The edition · Clinical Pharmacology
In liver dysfunction, creatinine flatters the kidneys and vancomycin exposure drifts — measure early
Population estimates of vancomycin exposure went astray more often in hepatic dysfunction; orforglipron's interaction profile is mapped; a hydroxychloroquine metabolite tracks with lupus control; a case suggests lenacapavir held its levels alongside primidone; and compounded GLP-1 syringes are recalled.
The edition in brief
In 157 adults on vancomycin, hepatic dysfunction with albumin below 2 g/dL more than doubled the odds that the Bayesian, trough-informed AUC differed from the population-model estimate by 30% or more (aOR 2.26), with higher exposure; creatinine-based clearance overstates kidney function when creatinine production is low, so early level-guided dosing is advised. Six phase 1 studies show orforglipron exposure rises with clarithromycin and ciclosporin and falls with carbamazepine; it had no meaningful effect on midazolam, digoxin or atorvastatin and a weak effect on rosuvastatin. In 102 Japanese patients with lupus, the metabolite desethylhydroxychloroquine, governed by CYP2D6 genotype, was associated with low disease activity while parent hydroxychloroquine levels were not; discrimination was modest. In one man on primidone, lenacapavir levels stayed above four times the protein-adjusted effective concentration with undetectable viral load. The FDA lists Class II recalls of compounded tirzepatide and semaglutide syringes for lack of sterility assurance.
Orforglipron's interactions: CYP3A4 and OATP1B inhibitors raise it, inducers lower it
When a patient on orforglipron starts a strong CYP3A4 or OATP1B inhibitor or an inducer, expect its levels to move and monitor tolerance and glucose.
In lupus, the hydroxychloroquine metabolite — not the parent drug — tracked with disease control
Hydroxychloroquine's metabolite, governed by CYP2D6, tracked with lupus control; treat it as a research marker, not a test to order.
Lenacapavir stayed in range alongside low-dose primidone in one patient
Lenacapavir with primidone remains a combination to avoid, but level monitoring made it workable in one patient with no alternative.
FDA lists Class II recalls of compounded tirzepatide and semaglutide syringes
Find out whether patients' incretin injections are compounded; compounded syringes from one US firm are being recalled over sterility.
Enzyme induction takes days to build and weeks to fade
Plan for both the start and the end of an inducer: levels fall over one to two weeks, and rebound as it wears off.
In hepatic dysfunction, population models misjudge vancomycin exposure — measure levels early
In hepatic dysfunction with very low albumin, consider measuring vancomycin levels early; population-model estimates were often off by 30% or more.
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