Joyce Soh

🔥Another reason to monitor patient hydroxychloroquine (HCQ) drug levels (#SLE, #lupus, #Sjogrens): medspoke.co/taps/7822 🧬 This study showed that metabolism and resulting whole blood HCQ levels varied widely based on genetic polymorphisms. 🩸This makes a lot of sense. I have been measuring levels on all my patients regularly for 5-6 years. This helps explain why I have some 300# patients who only need 200 mg qd, while I have some 120# patients who require 400 mg qd to reach trough [HCQ] of 1000 - 1200 ng/mL (my recommended target based upon reducing flares, CV events, and retinopathy per studies by M Petri and N Costedoat-Chalumeau). 💊 Also, per Tett SE et al, European Journal of Pharmacology 183(3): 1035, 1990, the absorption of HCQ varies between 25% and 75%. ⚖️ It makes no sense whatsoever to dose HCQ based on body weight! (genetics and variable absorption!) 📢 I was very happy to see Dr. Arnaud ( @lupusreference) recommend following HCQ drug levels in patients in his talk on the last day of ACR Convergence 2023 in San Diego! It is slowly catching on in mainstream rheumatology. PRACTICAL ADVICE: 👉Start with 5 mg/kg/d HCQ 👉6 weeks later, check a trough HCQ whole blood level (6 weeks' time from personal communication with Dr. Costedoat-Chalumeau) 👉 Ensure patient adherence before adjusting dose (in addition to discussing with the patient, I have my assistant call the pharmacy to ensure med was refilled) 👉 Increase or decrease the dose, aiming for 1000 - 1200 ng/mL 👉 Check the level again in 4 weeks and repeat (4 week time from personal communication with Dr. Costedoat-Chalumeau) 👉 Continue checking [HCQ] every time you do lupus labs to check adherence. Remember, poor adherence is a cause of flares and organ damage. @talkmedspoke