The edition · Clinical Pharmacology
Measure voriconazole and posaconazole levels routinely; the evidence for other antifungals is thinner
A review sets out where antifungal drug monitoring earns its place. Also: inflammation raises exposure to some CYP3A4 drugs, a compounded tirzepatide recall, antiretrovirals in pregnancy, and breastfeeding on medicines.
The edition in brief
A Therapeutic Drug Monitoring review concludes that routine trough monitoring is well supported for voriconazole and posaconazole, may help for isavuconazole in critically ill, paediatric, obese and extracorporeal patients, and is not currently recommended for echinocandins or amphotericin B. A Clinical Pharmacology & Therapeutics review of 20 recently approved small-molecule drugs for chronic inflammatory diseases found five had more than 25% higher exposure in patients than in healthy volunteers, all metabolised mainly by CYP3A4 or CYP2C19, consistent with inflammation suppressing these enzymes. The FDA lists a Class II recall of compounded tirzepatide syringes from one US pharmacy over sterility assurance. A review proposes a framework for judging whether antiretroviral exposure remains effective in pregnancy despite interactions. Five years of breastfeeding queries to the Lyon pharmacovigilance centre (2,473 requests) ended in advice supporting breastfeeding in 87%. The pearl covers levothyroxine absorption.
Chronic inflammation can raise exposure to CYP3A4- and CYP2C19-metabolised drugs
In active inflammatory disease, anticipate higher exposure to CYP3A4 and CYP2C19 substrates, and re-check levels when inflammation settles.
Compounded tirzepatide syringes recalled over sterility assurance
Ask where patients obtain tirzepatide and semaglutide, and steer them away from compounded supplies where licensed product is available.
Judging antiretroviral exposure in pregnancy: proportional change is not enough
When an interaction lowers antiretroviral levels in pregnancy, judge it against the drug's effective target and margin, and monitor viral load.
Most breastfeeding medicine queries ended in support for breastfeeding
Most medicines can be used while breastfeeding; check a lactation resource before advising a mother to stop.
Getting levothyroxine absorbed
When TSH rises on a stable levothyroxine dose, look for a new binding drug or timing change before increasing the dose.
Antifungal drug monitoring: routine for voriconazole and posaconazole
Monitor voriconazole and posaconazole levels routinely, and consider isavuconazole levels in high-risk patients.
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