Monitoring tacrolimus toxicity following Paxlovid administration in a liver transplant patient.

Maintaining therapeutic plasma tacrolimus concentrations is essential for mitigating potential solid organ transplant rejection and preventing toxic adverse side effects. While patients can benefit greatly from tacrolimus therapy, co-administration of drugs such as Paxlovid (nirmatrelvir/ritonavir) place patients at serious risk for drug interactions and harm. Here we present a case of tacrolimus toxicity following Paxlovid administration in a liver transplant patient. Therapeutic drug monitoring was further complicated by a limited upper reportable threshold for tacrolimus testing and highlights the value of validating a higher limit to the clinical reportable range to improve tacrolimus monitoring and meet clinical needs in the setting of drug toxicity.

Common and Uncommon Causes of Ventriculoperitoneal Shunt Malfunction Diagnosed on Plain Radiographs.

Thousands of patients with hydrocephalus are treated successfully with ventriculoperitoneal shunts. Ventriculoperitoneal shunts are known to have high malfunction rates, most of which are owing to mechanical causes. When shunt malfunction is suspected, shunt series are often performed to evaluate the mechanical causes of malfunction. These initial radiographs have proven critical in guiding subsequent management. This article is designed to review the various causes of shunt malfunction that can be diagnosed with radiographs.