Modulation of abnormalities in renal haemodynamics and vasoactive mediators by nifedipine in patients with psoriasis on low-dose cyclosporin

Ten patients with psoriasis received a 3-month course of cyclosporin(2.5 mg/kg/day) followed by a 3-month washout period, beforecommencing a 3-month course of cyclosporin and nifedipine SR20 mg b.d. Serial haemodynamic and biochemical measurementswere performed before, during, and after treatment. Total renalblood flow (RBF) was measured following an intravenous injectionof [^99mTc]-DTPA based on a renographic analysis of the first-passeffect in the kidneys, and GFR was estimated from the subsequentclearance of this radiotracer. A significant individual changein RBF or GFR was taken as 25/ and 20/ respectively. Simultaneousassays of the circulating vasoactive mediators renin, aldosterone,angiotensin II, and atrial natriuretic peptide were performed.Two patients withdrew from the study because they could nottolerate nifedipine, leaving eight for complete analysis. Thesignificant reductions in RBF and GFR which occurred on cyclosporinalone (P<0.05; ANOVA) did not occur with added nifedipine.Four months after this second course, RBF and GFR had recovered.The response to nifedipine was, however, variable and unpredictable.Of the four patients to show a significant decline in GFR oncyclosporin alone, only two showed a significant improvementon the combined therapy. Of the six patients who showed a significantdecline in RBF on cyclosporin alone, only four showed benefitfrom the added nifedipine. Nifedipine suppresses the increasein blood pressure which occurred on cyclosporin alone. The circulatingconcentration of angiotensin II was significantly less on cyclosporinand nifedipine than on cyclosporin alone (P<0.05; Student'st test). There was a significant reduction in serum aldosteroneafter cyclosporin administration (P<0.05; ANOVA). Plasmarenin activity did not change. There were statistically significantincreases in ANP on cyclosporin and nifedipine (P<0.05; ANOVA). The interaction between nifedipine and cyclosporin on the glomerularmicrocirculation and on the release of angiotensin II by thenormal innervated kidney can either reduce or increase haemodynamictoxicity. Regardless of haemodynamic improvement, nifedipinedoes not correct all the hormonal changes.     

The cardiovascular effects of oral nifedipine and nicardipine: A double-blind comparison in healthy volunteers using transthoracic bioimpedance cardiography

The cardiovascular effects of single oral doses of nifedipine (5 and 10 mg) and nicardipine (20 and 30 mg) were compared in a placebo controlled double-blind crossover study involving 8 healthy male volunteers. Two hours following drug administration stroke volume and cardiac index were measured non-invasively using transthoracic electrical bioimpedance cardiography during passive tilting, graded bicycle exercise, and recovery from exercise. Two separate experiments were performed in the absence of active drug to allow the reproducibility of the measurements to be assessed. Coefficients of variation (within experiment/between experiments) for cardiac index were 7.0%/19.9% at rest and 11.5%/9.3% at 180 W exercise. Both nifedipine and nicardipine increased stroke volume and cardiac index and reduced total peripheral resistance (mean blood pressure/cardiac index) at all times in the experiment. Reductions in peripheral resistance were similar for nifedipine 10 mg and nicardipine 20 mg but in these doses slightly larger increases in heart rate were produced by nifedipine, and in stroke volume and cardiac index with nicardipine. The study shows that the cardiovascular effects of nifedipine and nicardipine can be detected using impedance cardiography which is a simple, safe, and inexpensive technique. The differences between the effects of the two drugs were small. Although some were of statistical significance and are consistent with a less marked cardiodepressant effect for nicardipine, the clinical importance of these observations is uncertain. Further studies to examine the effect of oral nifedipine and nicardipine in patients with impaired ventricular function may be helpful in clarifying this tissue.     

硝苯啶光稳定性及其光解产物的研究

研究表明硝苯啶的结晶态对光的稳定性大于溶液态。介绍了一种分离光解产物的方法.     

吡那地尔与硝苯啶对大鼠离体工作心脏的影响

在大鼠离体工作心脏上，ＡＴＰ敏感性Ｋ＋通道开放剂吡那地尔（ＰＩＮ）１～１０μｍｏｌ／Ｌ可加快心率，１０μｍｏｌ／Ｌ产生负性肌力作用，使主动脉射量略有下降，但不影响冠脉流量。０．１μｍｏｌ／Ｌ二氢吡啶类钙拮抗剂硝苯啶（ＮＩＦ）可减慢心率，降低主动脉射量，１．０μｍｏｌ／ＬＮＩＦ有明显的负性肌力及负性频率作用，主动脉射量显著下降，冠脉流量变化不明显。提示ＰＩＮ及ＮＩＦ均可直接作用于心脏，但二者的作用性质及作用强度不同，ＰＩＮ有较轻的正性频率和负性肌力作用，ＮＩＦ有明显的负性频率和负性肌力作用     

Evaluation of gingival and periodontal conditions following causal periodontal treatment in patients treated with nifedipine and diltiazem*

Abstract It is established that phenytoin, cyclosporin and some calcium antagonists produce gingival overgrowth, but it is not known how this condition may respond to causal periodontal treatment. In order to find out, a longitudinal study was carried out, over a year, comparing a group of patients who were given nifedipine (NG, n= 18) and another group who were given diltiazem (DG. n= 13) with 2 others: one comprised cardiopathic patients who took no calcium antagonists (CG, n= 12) and the other contained patients who were medically healthy. with moderate periodontitis (HG, n= 12). On their basal visit, they were examined and instructed in oral hygiene, and then given causal periodontal treatment, being seen again at 4 and 8 months, when hygiene instructions were reinforced. They were seen for the last time at 12 months, when they were again examined. Groups NG and DG, on their basal visit, showed larger gum size than groups HG and CG. which was statistically significant; on their final visit, these differences remained only at the interproximal level. The number of patients with gingival overgrowth-taking the average of group HG as a minimal value-was much higher in groups CG (92%). DG (100%) and NG (89%) on the basal visit; on the final visit, the differences remained only in groups DG (85%) and NG (83%). The probing pocket depth reduction was much greater in groups HG and CG than in DG and NG. basically due to a greater gaining on clinical attachment level. The % of sites in which the pocket depth improved by more than 2 mm was 39.8% in HG, 54.5% in CG, 23.7% in DG and 28.7% in NG. The % of sites where the attachment gain by more than 2 mm was 46.2% in HG, 55.5% in CG, 22.8% in DG and 21.4% in NG. The amount of plaque and bleeding on probing, which was similar in all groups on the basal visit, decreased throughout the study, especially between the basal and 2nd visit in groups HG and CG. We have demonstrated that patients that take nifedipine and diltiazem show a larger gum size and their response to causal periodontal treatment is poorer than in the healthy and the cardiac groups.     

Nifedipine-prazosin interaction in patients with essential hypertension

Summary In an acute, double-blind, crossover study on 12 patients with essential hypertension, the interaction between nifedipine and prazosin was investigated in the supine position. The effectiveness of the combination of the two active drugs was greater than the combination of either of the drugs plus placebo. The effect of nifedipine was not modified by prazosin pretreatment; however, the effect of prazosin was partly inhibited, i.e., delayed, by nifedipine pretreatment. Therefore, giving prazosin as a first drug and nifedipine as the second drug seems to be a better approach than the reverse.