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General pharmacology
Published in Fazal-I-Akbar Danish, Ahmed Ehsan Rabbani, Pharmacology in 7 Days for Medical Students, 2018
Fazal-I-Akbar Danish, Ahmed Ehsan Rabbani
In clinical practice, the phenomenon of enzyme induction is sometimes exploited for the benefit of the patient. For example, premature jaundiced babies are prescribed phenobarbitone – an enzyme inducer. This drug, by inducing hepatic glucuronyltransferase, increases bilirubin conjugation in the hepatocytes with subsequent excretion in the bile. The risk of kernicterus is thus reduced.
Contraception
Published in Elaine Cooper, John Guillebaud, Morgan Williams, Sexuality and Disability, 2017
Elaine Cooper, John Guillebaud, Morgan Williams
Some centres measure the oestradiol level and, if this is less than 100 pg/mol/litre, advise either a change of method or addition of oestrogen. If this is given as Premarin, it will have the least possible effect on thrombotic risk. As with all other hormonal methods, there is at least a theoretical risk of reduction of efficacy if an enzyme-inducer is also being taken (e.g. some anticonvulsants). The time interval of the injection should be reduced to 10 weeks. Although no one likes injections, most people can tolerate them but some are ‘terrified’ of needles. An advantage for some women with spina bifida or spinal injury is that they cannot feel the needle.
Important adverse drug reactions and drug:drug interactions
Published in Hugh McGavock, Dennis Johnston, Treating Common Diseases, 2017
Hugh McGavock, Dennis Johnston
Several drugs are broken down in the liver, where enzymes can be altered in two important ways. The enzymes can become more active, so that other drugs are broken down more rapidly and their effect is diminished (enzyme induction). Rifampicin, a drug that is widely used to treat tuberculosis, and drugs used to treat epilepsy are good examples of enzyme inducers. Warfarin is the most important drug to be affected in this way. Enzyme inducers will decrease the effect of warfarin so that the patient’s blood is more likely to clot. Doctors will increase the dose of warfarin to overcome the reduced effect. The patient will then be at no increased risk unless the enzyme inducer is stopped. If this occurs, the patient is now more likely to bleed. Drugs that suppress enzyme activity are even more dangerous, because their effect is rapid. Cimetidine, an ulcer-healing drug and enzyme inhibitor, if given to a patient on warfarin will prevent the breakdown of warfarin and increase the risk of bleeding over a very short time period.
Chemopreventive role of arabinogalactan against experimentally induced pulmonary carcinogenesis: a study in relation to its initiation phase
Published in Drug and Chemical Toxicology, 2021
Ashwani Koul, Shaffy Garg, Vandana Mohan
Among the detoxifying mechanisms of xenobiotic metabolism, a key role is played by GST, a component of phase II enzymes that functions primarily in conjugating ‘functionalized P450 metabolite’ with endogenous ligands (GSH) rendering them suitable for elimination from the body (Singh et al.2006). In present study, the activities of the phase II enzyme were significantly decreased in B(a)P-induced animals, which denote that tissue were more susceptible to carcinogenic effect of B(a)P. There is strong evidence to suggest a relationship between the depletion of GST and an increase in cancer susceptibility (Hosgood et al.2007). The observed concomitant increase in GST activity upon AG administration in B(a)P treated animals depicts the role of AG in increasing the ability of the cells to detoxify activated metabolic compounds of B(a)P by upregulating the activity of GST. An earlier investigation also supports our observation which showed that supplementation of water-soluble polysaccharide from Antrodia cinnamomea significantly elevated the GST activity in submerged cultured liver cells (Tsai et al.2007). It is evident from the present findings that AG acts as bifunctional enzyme inducer as it induces both phase I and II enzyme systems at different time intervals during the initiation of carcinogenesis. This reinforces the balance of xenobiotic metabolism towards detoxification and therefore, might be attributed to playing a major role in cytoprotection and chemoprevention.
Eslicarbazepine acetate in epilepsies with focal and secondary generalised seizures: systematic review of current evidence
Published in Expert Review of Clinical Pharmacology, 2018
Laurent M. Willems, Johann Philipp Zöllner, Esther Paule, Susanne Schubert-Bast, Felix Rosenow, Adam Strzelczyk
Overall ESL is well tolerated, its side effects, including dizziness and somnolence, are typical for sodium channel blockers, while hyponatremia is typical for all dibenzazepin AEDs. The extent of hyponatremia depends on the study population examined and might be lowest in patients who did not experience hyponatremia on CBZ and OXC. Combination of different dibenzazepines or other sodium channel blockers should be avoided to improve safety and minimize the rate of AE. Use of drugs that predispose to hyponatremia such as diuretics (e.g. hydrochlorthiazide, furosemide, or torsemide), serotonine reuptake inhibitors (e.g. escitalopram or paroxetine), or serotonin-norepinephrine reuptake inhibitors like venlafaxine should be minimized. In contrast to newer AEDs, such as levetiracetam, perampanel [92], and brivaracetam [93], ESL is less likely to cause psychobehavioral side effects. Although ESL is a weaker enzyme inducer than CBZ and OXC, a number of interactions have to be considered in clinical practice, especially the effect of oral contraceptives might be limited. As of yet, long-term experience is still needed to make severe late-occurring adverse events unlikely and to obtain data regarding its use in pregnancy.
An overview of alogliptin + pioglitazone for the treatment of type 2 diabetes
Published in Expert Opinion on Pharmacotherapy, 2022
Brian Tomlinson, Paul Chan, Christopher Wai Kei Lam
Gemfibrozil, a strong CYP2C8 inhibitor, increased the AUC of pioglitazone 3.2-fold (range, 2.3-fold to 6.5-fold) and prolonged its elimination t1/2 from 8.3 to 22.7 hours, whereas itraconazole, a strong CYP3A4 inhibitor, had no significant effect on the pharmacokinetics of pioglitazone [75]. The dose of pioglitazone should be limited to 15 mg when used in combination with gemfibrozil. Rifampicin, an enzyme inducer, caused a substantial decrease in the plasma concentration of pioglitazone [76]. Polymorphism in CYP2C8 also affect pioglitazone pharmacokinetics, but it is not known if they influence glycemic efficacy [77].