China
Africa
Explore chapters and articles related to this topic
The Precision Medicine Approach in Oncology
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
Various SNP-screening projects underway have the goal of associating gene variations with specific diseases such as asthma, diabetes, arteriosclerosis, psychiatric disorders, and a predisposition to cancer. The other important application of SNP analysis is the prediction of drug safety and efficacy for individual patients. One of the first applications to be explored was evaluation of the status of drug-metabolizing enzymes such as cytochrome P450 to attempt to predict exposure and dose. Warfarin, still the most widely used anticoagulant drug worldwide, is often quoted as proof-of-concept for this approach in Precision Medicine. Although the activity of warfarin is closely related to its concentration in blood, patients’ responses to the drug are highly variable. Therefore, they must be monitored closely during the first few days of treatment so that the dose can be optimized according to the International Normalized Ratio (INR) for prothrombin. In fact, the blood concentration of warfarin is a balance between intake, metabolism, and elimination. It is metabolized in the liver by the enzyme CYP2C9, whose activity varies genetically in 35% of the white population. Therefore, testing for CYP2C9 genetic variants can provide clinical support for dose adjustment and can reduce the risk of life-threatening bleeding particularly when initiating patients on warfarin.
Paediatric clinical pharmacology
Published in Evelyne Jacqz-Aigrain, Imti Choonara, Paediatric Clinical Pharmacology, 2021
Evelyne Jacqz-Aigrain, Imti Choonara
CYP2C9. The gene of CYP2C9 has at least three important allelic variants denoted as CYP2C9*1 (which corresponds to the reference gene), CYP2C9*2, and CYP2C9*3. CYP2C9 is responsible for the oxidative metabolism of widely used drugs, such as anticoagulants (warfarin), non-steroidal antiinflammatory drugs (indomethacin, diclofenac, celecoxib etc.), phenytoin, tolbutamide, angiotensin receptor antagonists, etc. Therefore, polymorphic metabolism catalysed by this enzyme may have clinical implications, predominantly in the treatment of cardiovascular disease and epilepsy.
Herbs with Antidepressant Effects
Published in Scott Mendelson, Herbal Treatment of Major Depression, 2019
The Botanical Safety Handbook notes no known interactions with drugs. One study demonstrated that various extracts of vinegar baked root of Bupleurum chinense, a common potentizing method of preparing the herb in TCM, had negligible effects on activities of CYP1A2 or CYP3A4 enzymes. However, potential for interference of metabolism of CYP2C9 substrates was noted.18
An updated evaluation of avatrombopag for the treatment of chronic immune thrombocytopenia
Published in Expert Review of Clinical Immunology, 2022
Andrew B. Song, Hanny Al‐Samkari
Avatrombopag metabolism is primarily hepatic via CYP3A and CYP2C9. It is mostly metabolized into 4-OH-avatrombopag. Preclinical studies co-administered fluconazole (moderate inhibitor of both CYP3A and CYP2C9), itraconazole (strong CYP3A inhibitor), and rifampin (strong inducer of CYP3A and moderate inducer of CYP2C9) with avatrombopag [28]. Fluconazole lead to clinically significant increases in AUC, half-life, and increase in maximum platelet count while itraconazole had a mild increase on both pharmacokinetics and pharmacodynamics compared to fluconazole. Rifampin on the other hand caused a decreased AUC and half-life without impact on maximum platelet count. These results suggested that CYP2C9 metabolism is more significant in clearance than CYP3A. Dose adjustments may be recommended for patients taking medications known to modulate CYP3A and CYP2C9 metabolism. Although genetic variation in CYP2C9 has been associated with variations in exposure to avatrombopag, this is not thought to be clinically significant.
Evaluation of the effect of Bovis Calculus Artifactus on eight rat liver cytochrome P450 isozymes using LC-MS/MS and cocktail approach
Published in Xenobiotica, 2021
Yun-Jing Zhang, Wen-Li Zhou, Fei Yu, Qian Wang, Can Peng, Jia-Yi Kan
According to our results, BCA could inhibit the CYP2C6 and CYP2D1 activity at medium and high dosage and could inhibit the CYP2C11 activity at high dosage. As the second most abundant CYPs (∼20%), the CYP2C subfamily can catalyse 16–20% of prescribe drugs. CYP2C9 constitutes ∼20% of hepatic total CYP content. About 15% of clinical drugs (>100 drugs) are metabolized by this enzyme, including those that have a small therapeutic range (Shimada et al. 1994; Miners and Birkett 1998). Therefore, an increase or decrease in the activity of CYP2C9 will greatly affect the therapeutic effect of many drugs. Although CYP2D6 only accounts for 1.3–4.3% of total hepatic CYPs content, it contributes to approximately 20% of clinical trials (Di et al. 2009). It suggested that BCA was used in combination with other drugs metabolized by the CYP2C9, 2C19 or CYP2D6, the potential BCA-drug interactions should be carefully noted to reduce some adverse reactions.
4-O-galloylalbiflorin inhibits the activity of CYP3A, 2C9, and 2D in human liver microsomes
Published in Xenobiotica, 2021
Yu Sun, Mengya He, Yanling Sun, Jianhong Wei
Similarly, the inhibition of CYP2C9 and 2 D by 4-O-galloylalbiflorin was also found to be concentration-dependent with various IC50 values. On the contrary, the inhibition of CYP2C9 and 2 D by 4-O-galloylalbiflorin was competitive. The potential causes might be the similar chemical structure or similar functional groups between 4-O-galloylalbiflorin and the substrates of CYP2C9 and 2D6, such as aromatic groups and other binding groups (Ren et al.2009). In previous studies, CYP2C9 and 2 D were also demonstrated to mediate drug-drug interaction (Bahar et al.2017). For instance, the co-administration between capecitabine and celecoxib could prolong the system exposure of capecitabine due to the competition for CYP2C9 (Ramirez et al.2019). Therefore, except for the substrates of CYP3A, it also needs to pay special attention to the drugs metabolized by CYP2C9 and 2 D in the co-administrated prescription with 4-O-galloylalbiflorin in the clinic.