The Impact of CYP1A2 and CYP2E1 Genes Polymorphism on Theophylline Response

Theophylline use-a conundrum in modern medicine: a case report

Background

The theophylline toxidrome presents with multisystemic involvement that includes cardiovascular, neurologic, metabolic, musculoskeletal, and gastrointestinal manifestations. Considering such a varied spectrum of presentations, it is often difficult to ascertain the diagnosis of this particular toxidrome. Review of home medications is an important step when working with a patient presenting as a toxidrome.

Case Description

The case report is about a 69-year-old female patient who was brought to the emergency room in status epilepticus and atrial fibrillation with rapid ventricular response. She had a prolonged state of drowsiness following an initial antiepileptic therapy and a toxicologic screen positive for toxic levels of theophylline at 59.7 mcg/mL. Emergent dialysis was performed leading to improvement of her overall clinical status. We suspect the patient had built up toxic levels of theophylline due to evolving drug interactions after she discontinued many of her routine home medications following her husband's death.

Conclusions

Theophylline is a methylxanthine derivative medication that is used sparingly in the treatment of airway diseases. It has become less favorable over the years due to its narrow therapeutic index and potential for development of toxicity. Monitoring serum drug levels and adjusting the dose frequently to maintain a therapeutic range is essential to prevent toxicity related to theophylline. There is emerging evidence that the drug might have anti-inflammatory properties to aid in treating many chronic airway disorders and pharmacovigilance is necessary for its continued use.

Contribution of CYP19A1, CYP1A1, and CYP1A2 polymorphisms in coronary heart disease risk among the Chinese Han population

The previous study has pointed to that endogenous CYP metabolites play an important role in the pathogenesis of coronary heart disease (CHD). The study aimed to identify the association of CYP19A1, CYP1A1, and CYP1A2 polymorphisms with CHD susceptibility in a Chinese Han population. A total of 960 genetically unrelated participants consist of 480 CHD patients and 480 healthy controls were enrolled. Nine SNPs in CYP19A1, CYP1A1, and CYP1A2 were randomly selected and genotyped using the Agena MassARRAY platform. Logistic regression analysis was used for the relationship between selected SNPs and CHD susceptibility by calculating odds ratios (OR) with 95% confidence intervals (CI) adjusted for age and gender. The distribution of clinical characteristics in different genotypes was evaluated by one-way analysis of variance (ANOVA). CYP1A2 rs2470890 TT genotype had a higher CHD risk compared with CC genotype (OR = 3.06, p = 0.032) or CC-CT genotype (OR = 3.04, p = 0.033). Moreover, the contribution of CYP19A1 and CYP1A2 polymorphisms to CHD susceptibility was associated with age, gender, and clinical phenotypes (course of the disease and Gensini score). Besides, CYP1A2 rs762551 was related to serum levels of red blood cell, triglyceride, total cholesterol, and low-density lipoprotein cholesterol (LDL-C, p < 0.05). Our findings provided scientific evidence about CYP19A1, CYP1A1, and CYP1A2 polymorphisms on CHD incidence.

Cannabinoid Interactions with Cytochrome P450 Drug Metabolism: a Full-Spectrum Characterization

Medicinal cannabis use has increased exponentially with widespread legalization around the world. Cannabis-based products are being used for numerous health conditions, often in conjunction with prescribed medications. The risk of clinically significant drug-drug interactions (DDIs) increases in this setting of polypharmacy, prompting concern among health care providers. Serious adverse events can result from DDIs, specifically those affecting CYP-mediated drug metabolism. Both cannabidiol (CBD) and Δ⁹-tetrahydrocannabinol (Δ⁹-THC), major constituents of cannabis, potently inhibit CYPs. Cannabis-based products contain an array of cannabinoids, many of which have limited data available regarding potential DDIs. This study assessed the inhibitory potential of 12 cannabinoids against CYP-mediated drug metabolism to predict the likelihood of clinically significant DDIs between cannabis-based therapies and conventional medications. Supersomes™ were used to screen the inhibitory potential of cannabinoids in vitro. Twelve cannabinoids were evaluated at the predominant drug-metabolizing isoforms: CYP3A4, CYP2D6, CYP2C9, CYP1A2, CYP2B6, and CYP2C19. The cannabinoids exhibited varied effects and potencies across the CYP isoforms. CYP2C9-mediated metabolism was inhibited by nearly all the cannabinoids with estimated K_i values of 0.2-3.2 μM. Most of the cannabinoids inhibited CYP2C19, whereas CYP2D6, CYP3A4, and CYP2B6 were either not affected or only partially inhibited by the cannabinoids. Effects of the cannabinoids on CYP2D6, CYP1A2, CYP2B6, and CYP3A4 metabolism were limited so in vivo DDIs mediated by these isoforms would not be predicted. CYP2C9-mediated metabolism was inhibited by cannabinoids at clinically relevant concentrations. In vivo DDI studies may be justified for CYP2C9 substrates with a narrow therapeutic index.

Increased DNA damage is not associated to polymorphisms in OGGI DNA repair gene, CYP2E1 detoxification gene, and biochemical and hematological findings in soybeans farmers from Central Brazil

Our study evaluated 163 individuals, being 74 soybean farmers, occupationally exposed to pesticides, and 89 individuals from Goias municipalities, Central Brazil, with similar conditions to the exposed group, comprising the control group. Of the 74 soybean farmers, 43 exposed directly to pesticides and 31 exposed indirectly. The exposed group consisted of individuals aged 19 to 63 years, 21 women and 53 men, and the control group had ages ranging from 18 to 64 years, being 36 women and 53 men. 18.9% of the exposed group were poisoned by pesticides, and the most common symptoms were headache and gastrointestinal problems. The genotype frequencies of the rs2031920 (T>C) polymorphism in the CYP2E1 gene present significant differences between the exposed and control groups (p = 0.02), showing that 24.3% of the exposed group were heterozygotes against 6.7% in the control group. For the OGG1 gene, two SNPs, rs1052133 (G>C) and rs293795 (T>C), were evaluated and the genotype frequencies were not statistically different between the exposed and control groups. The DNA damage was distinct (p < 0.05) in the three analyzed comet parameters (tail length, Olive tail moment, %DNA) between groups. However, there was no influence of age and alcohol consumption between the groups associated with the polymorphisms in the CYP2E1 and OGG1 genes and DNA damage. We also did not find altered hematological and biochemical parameters in the exposed group. Thus, this pioneering study at Goias State carried out an overview of the health of soybean farmers. We evaluated classic laboratory exams, associated with exposure markers (comet assay) and susceptibility markers (genetic polymorphisms), emphasizing the need to expand the Brazilian health assessment protocol. We found, in soybean farmers, increased DNA damage and a higher number of heterozygotes in CYP2E1 gene, compared with the control group, despite the lack of association with age, educational level, smoking, drinking habits, and genetic polymorphisms.

The effect of CYP1A2 gene polymorphism on the metabolism of theophylline

This aim of the study was to investigate the effect of CYP1A2 gene polymorphism on the metabolism of theophylline in minority and Han nationality. A total of 50 cases of Han (Han group) and 50 minority nationalities (ethnic groups) treated with theophylline were selected for the study. The genotype and allele frequencies of the two groups of CYP1A2 gene, G-3113A and G-3860A, were compared to determine the rate of theophylline clearance. The results showed that there was no significant difference in the concentration of the homeostasis and the rate of the theophylline removal rate (P>0.05). There was no significant difference in the genotype and allele frequencies of the CYP1A2 gene, G-3113A and G-3860A apolymorphic site. This study employed a logarithm to determine theophylline clearance in order to correlate it with the normal distribution. The results showed that the theophylline clearance of the two groups of CYP1A2 G-3113A gene loci A allele carriers (AA+GA genotype) was significantly lower than that of the G allele carriers (GG genotype), and a significant difference between the groups was identified (P<0.05). There was no significant difference in the theophylline clearance rates in the two groups for the CYP1A2 gene, G-3860A apolymorphic site (P>0.05). Compared to the GG genotype of the CYP1A2 gene, the G-3113A site AA and GA genotype patients had a low clearance rate in the theophylline, whereas there was no correlation between teh genotypes of the CYP1A2 gene, G-3860A and the rate of theophylline clearance.