František Perlík

Unfortunately, original article has been published without acknowledgement section.

Dopamine was shown to induce mydriasis by excitation of alpha-adrenergic receptors at the dilator pupillae muscle. Pupilla diameter may thus serve as an indirect measure of peripheral pharmacokinetics of l-DOPA and dopamine. The aim of this study is to evaluate the effect of l-DOPA dosage on pupillometric parameters in Parkinson’s disease (PD) patients. Sixteen PD patients and 14 healthy control subjects (CS) were studied. The statistical analysis revealed significant differences between CS and PD patients for the mean maximum and minimum pupil diameters (p = 0.017, p = 0.028, respectively), with higher values found in PD. Moreover, a significant dose–response relationship was found between the maximum pupil diameter and both the morning l-DOPA dose (R ² = 0.78) and the total daily l-DOPA dose (R ² = 0.93). A sigmoid-shaped curve best describes the dose–response relationship, with a ceiling effect at about 400 mg l-DOPA daily dose. In conclusion, measuring pupillometric parameters represents a sensitive tool for non-invasive evaluation of the peripheral effect of l-DOPA, especially with daily doses below 400 mg l-DOPA.

In this open-label, laboratory-blinded, 2-way single dose study in 24 volunteers of both sexes we found that (1) nabumetone reaches mean C_max ± SD of 0.56 ± 0.20 mg·L⁻¹ at mean t_max of 8.63 ± 7.05 hours, and mean area under the curve (AUC)_last of 18.07 ± 7.19 h·mg·L⁻¹; (2) there are no statistically significant differences between both sexes in pharmacokinetics of nabumetone; (3) 6-methoxy-2-naphthylacetic acid (6-MNA) reaches higher AUC_last in men compared with women (mean ± SD, 721.23 ± 185.53 h·mg·L⁻¹ and 545.27 ± 97.69 h·mg·L⁻¹, respectively; P = 0.013); (4) there is lower 6-MNA clearance in men (0.65 ± 0.22 L·h⁻¹) in comparison with women (0.88 ± 0.18 L·h⁻¹, P = 0.019), (5) intersubject variability of nabumetone and 6-MNA is between 35%–45% and 10%–30% for all assessed pharmacokinetics parameters (AUC_last, C_max, partial AUC values); (6) intrasubject variability (ISCV) for AUC_last is low, 15.59% and 6.40% for nabumetone and 6-MNA, respectively, (7) ISCV for C_max is 13.66% and 5.42% for nabumetone and 6-MNA, respectively. Nabumetone thus belongs to compounds with low to moderate ISCV and therefore this product is expected to produce consistent effects in clinical practice.

Niacin was the first hypolipidemic drug to significantly reduce both major cardiovascular events and mortality in patients with cardiovascular disease. Niacin favorably influences all lipoprotein classes, including lipoprotein[a],and belongs to the most potent hypolipidemic drugs for increasing HDL-C. Moreover, niacin causes favorable changes to the qualitative composition of lipoprotein HDL. In addition to its pronounced hypolipidemic action, niacin exerts many other, non-hypolipidemic effects (e.g., antioxidative, anti-inflammatory, antithrombotic), which favorably influence the development and progression of atherosclerosis. These effects are dependent on activation of the specific receptor HCA2. Recent results published by the two large clinical studies, AIM-HIGH and HPS2-THRIVE, have led to the impugnation of niacin’s role in future clinical practice. However, due to several methodological flaws in the AIM-HIGH and HPS2-THRIVE studies, the pleiotropic effects of niacin now deserve thorough evaluation. This review summarizes the present and possible future use of niacin in clinical practice in light of its newly recognized pleiotropic effects.

Genetic factors may contribute to the differential response to opioids. The aim of this study was to evaluate the association between polymorphisms of µ1-opioid receptor gene OPRM1 (rs1799971), and P-glycoprotein transporter gene ABCB1 (rs1045642, rs2032582), and piritramide efficacy under postoperative patient-controlled analgesia (PCA). In 51 patients, OPRM1 variant was associated with decreased efficacy in early postoperative period evidenced by sum of pain intensity difference in the 0-6 h postoperative period (SPID0-6), (F=3.27, p=0.029). Mean (SD) SPID0-6 was observed in the 118AA genotype 22.9 (6.1) mm, which was significantly higher from the 118GG genotype 10.0 (4.4) mm, p=0.006. The lowest cumulative dose was recorded in 118AA genotype 19.1 (9.8) mg, which was significantly less than in the 118GG genotype group 36.6 (6.1) mg, p=0.017. Opioid–induced adverse effects were observed in 11, 30, and 100 % of patients in 118AA, 118AG, and 118GG genotype groups, respectively (p<0.05). Piritramide efficacy and safety was not significantly affected by ABCB1 (rs1045642, rs2032582) polymorphisms. Variant OPRM1 118G allele is associated with decreased acute postoperative pain relief after piritramide. Decreased efficacy leads to higher drug consumption under PCA settings, which however, does not fully compensate insufficient pain relief, but increases incidence of adverse effects.

Niacin is considered to be a powerful drug for the treatment of lipid and lipoprotein abnormalities connected with "residual cardiovascular risk", which persist in high-risk patients even when the target goals of LDL-C are achieved with statin therapy. Recent large randomized clinical studies - AIM-HIGH (Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides) and HPS2-THRIVE (Heart Protection Study 2-Treatment of HDL to Reduce the Incidence of Vascular Events) - delivered some disappointing results, leading to the conclusion that no further benefit (decreased parameters of cardiovascular risk) is achieved by adding niacin to existing statin therapy in patients with high cardiovascular risk. Moreover, in these studies, several adverse effects of the treatment were observed; therefore, niacin treatment for hypolipidemias is not recommended. In this paper, we analyze the mechanisms underlying the hypolipidemic and antiatherogenic effects of niacin as well as some limitations of the designs of the AIM HIGH and HP2-THRIVE studies. We also provide the possibilities of rational usage of niacin for specific types of dyslipidemias.

Impact of MDR1 genetic polymorphisms on postoperative piritramide analgesia

Aim: CYP2C8 represents 7% of the hepatic cytochrome system and metabolizes around 5% of drugs in phase I processes. It also plays a significant role in metabolism of endogenous compounds. More than 20 single-nucleotide polymorphisms (SNPs) have been noted, mainly in exons 3, 5, and 8. The most studied SNPs may lead to decreased enzyme activity and may have impact on drug metabolism. Variant alleles are called CYP2C8*2 (I269F), CYP2C8*3 (R139K, K399R), and CYP2C8*4 (I264M). Our aim was to investigate the frequency of major functional SNPs among the Czech population. Material and methods: DNA was isolated from whole blood of 161 healthy, young, and unrelated subjects (94 men and 67 women, aged from 23 to 28 years). The genotypes of polymorphic positions CYP2C8*2 , CYP2C8*3 (G416A, A1196G), and CYP2C8*4 were determined by polymerase chain reaction-restriction fragment length polymorphism. Results and conclusion: Observed allele frequencies were 10.9%, 5.9%, and 0.3% for the alleles CYP2C8*3 , CYP2C8*4 , and CYP2C8*2 , respectively. Both CYP2C8*3 (G416A, A1196G) alleles have been found in complete linkage disequilibrium. The allele distribution complies well with Hardy-Weinberg equilibrium. Allele frequencies of functionally important CYP2C8 variants in the Czech population are similar to that of other Caucasian populations.

CYP2C9*3 allele has been reported to correlate with increased plasma concentration of fluvastatin active form in healthy volunteers. We analyzed the correlation between the CYP2C9 genotype and cholesterol-lowering effect of fluvastatin in human hypercholesterolemic patients. The study was prospective, without any interventions to standard procedures of hypolipidemic treatment. CYP2C9 genotype was determined by PCR–RFLP assay in 87 patients on concomitant fluvastatin therapy, in 48 patients on monotherapy, and in a control group of 254 healthy volunteers of Czech nationality. Biochemical and clinical data were collected before the initiation of fluvastatin treatment and 12 weeks later. The frequency of CYP2C9 alleles did not differ significantly among groups of patients and volunteers. The most frequently observed allele was CYP2C9*2. Treatment with 80 mg of fluvastatin daily of 48 patients on monotherapy for 12 weeks resulted in mean low-density lipoprotein cholesterol (LDL-C) reduction by 25%, mean serum total cholesterol (TC) reduction by 21%, and mean triglyceride (TG) reduction by 28%. The CYP2C9*1/*3 genotype was associated with a decrease in LDL-C levels (by 40.0% for CYP2C9*1/*3, but only by 22.4% for CYP2C9*1/*1), and with the reduction of TC (by 28.6% in CYP2C9*1/*3 versus 20.2% in CYP2C9*1/*1). In hypercholesterolemic patients, LDL-C serum concentration was decreased more significantly in fluvastatin-treated subjects bearing the CYP2C9*1/*3 genotype compared to CYP2C9*1/*1 genotype. However, due to rare occurrence of some CYP genotypes, it was impossible to report a definitive positive genotype-fluvastatin effect association.