Postural hypotension with levodopa

When used along with levodopa, the plasma half life of levodopa is prolonged and dose may be markedly reduced. Also the most common side effect i.e. nausea and vomiting are not prominent and cardiac complications are minimized. It has no effect on involuntary movements, behavioral abnormalities and postural hypotension. 

Postural hypotension is common and often asymptomatic, and tends to diminish with continuing treatment. Hypertension may also occur, especially in the presence of nonselective monoamine oxidase inhibitors or sympathomimetics or when massive doses of levodopa are being taken. 

Adverse effects Diarrhea is the most common side effect of tolcapone. As expected, /evocfopa-related adverse effects increase when tolcapone is added. These include postural hypotension, nausea, sleep disorders, anorexia, dyskinesias, and hallucinations. Most seriously, fulminating hepatic necrosis is associated with tolcapone use. Baseline and frequent, regular determinations of hepatic serum enzymes are suggested by the manufacturer. Any elevations above normal are cause for discontinuation. Because of the hepatotoxicity, tolcapone should only be used as an adjunct in patients on levodopa/carbidopa who are experiencing symptom fluctuations. 

Supraventricular extra beats have rarely been reported after low doses of ropinirole and have also been reported after pergolide and levodopa (1). Symptomatic postural hypotension has occurred after even low oral doses of ropinirole (2-5), related to peripheral dopaminergic activity. Hypotensive effects occur within 3 minutes of standing, usually between 2 and 4 hours after an oral dose, associated with nonspecific malaise (2). Dizziness occurred in up to 40% of patients in clinical trials. Related symptoms include faintness, malaise, and yawning (2). Bradycardia has occasionally accompanied postural hypotension (4). Syncope has been reported. 

Toxicity Gastrointestinal effects include anorexia, nausea, and vomiting. Cardiovascular effects commonly include postural hypotension cardiac arrhythmias may also occur. Dyskinesias may occur with abnormal movements similar to those caused by levodopa. Behavioral effects include confusion, hallucinations, and delusions these occur more commonly with bromocriptine and pergolide than with levodopa. Like levodopa, bromocriptine and pergolide are contraindieated in patients with a history of psychosis. Miscellaneous ei ot-related effects with bromocriptine inelude pulmonary infiltrates and erythromelalgia. 

Early in the treatment of PD with levodopa the client may have postural hypotension, but hypertension is not associated with levodopa. 

Side effects similar to those previously reported (SED VIII, p. 322) have been seen in further studies. I en substituting bromocriptine 20—75 mg daily for levodopa in the treatment of parkinsonism 19 patients improved but 7 could not tolerate the change. There were 3 cases of syncope, 2 of hallucinations and one each of emesis, somnolence or slowing of the pulse rate with faintness (26 -). Volunteers given bromocriptine appear to be most sensitive with the first doses when they tend to develop nausea, vomiting or postural hypotension. Patients with raised levels of serum prolactin and acromegaly are less likely to have early side effects and women immediately post-partum are most resistant (27 ). 

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