Biologic rhythms and Parkinson's disease: a chronopharmacologic approach to considering fluctuations in function.

The existence of circadian rhythms and their implication in many pathologic processes have been underlined in several diseases but have not been evaluated in Parkinson's disease. The aim of this paper is to review diurnal variations of clinical, biologic, or experimental factors described with Parkinson's disease. Clinical data often report daily fluctuations of motor activity pattern, but the effect of the stage of the disease and the respective roles of drugs are difficult to evaluate. Sleep disturbances in Parkinson's disease patients also reveal alterations of circadian rhythms. Autonomic dysfunction, described in Parkinson's disease, reveals numerous alterations in circadian regulations including loss of circadian rhythm of blood pressure, increased diurnal blood pressure variability, and postprandial hypotension. Many biologic indices such as cortisol, catecholamines, and melatonin are also altered. Circadian rhythms in dopaminergic systems as well as possible daily fluctuations in kinetics of drug treatments are likely involved in such variations. Few clinical studies have been devoted to circadian patterns of drug response. As for other diseases where biologic rhythms are concerned Parkinson's disease therapy may be influenced by further understanding of circadian influence.

Pharmacokinetics of diethylcarbamazine after single oral dose at two different times of day in human subjects.

In most Wuchereria bancrofti and Brugia malayi infections, the microfilaria are found in the blood in greatest number between 10 p.m. and 2 a.m., indicating that chronotherapy may be beneficial in treating such infections. This study reports the influence of time of administration on the pharmacokinetics of diethylcarbamazine (DEC) in healthy volunteers. The study was conducted in 12 healthy volunteers by administering a 150 mg single oral dose of diethylcarbamazine citrate at 0600 or 1800 h in a balanced crossover design with the approval of an institutional ethics committee. The subjects fasted for about 10 hours before and 3 hours after drug treatment. Blood samples were collected at predetermined time intervals, and the drug content in the serum was estimated using HPLC with an electrochemical detector. Pharmacokinetic analysis was performed using noncompartmental methods employing WinNonlin (version 3.1), and the means of various pharmacokinetic parameters were compared for any dosing time-related changes using a paired t-test at a probability level of 95%. The mean +/- SD values of pharmacokinetic parameters of DEC for the treatments at 0600 versus 1800 h were as follows: Cmax, 500+/-227 versus 637+/-401 ng/ml; tmax, 2.3+/-0.7 versus 2.7+/-1 h; Ka, 2.23+/-0.72 versus 1.96+/-0.97 h(-1); t1/2, 14.6+/-6.7 versus 11.4+/-4.9 h; AUC0-t, 5,334+/-1,853 versus 6,901+/-4,203 ng x h/ml; AUC0-infinity, 5,840+/-1,922 versus 7,220+/-4,205 ng x h/ml; CL/F, 36,058+/-19,011 versus 32,189+/-25,293 ml/h/kg; Vd/F, 570+/-225 versus 533+/-447 L; and MRT 17.7+/-5.9 versus 15.3+/-5.2 h. None of the parameters was significantly changed (p > 0.05) as a function of time of administration.

Circadian variation of basal total vascular tone and chronotherapy in patients with vasospastic angina pectoris.

Vasospastic angina pectoris (VSA) is an anginal attack which occurs characteristically between night and early morning. The aim of this study was to clarify the cause of VSA. The subjects consisted of 16 patients with VSA, 18 patients with effort angina (EAP) and 15 healthy individuals, who were used as the control group. Subjects were attached to an ambulatory blood pressure monitor and a non-invasive continuous cardiac output monitor concurrently, over a 24-hour period. Mean blood pressure (MBP), and cardiac index (CI) were measured. Then basal total vascular tone (TVT) was calculated as follows: basal TVT = (MBP/CI) x 1,332 dyne/sec/cm5. The decrement of CO was greater during sleeping hours as compared with the decrement of the MBP in the VSA group. Nocturnal basal TVT was significantly greater in the VSA group than in the EAP group or the control group. The increased nocturnal basal TVT was significantly suppressed by long acting calcium antagonists to the level of the EAP and the control groups. The treatment also decreased the frequency of ischemic attacks.

Chronotherapy in traditional Chinese medicine.

The circadian rhythm of illness has been emphasized for thousands of years in Traditional Chinese Medicine (TCM), using this knowledge to schedule therapies such as acupuncture during appropriate hours of the day. This paper reviews the time periods (two hour segments) that apply to each organ system according to TCM (lungs, large intestine, stomach, heart, kidneys and liver), and elaborates on how recent medical research has found similar relevant biorhythms in these very same organ systems.