Brain dopamine receptor stimulation and the relief of parkinsonism: Relationship between bromocriptine and levodopa

Abstract

The relationship between dopamine receptor stimulation by bromocriptine or levodopa and the relief of parkinsonism was studied in 24 patients with Parkinson disease. Bromocriptine, 30 mg daily for 20 weeks, elicited an improvement in the parkinsonian clinical features, but this was less than the subsequent improvement with levodopa and benserazide, 800 mg and 200 mg daily, respectively. There was a negative correlation between the pretreatment severity of the disease or changes in cerebrospinal fluid homovanillic acid (HVA) and improvement in parkinsonian disability during bromocriptine treatment. Futhermore, it was found that clinical improvement and HVA responses in the cerebrospinal fluid after dopamine receptor stimulation by bromocriptine may predict the clinical response to levodopa.

A Broad Spectrum of Prolactin Suppression by Bromocriptine in Hyperprolactinemic Women: A Study of Serum Prolactin and Bromocriptine Levels after Acute and Chronic Administration ofBromocriptine*

“…Bromocriptine now has an established therapeutic role in the suppression of postpartum lactation (2,3) in the treatment of hyperprolactinemia (4-7) and acromegaly (11)(12)(13). Although bromocriptine is used in the treatment of Parkinsonism, its advantages over levodopa remain a disputed issue (24,25). The rapid and profound lowering of PRL levels by bromocriptine has been well established.…”

Bromocriptine in Parkinson’s Disease: Results Obtained With High and Low Dose Therapy

“…Certainly some of the recently reported effectiveness of low dose bromocriptine is related to the present trend towards little or no levodopa decrease. The value of combination levodopabromocriptine therapy has been recognized (Caraceni et al, 1977) and it is accepted that bromocriptine is less potent than levodopa (Rinne and Marttila, 1978;Duvoisin et al, 1980). Kartzinel et al (1976b) demonstrated significant improvement with both low and high doses of bromocriptine; however, a better grade of response to high dose therapy has been more frequently reported (Parkes et al, 1976;Teychenne et al, 1978).…”

“…The low dose bromocriptine group included 89 different patients from four separate series (Grimes et al, 1983 a;Grimes and Hassan, 1981;Fahn et al, 1980;Lieberman et al, 1976 b). Response in de novo patients was assessed by reviewing the results obtained with 50 high dose (mean 70mg daily) patients reported by Lees and Stern (1983) and comparing them with 58 low dose (mean 19mg daily) patients collected from three separate series (Grimes et al, 1983 b;Teychenne et al, 1982;Rinne and Marttila, 1978).…”

Bromocriptine

“…Bromocriptine does appear to be effective in some Parkinson's disease patients at dosages of 15-90 mg per day, although there is not unanimous agreement on this.252,m,259,26,2M Patients who fail to respond or who have stopped responding to levodopa may have less likelihood of response to bromocriptine, but successful treatment of patients with diminishing response to levodopa has been documented.260,269-274 Likelihood of response may also be less if mental deterioration has as the severity of the illness increase^,^^^,^^^ and likelihood of response may have an inverse correlation to pretreatment HVA levels. 276 To avoid side effects, a 1 mg test dose followed by gradual increments over [6][7][8] weeks is r e c~m m e n d e d .~~~,~~ To avoid additive side effects from combining levodopa with bromocriptine, levodopa dosage needs to be decreased by about 125 mg for each 10 mg increase in bromocriptine.252 It may take several months to maximize response, and bromocriptine may potentially improve all or some of the symptoms of Parkinson's d i~e a s e .~…”