admin | 
02 13th, 2008| 
Summary - Behavioral disturbances in Parkinson’s disease (PD) are a common sourceof disability to both patients and their families, but there is a considerable controversy regarding their frequency and their neuropathological and neurochemical bases.
Since they are so common, the disorders associated with PD should be well recognized, and proper management by neurologists is required. The most frequent behavioral disturbances encountered in patients with PD are depression, anxiety, cognitive impairment and dementia.
Also frequent are sleep disorders such as sleep fragmentation, REM sleep behavior disorder, insomnia and altered dreaming.
The most troublesome situations come from drug-induced psychiatric states, such as delusional states, hallucinations, paranoid ideation, delirium, and confusion.
The treatment of these behaviors is reviewed here.
In the general population, benzodiazepines are the most commonly used drugs to improve anxiety ymptoms. Lorazepam, a relatively short acting drug, is usually well tolerated in older patients. Diazepam or hlordiazepoxide have longer half lives, but they are poorly tolerated by older patients and patients with impaired renal function. When discontinuing their use, these drugs must be tapered over a two week period. Barbiturate drugs are not commonly used in PD patients because of their excessive sedative side effects. Drugs which are active in the autonomic nervous system, such as diphenhydramine or hydroxyzine, can be useful to treat symptoms of autonomic dysfunction such as wet and cold hands, tachycardia, tachypnea, dry mouth, diarrhea and parestesia in hands or feet.
Beta-blockers, which can be used for the treatment of postural tremor or dyskinesia in PD, have a mild effect over anxiety related tachycardia. They should not be prescribed in patients with a heart block or impaired respiratory function.
Depression is almost as frequent as anxiety in PD. Once detected, depression should be treated promptly by the physician because of its clinical implications and the repercussion in the quality of the patient’s life.
Furthermore, there is evidence for an association between depression and dementia in PD.
L-dopa treatment seems to have only a short positive effect on depression in PD, presumably due to the amelioration of motor symptoms. Most patients with depression continue to be depressed one to six years after starting L-dopa therapy.
Since the overall efficacy of most antidepressants is similar, the clinical utility of a given drug often depends on the presence or absence of particularly troublesome side effects. Serotonin re-uptake inhibitors, such as sertraline, fluoxetine, paroxetine and citalopram among others, have certain advantages over the classic tricyclic antidepressants with regard to their side effects spectrum. The anticholinergic features typically associated with tricyclics, such as dry mouth and constipation, are less frequent with these drugs. Postural hypotension and sedation are also infrequent, but other important side effects have been reported.
Most of the common side effects of serotonin reuptake inhibitors include anxiety (present in 10-15% of patients), insomnia (in 10-30% of patients), restlessness, weight loss, anorexia, somnolence, postural tremor, light-headedness, gastrointestinal disturbances, allergic reactions, and libido disturbances in men. In addition, the most common side effects of classical tricyclic antidepressants include anticholinergic effects (dry mouth, constipation, urinary retention, blurred vision), anti-histaminic effects, excessive sedation, and anti-adrenergic effects such as postural hypotension, tachycardia or anxiety. There have also been several reports concerning the use of serotonin re-uptake inhibitors in PD that have pointed out the possibility of a worsening of motor symptoms during treatment with fluoxetine and paroxetine.
However, these symptoms were found improve after withdrawal of the drug. Fluoxetine has also been associated with the induction of akathisia. However, no alteration of motor condition was found in 14 PD patients treated with a daily dose of 20 mg of fluoxetine. Another study with 23 PD patients treated with fluoxetine and deprenyl, showed no adverse effects.
In conclusion, there are very few single case reports that have suggested that serotonin re-uptake blockers worsen the motor condition in PD. Moreover, these drugs show less important side effects than tricyclic antidepressants, especially in the elderly population, and should therefore be regarded as the first choice drugs in the treatment of depression in PD. They should however be used cautiously until controlled studies have been carried out. Read the rest of this entry »