Vomiting bromocriptine

Parkinsonian patients receiving the dopamine precursor, levodopa or dopamine receptor agonists, such as bromocriptine and apomoiphine may experience nausea and vomiting due to stimulation of dopamine D2 receptors in the CTZ. 

Bromocriptine (Parlodel ) 0.625-1.25 mg/day at bedtime 1.25 mg increments at 1 -week interval 2.5-1 5 mg/day 40 mg/day 2 to 3 divided doses per day Dizziness, headache, syncope, nausea, vomiting, Gl cramps, orthostatic hypotension ... 

A 28-year-old man received interferon alfa (5 MU/day for 28 days) for chronic hepatitis B. At the end of treatment he developed a slight parkinsonian gait, and 8 days later had a fever with vomiting, insomnia, restlessness, and raised serum creatine kinase activity (4946 IU/1). He had severe akathisia with psychomotor excitement and parkinsonism. Despite treatment with clonazepam, thioridazine, propranolol, trihexyphenidyl, and bromocriptine, his condition progressively worsened. He was finally given intravenous levodopa for 8 days and recovered dramatically within the next few days. 

Vomiting is triggered in the chemoreceptor trigger zone of the medulla, and nearly all dopamine receptor agonists (e.g. bromocriptine), and agents that increase dopamine in the brain (e.g. levodopa), cause vomiting. Conversely, many dopamine receptor antagonists (e.g. metoclopramide, and phenothiazines, e.g. chlorpromazine and prochlorperazine) have antiemetic activity. 

A patient undergoing cancer chemotherapy is vomiting frequently. A drug that might help in this situation is (A) Bromocriptine Cimetidine Ketanserin Loratadine Ondansetron... 

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. 

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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