Bromocriptine for parkinsonism

Bromocriptine is a D2 agonist its structure is shown in Table 16-6. This drug has been widely used to treat Parkinson s disease in the past, but is now rarely used for this purpose, having been superseded by the newer dopamine agonists. Bromocriptine is absorbed to a variable extent from the gastrointestinal tract peak plasma levels are reached within 1-2 hours after an oral dose. It is excreted in the bile and feces. The usual daily dose of bromocriptine for parkinsonism varies between 7.5 and 30 mg. To minimize adverse effects, the dose is built up slowly over 2 or 3 months from a starting level of 1.25 mg twice daily after meals the daily dose is then increased by 2.5 mg every 2 weeks, depending on the response or the development of adverse reactions. 

Retroperitoneal fibrosis (SEDA-12, 123) (18) and pulmonary fibrosis (SEDA-11, 130) during treatment with high doses of bromocriptine have been observed. The drug s structural relation to methysergide clearly has to be kept in mind. Pleural thickening and effusions can be present in up to 6% of patients treated with bromocriptine for Parkinson s disease, and this is related to duration of exposure and cumulative dose (19). The author recommended drug withdrawal in these patients. However, withdrawal does not always lead to complete resolution of the lesions (20). 

Darkening of the sweat has been described (43). Darkening of the white hair of a patient who was taking levodopa in combination with bromocriptine for Parkinson s disease has been reported (SEDA-15,133). 

A 73-year-old man taking levodopa/benserazide and bromocriptine for Parkinson s disease was given lansoprazole 15 mg daily to treat reflux oesophagitis. Two days later, the patient exhibited akinesia (more motor difficulties and slowness in movements) associated with frequent falls. Lansoprazole was discontinued, with disappearance of the symptoms the day after. About 3 months later the patient was prescribed omeprazole 20 mg daily, which caused no aggravation of Parkinson s disease over the following 6 months. 

Clarke CE, SpeUer JM. Pergolide versus bromocriptine for levodopa-induced complications in Parkinson s disease. Cochrane Database Syst Rev 1999. 

Current drug-based therapies for Parkinson s disease are palliative therapies, i.e. they relieve the symptoms, but do not cure the disease. One of the current and expanding therapies is treatment with dopamine D2/D3 receptor agonists. There are a number of such therapeutics, e.g. bromocriptine, pergolide, apomorphine, ropinirole, and pramipexole. 

Bromocriptine is considered first line treatment for Parkinson s. It is effective in conjunction with a cholinergic-lowering drug (e.g., amantadine), and is also used as monotherapy in patients undergoing a drug holiday from therapy with L-dopa. It may also be used as a partial replacement for L-dopa, allowing the dose of L-dopa to be lowered. Bromocriptine is also used to ameliorate on-off phenomena. 

Those for the D2 receptor (e.g. bromocriptine) have a particular value in the treatment of Parkinson s disease by reproducing the effects of the dopamine lost through degeneration of the nigrostriatal tract (Chapter 15). They are also used to reduce the undesirable effects of prolactinaemia (high plasma prolactin), such as amenorrhoea and galactorrhoea. 

The answer is b. (Hardman, pp 282—283J Central dopamine receptors are divided into Dt and D2 receptors. Antipsychotic activity is better correlated to blockade of D2 receptors. Haloperidol, a potent antipsychotic, selectively antagonizes at Dz receptors. Phenothiazine derivatives, such as chlorpromazine, fluphenazine, and promethazine, are not selective for D2 receptors. Bromocriptine, a selective D2 agonist, is useful in the treatment of parkinsonism and hyperprolactinemia. It produces fewer adverse reactions than do nonselective dopamine receptor agonists... 

Bromocriptine mesilate is marketed as Parlodel capsules (10 mg for the treatment of Parkinson s disease) and tablets (2.5 mg as lactation suppressor). Both forms have proved stable at least for 4 years when stored at ambient temperature in amber glass bottles (22). ... 

Bromocriptine is a dopamine agonist acting by direct stimulation of the dopamine receptors. In Parkinson s disease, it is reserved for use in patients who are intolerant to levodopa or in whom levodopa alone is not sufficient. Orphenadrine is an antimuscarinic indicated in Parkinson s disease. Antimuscarinics tend to be more effective than levodopa in targeting tremor rather than rigidity and bradykinesia. Moclobemide is an antidepressant referred to as a reversible monoamine oxidase inhibitor (RIAAA) type A. 

Bromocriptine, a dopaminomimetic that is a dopamine D2 receptor agonist, possesses expressed antiparkinsonian activity. It is used for treating all phases of idiopathic and post-encephalic Parkinsonism. However, it has a number of undesirable side effects, even causing mental disturbances in long-term use. The most common synonyms are parlodel, bromergon, and others. 

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