Opposite effects of nicotinic acid and pyridoxine on systemic prostacyclin, thromboxane and leukotriene production in man.

The effects of nicotinic acid (2500 mg orally during 12 hr) and pyridoxine (300 mg orally twice daily for seven days) on the excretion of urinary 2,3-dinor-6-ketoprostaglandin F1alpha, 11-dehydrothromboxane B2 and leukotriene E4, the markers of systemic prostacyclin, thromboxane A2 and cysteinyl leukotriene production, respectively, were investigated in healthy male volunteers (n=6-8). Nicotinic acid increased 11-dehydrothromboxane B2 and leukotriene E4 excretions to 2.6- and 2.0 times the initial values (P<0.05), respectively. In the volunteers treated with pyridoxine, 11-dehydrothromboxane B2 and leukotriene E4 excretions were decreased to 70% (P<0.05) and 65% (P<0.01) of the initial values, respectively, but the excretion of 2,3-dinor-6-ketoprostaglandin F1alpha was increased 1.7 times (P<0.01). The results suggest that nicotinic acid increases thromboxane and leukotriene synthesis which may not be beneficial for patients with cardiovascular diseases or asthma. In contrast, the increase in prostacyclin production and the inhibition in thromboxane and leukotriene synthesis by pyridoxine might be beneficial in disorders where the production of prostacyclin is decreased and the formation of thromboxane and cysteinyl leukotrienes is enhanced.

The quality and characteristics of clinical drug study notifications reviewed by the regulatory agency in Finland.

The aim of our study was to investigate the validity of clinical drug study notifications reviewed by the regulatory agency in Finland during the 1990s. (In practice, the notification is equivalent to tacit authorization, which the agency has full powers to revoke before it takes effect.) All clinical drug studies reviewed by the agency during the years 1992, 1994, 1996, and 1998 were studied retrospectively. The main measurements used were the number of studies with no objection to start; the number and type of questions raised; the profile, phase, and type of study; and the study design. Additionally, the studies approved by two ethics committees of university hospitals during the same years were cross-checked to see whether the agency was notified of them in accordance with the national regulations. In total, 1174 study notifications were reviewed. Most studies were international (52%), phase III (46%), placebo-controlled with/without active control (35%) investigations of new chemical entities (38%) and were carried out in university hospitals (63%). The regulatory agency had no objections or questions regarding 55% of the notifications; 37% of the studies were permitted to begin after a clarification; 5% had to be clarified a second time; and 3% were rejected. Most questions dealt with subject information. Out of the 1140 permitted studies, 8% were later canceled or prematurely terminated as reported by the applicant. Altogether 71% of the studies that had been reviewed and approved by the ethics committees were reported to the authorities before commencement. Study completions were rarely reported. Most of the clinical drug studies planned in Finland are large international studies to investigate new chemical entities. More than half of the notifications are valid according to the regulatory authorities. Not all studies, nor the majority of study completions, are reported to the authority, though according to the regulations they should be so reported. The results show that better compliance with regulatory requirements is needed, and the contents of submitted documents should be improved to gain better Good Clinical Practice compliance. The regulatory agencies and committees that review clinical study documents should improve their current practices by a more specific division of responsibilities.