
• May be caused by entacapone and tolcapone (catechol-O-methyltransferase inhibitors). Diarrhoea due to tolcapone tends to start several months after treatment is initiated, but no particular time-course has been identified with entacapone. The combination drug, Stalevo^®, contains entacapone.
• Dose reduction may be needed. However, diarrhoea is sometimes severe enough to warrant discontinuation.
• Excessive saliva (sialorrhoea).
• Excessive sweating (hyperhidrosis).
• Hypotension:
• Tends to occur at the start of treatment with levodopa, dopamine agonists, and selegiline.
• Can usually be managed by dose reduction and slower dose escalation.
• Peripheral oedema:
• May occur with amantadine and dopamine agonists, but is not dose dependent.
• Diuretics or discontinuation of the offending medication may be considered.
• Postural (orthostatic) hypotension.
• Weight loss.

The following adverse effects can initially be managed in primary care, but liaison with or referral to the person's Parkinson's disease specialist team may be needed if initial measures fail:

• Constipation.
• Nausea and vomiting unrelated to anti-parkinsonian medication.

These recommendations are pragmatic and based on an evidence-based review, Adverse events from the treatment of Parkinson's disease [Chou, 2008].