Pattern of Retinopathy: Although the locus of toxic damage is parafoveal in many eyes, Asian patients often show an extramacular pattern of damage. Dose: We recommend a maximum daily HCQ use of 5.0 mg/kg real weight, which correlates better with risk than ideal weight. Asians and plaquenil toxicity Can you take plaquenil as needed Shortness of breath related to plaquenil Plaquenil liver toxicity Cytochrome P450 CYP enzymes play major roles in drug metabolism. Certain single‐nucleotide polymorphisms SNPs in CYP genes may have a large impact on CYP enzyme activity. HCQ is metabolized to N‐desethyl HCQ DHCQ in the liver through the N‐desethylation pathway 10, 11. CYP2C19 and CYP3A4 are the major players in the metabolism of benzodiazepines that undergo phase I metabolism figure 1. Phase I metabolism tends to be reduced in the elderly, along with polypharmacy, predisposing elderly patients to CYP450 related interactions. However, phase II metabolism remains relatively preserved in the elderly. Cytochrome P450 CYP is a hemeprotein that plays a key role in the metabolism of drugs and other xenobiotics Estabrook, 2003. Understanding the CYP system is essential for advanced practitioners APs, as the consequences of drug-drug interactions can be profound. Risk of Toxicity: The risk of toxicity is dependent on daily dose and duration of use. There are no similar demographic data for CQ, but dose comparisons in older literature suggest using 2.3 mg/kg real weight. Hydroxychloroquine metabolism cyp Non-responsive Pain Patients with CYP-2D6 Defect Page 4, Benzodiazepine Metabolism and Pharmacokinetics. Dandelion root and plaquenil Metabolism/Elimination Hydroxychloroquine is metabolized by dealkylation in the liver, primarily by CYP2C8 and CYP3A4 enzymes. The 3 major metabolites of hydroxychloroquine—desethylchloroquine, desethylhydroxychloroquine, and bisdesethylchloroquine—are pharmacologically active and have longer elimination half-lives than the half-life of the parent compound. 7,13 Hydroxychloroquine Information for Providers AIDSinfo. Basic Review of the Cytochrome P450 System. Hydroxychloroquine - Wikipedia. A Table of Substrates, Inhibitors and Inducers. Most chemical inhibitors are not specific for an individual CYP enzyme. The selectivity and potency of inhibitors should be verified in the same. Hydroxychloroquine has also has been found to be taken up into the acidic food vacuoles of the parasite in the erythrocyte. This increases the pH of the acid vesicles, interfering with vesicle functions and possibly inhibiting phospholipid metabolism. The cytochrome P450 2D6 CYP2D6 enzyme is predominantly involved approximately 70-80% in the hepatic metabolism of metoprolol. 1, 2 Since the first description of a CYP2D6 sparteine-debrisoquin polymorphism in the mid-1970’s, substantial genetic heterogeneity has been reported with close to 100 different polymorphisms identified.