Introduction There is a large variation in cannabidiol (CBD) pharmacokinetics and little information on its bioavailability. This study aims to establish the CBD dose‐exposure relationship and to evaluate the effects of dosage forms, food, and doses on CBD absorption. Methods Single‐dose (range: 5–6000 mg) CBD plasma concentration‐time profiles administered as oral solution (OS), oral capsule (OC), or oromucosal spray/drop (OM) from healthy volunteers were extracted from 15 published clinical studies. A dose‐exposure proportionality assessment was performed, and a population‐based meta‐analysis of CBD pharmacokinetics and systemic bioavailability was conducted with a nonlinear mixed‐effects modeling. A three‐compartment model with a Weibull or zero‐order absorption model was used to describe CBD disposition and absorption kinetics. Dosage form, food, and dose were assessed for covariation. Results Oral solution CBD exposures increased less than proportionally with doses of 750 mg or greater, and bioavailability (6.5% at 3000 mg) decreased with increasing dose. The bioavailability of OC (5.6%) and fed‐state OM (6.2%) were similar, whereas it was lower in fasted‐state OM (0.9%). The Weibull absorption model best described OS, OC, and fed‐state OM profiles. The slowest absorption rate was observed in OS, resulting in a time of maximum concentration of 4.75 hours, followed by fed‐state OM (3.13 hrs) and OC (2.1 hrs). The absorption kinetics of fasted‐state OM was best described by a zero‐order absorption for the duration of 1.71 hours. Conclusion The effects of doses, dosage forms, and feeding status on CBD pharmacokinetics were quantified and should be taken into consideration for dose optimization.

Purpose The changes in physiological functions as children grow and organ systems mature result in pharmacokinetic alterations throughout childhood. These alterations in children result in absorption, distribution, metabolism, and excretion of drugs that are different from those seen in the typical adult diseased population. Summary Changes in gastrointestinal motility and gastric pH in neonates and infants affect the absorption rate and bioavailability of drugs. Skin absorption rate and extent can be altered by different skin structures and perfusion in young children. Intramuscular and rectal absorption become less predictable in children due to erratic absorption site perfusion and other factors. Children’s body compositions also differ greatly from that in adults. Water-soluble drugs distribute more extensively in newborns due to larger water content than in older children and adults. Drug elimination and excretion are also affected in pediatric population due to differences in liver and renal function. Immature enzyme development and renal function result in reduced clearance of drugs in young children. There are limited pharmacokinetic data available for many drugs used in children. Conclusion Considering the changes in pharmacokinetics in children can help pharmacists optimize the dosing and monitoring of drugs and do the best they can to help this vulnerable population.

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Background: Opioid rotations from fentanyl to hydromorphone may reduce opioid/sedative exposure in critically ill children. Objective: The primary objective was to determine the conversion percentage from fentanyl to hydromorphone infusions using equianalgesic conversions (0.1 mg fentanyl = 1.5 mg hydromorphone). Secondary objectives included identification of the median time and hydromorphone rate at stabilization (defined as the first 24-hour period no hydromorphone rates changed, 80% of State Behavioral Scale [SBS] scores between 0 and −1, and <3 hydromorphone boluses administered). Additional outcomes included a comparison of opioid/sedative requirements on the day of conversion versus the three 24-hour periods prior to conversion. Methods: This retrospective study included children <18 years old converted from fentanyl to hydromorphone infusions over 6.3 years. Linear mixed models were used to determine if the mean cumulative opioid/sedative dosing differed from the day of conversion versus three 24-hour periods prior to conversion. Results: A total of 36 children were converted to hydromorphone. The median conversion percentage of hydromorphone was 86% of their fentanyl dose (interquartile range [IQR] = 67-100). The median hydromorphone rate at stabilization was 0.08 mg/kg/h (IQR = 0.05-0.1). Eight (22%) were stabilized on their initial hydromorphone rate; 8 (22%) never achieved stabilization. Patients had a significant decrease in opioid dosing on the day of conversion versus the 24-hour period prior to conversion but no changes in sedative dosing following conversion. Conclusion and Relevance: A median 14% fentanyl dose reduction was noted when transitioning to hydromorphone. Further exploration is needed to determine if opioid rotations with hydromorphone can reduce opioid/sedative exposure.