Caffeine drinking, cigarette smoking, and dopaminergic replacement therapy dose in Parkinson's disease

The objective of this study is to assess the effect of smoking and caffeine intake in the dosage of dopaminergic replacement therapy. Patients were recruited from the movement disorders clinic of the National Institute of Neurology and Neurosurgery in Mexico City. An interviewer-administered structured questionnaire was given to all subjects regarding their smoking and caffeine drinking habits. Dopaminergic replacement therapy information was collected and levodopa, dopamine agonists, and levodopa equivalent daily doses were calculated. 146 Parkinson's disease patients (50 % female) were included. All patients were on antiparkinsonian treatment, with a mean levodopa equivalent daily dose (LEDD) of 550.2 ± 408. Patients were stratified according to smoking and caffeine drinking status. 104 (71.2 %) of the patients were "never smokers", 33 (22.6 %) were "former smokers" and 9 (6.2 %) were "current smokers". 40 (27.4 %) patients reported no history of caffeine intake, 36 (24.7 %) were former consumers and 70 (47.9 %) were current caffeine drinkers. No association between LEDD and smoking or caffeine intake was found. A weak positive correlation (r = 0.22, p < 0.04) was found between the daily dose of pramipexole and the daily intake of caffeine. LEDD, levodopa daily dose and dopamine agonist daily dose were not related to smoking or caffeine intake status. We found a weak correlation between caffeine daily intake and pramipexole dose. Further prospective exploration is needed to address the interaction of concomitant A2A antagonism induced by caffeine intake and dopaminergic replacement therapy.