Effects of Grapefruit and Seville Orange Juices on the Pharmacokinetic Properties of Colchicine in Healthy Subjects

Gout and Diet: A Comprehensive Review of Mechanisms and Management

Gout is well known as an inflammatory rheumatic disease presenting with arthritis and abnormal metabolism of uric acid. The recognition of diet-induced systemic metabolic pathways have provided new mechanistic insights and potential interventions on gout progression. However, the dietary recommendations for gouty patients generally focus on food categories, with few simultaneous considerations of nutritional factors and systemic metabolism. It is worthwhile to comprehensively review the mechanistic findings and potential interventions of diet-related nutrients against the development of gout, including purine metabolism, urate deposition, and gouty inflammation. Although piecemeal modifications of various nutrients often provide incomplete dietary recommendations, understanding the role of nutritional factors in gouty development can help patients choose their healthy diet based on personal preference and disease course. The combination of dietary management and medication may potentially achieve enhanced treatment effects, especially for severe patients. Therefore, the role of dietary and nutritional factors in the development of gout is systematically reviewed to propose dietary modification strategies for gout management by: (1) reducing nutritional risk factors against metabolic syndrome; (2) supplementing with beneficial nutrients to affect uric acid metabolism and gouty inflammation; and (3) considering nutritional modification combined with medication supplementation to decrease the frequency of gout flares.

Liquid Chromatography Tandem Mass Spectrometric Analytical Method for Study of Colchicine in Rats Given Low Doses

A selective and sensitive assay was developed for colchicine in rat specimens. Colchicine and its deuterated analog (as internal standard, IS) were extracted from rat specimens (minimal 0.1 mL plasma, whole blood, or urine) using liquid-liquid extraction with n-hexane:dichloromethane:isopropanol. The mobile phase (formic acid: ammonium acetate: methanol) was pumped with uniform flow through an octadecylsilane analytical column. Detection was carried out by electrospray positive ionization in the multiple-reaction monitoring mode. The assay (total run time <3 min) had excellent linearity over a wide (400–800-fold) concentration range. The mean absolute recovery was >96.8%. The intra- and inter-day coefficients of variation were ˂15%, with lower limits of quantitation of 0.5 ng/mL in 0.1 mL of rat plasma. The method also provided the same lower limits of quantitation in urine and whole blood with 0.1 mL volumes, and 0.1 ng/mL using 0.5 mL of rat plasma. The blood-to-plasma ratio was >1. Rats had measurable colchicine blood concentrations for at least 24 h after intravenous doses of 0.1 mg/kg. The method possessed suitable measures of sensitivity and selectivity for detecting colchicine in several specimen types in rats given low doses.

Therapeutic Implications of a Polymethoxylated Flavone, Tangeretin, in the Management of Cancer via Modulation of Different Molecular Pathways

Chemotherapeutics can induce oxidative stress, inflammation, apoptosis, mitochondrial dysfunction, and abnormalities in neurotransmitter metabolism leading to toxicity. Because there have been no therapeutic strategies developed to target inflammation and oxidative stress, there is a continuing need for new and improved therapy. As a result, there has been increasing interest in complementary and alternative medicine with anticancer potential. Studies have shown that the antioxidant activities and anti-inflammatory effects of citrus fruits are promising natural phytochemicals in the development of new anticancer agents. Tangeretin is a naturally polymethoxylated flavone compound extracted from the citrus peel that has shown significant intestinal absorption and adequate bioavailability, with the added benefit of promoting longevity. In addition, tangeretin is known to exhibit considerable selective toxicity to many types of cancer cell proliferation such as ovarian, brain, blood, and skin cancer. Evidence indicates that tangeretin acts through several mechanisms including growth inhibition, induction of apoptosis, autophagy, antiangiogenesis, and estrogenic-like effects. Furthermore, tangeretin works through mitigating levels of inflammatory mediators in the immune system. Using tangeretin in combination with clinically applied anticancer drugs could be a good strategy for increasing the efficiency of these agents and protecting noncancerous cells from damage caused by chemotherapy. The purpose of this review is to highlight the protective effects of a novel natural product, tangeretin against chemotherapeutic-induced toxicity. The development of chemoprevention strategies can lead to significant health care improvement in cancer survivors. Thus, study outcomes may attract more investigators to conduct tangeretin-related research and find out potentially significant impacts on health care of cancer patients and decreased health problems associated with chemotherapeutics-induced toxicity.

Lithium + Colchicine: A Potential Strategy to Reduce Pro-inflammatory Effects of Lithium Treatment

PURPOSE

Rosenblat and McIntyre (Acta Psychiatr Scand. 2015;132: 180-191) propose that immune disorders are important mediators between bipolar disorders and medical comorbidities. Rosenblat et al (Bipolar Disord. 2016;18:89-101) present a meta-analysis showing that adjunctive anti-inflammatory agents could evoke moderate antidepressant responses in bipolar disorders. We propose using the anti-inflammatory drug colchicine to improve the long-term safety and efficacy of lithium treatment for bipolar disorders.

METHODS

This report is based on searches of the PubMed and Web of Science databases.

RESULTS

Bipolar disorders are associated with significant medical comorbidities such as hypertension, overweight/obesity, diabetes mellitus, metabolic syndrome, and arteriosclerosis, accompanied by enhanced release of pro-inflammatory markers during changes in mood state. During lithium therapy, granulocyte-colony stimulating factor, CD34+ hematopoietic stem/progenitor cells, and neutrophil elastase enter the circulation with activated neutrophils to promote the extravascular migration of activated neutrophils and enhance tissue inflammation. Concurrent treatment with lithium and low-dose colchicine could facilitate the responsiveness of bipolar patients to lithium by reducing leukocyte tissue emigration, the release of neutrophil elastase, and the release of leukocyte pro-inflammatory cytokines such as IL-1β that are regulated by the NLRP3 inflammasome assembly complex.

CONCLUSIONS

Concurrent therapy with lithium and low-dose colchicine could reduce complications involving leukocyte-mediated inflammatory states in bipolar patients and promote patient acceptance and responsiveness to lithium therapy.

Effects of Lemon and Seville Orange Juices on the Pharmacokinetic Properties of Sildenafil in Healthy Subjects

PURPOSE

Several severe drug interactions have been reported when sildenafil, a potent drug for the treatment of erectile dysfunction, is co-administered with drugs or herbal remedies that inhibit cytochrome P450 (CYP) 3A4. This study evaluates the effects of two citrus fruit juices, lemon and Seville orange, on the pharmacokinetics of sildenafil in male healthy subjects following a single oral dose.

METHODS

We conducted an open-label, three-way crossover study in nine healthy male volunteers. Participants received a single oral dose of sildenafil (50 mg) after pretreatment with 250 mL of either water (control), undiluted lemon juice, or Seville orange juice for 3 consecutive days. All subjects were monitored for adverse effects during the study period. Plasma samples were collected for 12 h after dosing and analyzed for sildenafil concentration.

RESULTS

Compared with pretreatment with water, Seville orange juice significantly increased the area under the plasma concentration-time curve from time zero to infinity and the peak plasma concentration of sildenafil by 44 % (90 % confidence interval [CI] 30-60) and 18 % (90 % CI 108-129), respectively, without affecting the time to reach peak plasma concentration. Additionally, Seville orange juice significantly reduced the apparent oral clearance of sildenafil by 30 % (90 % CI 63-75) without affecting its elimination half-life. In contrast, lemon juice did not cause any significant alterations in the pharmacokinetics of sildenafil. There was no significant treatment-related adverse effects reported during the study.

CONCLUSIONS

Although it is considered as a moderate CYP3A4 inhibitor, Seville orange only caused a mild increase in exposure to sildenafil after a single oral dose, without manifestation of any adverse effects. The enhanced bioavailability of sildenafil by Seville orange may be attributed to inhibition of its intestinal first-pass effect (CYP3A4 and or p-glycoprotein). Lemon juice, in contrast, had no effects on the pharmacokinetics of sildenafil.

Pharmacotherapeutic considerations for using colchicine to treat idiopathic pericarditis in the USA

The clinical significance of colchicine in the treatment of acute idiopathic (viral) pericarditis (IP) was only elucidated less than a decade ago. Multiple trials have shown the benefit of colchicine in decreasing the rate of recurrence, primarily in the European population. However, the colchicine formulation used in these trials is not available in Western countries such as the USA. In the USA, two formulations are available: the 0.6 mg capsule and the 0.6 mg tablet. As a result, higher doses than administered in the European trials must be utilized to treat IP. However, the use of these dosage forms has never been studied in the treatment of IP. Pharmacokinetic and pharmacodynamic knowledge of colchicine germane to clinicians such as drug disposition and drug-drug or drug-disease interactions have not been extensively reviewed in recent years. Furthermore, the safety of colchicine in the treatment of IP has not been extensively studied, and literature regarding adverse drug events originates from data in patients treated for familial Mediterranean fever and gout. This review will help the clinician understand pharmacotherapeutic considerations and thereby optimize therapy and ensure patient safety when using colchicine to treat IP.

An evidence-based systematic review of bitter orange (Citrus aurantium) by the Natural Standard Research Collaboration

An evidence-based systematic review of bitter orange (Citrus aurantium) by the Natural Standard Research Collaboration consolidates the safety and efficacy data available in the scientific literature using a validated, reproducible grading rationale. This article includes written and statistical analysis of clinical trials, plus a compilation of expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.