Management of nirmatrelvir/ritonavir and tacrolimus interaction in kidney transplant recipients infected by COVID-19: a three-case series

OBJECTIVES

Nirmatrelvir/ritonavir may cause a clinically relevant drug-drug interaction (DDI) with immunosuppressive drugs, such as tacrolimus, which may condition the use of this antiviral in transplant patients. We aimed to describe the management of this interaction.

METHODS

Descriptive study in which renal transplant patients in treatment with nirmatrelvir/ritonavir and tacrolimus were included. They suspended tacrolimus the day before starting the antiviral treatment, and the decision to restart it was made based on their tacrolimus blood levels. Main variables studied to measure this DDI were tacrolimus blood concentration, dose adjustment and serum creatinine.

RESULTS

Three patients were included. During the study, tacrolimus levels elevation did not have repercussion in the serum creatinine, that remained stable in all patients. No patient required hospitalisation or showed signs of rejection.

CONCLUSIONS

Our experience provides further evidence that this interaction should not be a contraindication to treatment with nirmatrelvir/ritonavir, and can be managed with close monitoring of tacrolimus levels.

Combination of a propofol emulsion with alpha-2 adrenergic receptor agonists used for multimodal analgesia or sedation in intensive care units: a physicochemical stability study

OBJECTIVES

To assess the physicochemical stability of the combination of a propofol emulsion with an alpha-2 (α2) adrenergic receptor agonist (α2A; clonidine or dexmedetomidine) under conditions mimicking routine practice in an intensive care unit or in multimodal analgesia procedures.

METHODS

We developed and validated three stability-indicating methods based on high-performance liquid chromatography with ultraviolet (HPLC-UV) detection. Eight different conditions per combination were evaluated in triplicate, with variations in the simulated, bodyweight-adjusted dose level and the drugs' flow rate. The drugs were mixed in clinically relevant concentrations and proportions and then stored unprotected from light, in clear glass vials at room temperature for 96 hours. At each sampling point, we assessed the chemical stability (the HPLC-UV drug level, pH, and osmolality) and physical compatibility (visual aspect, zeta potential (ZP), mean droplet diameter (MDD, Z-average) and polydispersity index (PDI)). We validated our stability findings in positive and negative control experiments.

RESULTS

Over the 96-hour test, the concentrations of propofol, clonidine and dexmedetomidine did not fall below 90% of the initial value, and the pH and osmolality were stable. The visual aspect of the mixed propofol emulsions did not change. The MDD remained below 500 nm (range 165-195 nm). The PDI was always below 0.4; 78.7% of the measurements were below 0.1 and 21.3% were between 0.1 and 0.4. The ZP measurements (-31.3 to -42.9 mV) suggested that the emulsion was stable. The MDD and PDI increased slightly at 96 hours under some conditions, which might indicate early destabilisation of the emulsion. Given that the MDD remained below 500 nm, these emulsions are compatible with intravenous administration.

CONCLUSIONS

Our results demonstrate the chemical and physical compatibility of propofol-α2 agonist mixtures at concentrations and in proportions representative of standard protocols when stored unprotected from light at room temperature for 96 hours.

No effects of nirmatrelvir/ritonavir on darunavir plasma trough concentrations: a case report

COVID-19 may be associated with worst outcomes in people living with HIV compared with HIV-negative patients. Nirmatrelvir/ritonavir can be safely co-administered with all the HIV antiretroviral drugs, without considering dose adjustment. However, no studies have formally investigated the effect of a double booster (ritonavir plus cobicistat) regimen on darunavir concentrations. We presented a case describing the lack of effects of adding nirmatrelvir/ritonavir on darunavir plasma trough concentrations in a patient with HIV already on treatment with a booster-based antiretroviral regimen. We believe this could be a reassuring message for physicians, allowing them to prevent unnecessary denial of COVID-19 treatment or inappropriate discontinuation of co-medications in patients with HIV.

Physical compatibility of lipid emulsions and intravenous medications used in neonatal intensive care settings

OBJECTIVE

The purpose of this study was to investigate the physical compatibility of intravenous lipid emulsions with parenteral medications used in neonatal intensive care.

METHODS

Lipid emulsion and drug solutions were combined 1:1 in glass vials, inspected for physical incompatibility at 0, 1 and 2 hours, and assessed on the basis of lipid droplet size at 0 and 2 hours after mixing. Intravenous fluid controls (Water for Injection, sodium chloride 0.9% w/v, glucose 5% w/v), positive controls (gentamicin, albumin), negative controls (metronidazole, paracetamol, vancomycin) and 21 previously untested drug combinations were evaluated.

RESULTS

No phase separation, change in colour, gas production or other visible anomaly was observed. The between-run mean droplet diameter (MDD) for SMOFlipid20% alone (0.301±0.008 µm) was comparable to the lipid emulsion/intravenous fluid and lipid emulsion/drug solution combinations. In addition to gentamicin and albumin, caffeine citrate (20 mg/mL) was shown to be incompatible with the lipid emulsion. All other lipid:drug combinations were compatible, based on the MDD data.

CONCLUSION

Intravenous lipid emulsions were found to be compatible with 20 parenteral medications, including antimicrobial agents, inotropes, anti-inflammatory drugs and caffeine base, in simulated Y-site conditions. The lipid emulsion was incompatible with caffeine citrate injection.

Y-site simulation compatibility study of 10% calcium salts with various injectable solutions during toxicological resuscitation

PURPOSE

To determine the physical compatibility of 10% calcium chloride and 10% calcium gluconate in combination with injectable solutions, administered in the paediatric and adult intensive care unit setting during toxicological resuscitation involving calcium channel blockers and beta-blockers.

METHODS

Forty-eight combinations were prepared at room temperature, including the following products: calcium chloride, calcium gluconate, insulin, epinephrine, norepinephrine, highly concentrated dextrose solution, sodium chloride, Plasma-Lyte A and Ringer's lactate. A visual evaluation at times 0, 1, 4, 24, 48 and 72 hours and a particle count test with the LS-20 particle counter at times 0, 4, 24 and 72 hours were performed. The admixtures were considered incompatible if there was a precipitate, a colour change, turbidity, viscosity or a gas formation. The stability of calcium salts was also tested in empty IV bags and syringes by the particle count test.

RESULTS

All drug mixtures were found to be compatible by visual evaluation and using the particle counter based on United States Pharmacopoeia chapter 788 (USP<788>) specifications. Calcium salts were compatible with insulin and vasopressors in the tested combinations. The stability of 10% calcium salts in empty IV bags and polypropylene syringes was demonstrated for up to 48 hours at room temperature.

CONCLUSION

All the combinations tested were physically compatible for up to 72 hours at room temperature. Clinical use of calcium salt infusions, at an undiluted concentration, in combination with these injectable solutions in a toxicological resuscitation context is considered clinically acceptable.

A new function in the Stabilis database: physical compatibility and incompatibility of injectable drugs to secure Y-site administration

OBJECTIVES

In intensive care units, the mixing of injectable drugs via Y-site administration is often necessary. However, some mixtures can lead to physical incompatibility or chemical instability. To assist healthcare professionals, several databases such as Stabilis compile compatibility and stability data. The objectives of this study were to update the online database Stabilis by adding physical compatibility data to the website and to characterise the incompatibility data already present in the database by specifying the phenomenon at the origin of the incompatibility and its time of occurrence.

METHODS

Bibliographic sources referenced in Stabilis were evaluated using several criteria. After the evaluation, studies were rejected or the data they contain were added to the database. Data entries contained the following information: name of the two injectable drugs involved in the mixture and their concentration if available, the dilution solvent and the phenomenon at the origin of the incompatibility and its time of occurrence for incompatibility data. Three functions of the website were modified, including the 'Y-site compatibility table' function, which allows creation of customised compatibility tables.

RESULTS

A total of 1184 bibliographic sources were evaluated, 77.3% (n=915) of which were scientific articles, 20.5% (n=243) were Summaries of Product Characteristics and 2.2% (n=26) were communications in a pharmaceutical congress. After evaluation, 28.9% (n=342) of the sources were rejected. From the 71.1% (n=842) sources selected, 8073 (70.2%) compatibility data entries and 3433 incompatibility data entries (29.8%) were made. With the addition of these data, the database contained compatibility and incompatibility data for 431 injectable drugs.

CONCLUSIONS

Since the update, the 'Y-site compatibility table' function has seen its traffic increased by about 66% (∼1500 tables per month compared with ∼2500 tables per month). Stabilis is now more complete to offer significant help to healthcare professionals with their problems of drug stability and compatibility.

A new approach to drug intravenous compatibility research: the case of obstetric parenteral drugs

OBJECTIVES

The product information and literature does not provide confirmation of compatibility for co-administration of all commonly used drug pairs in obstetrics. However, there is a need for co-administration of these drugs over one lumen for this group of patients. Therefore, this study focuses on Y-site compatibility. Since different conditions between clinical and laboratory settings can lead to discrepancies in results, a novel approach for drug intravenous compatibility testing was designed to reflect clinical conditions. The aim was to study the compatibility of nine commonly used drug pairs in obstetrics and to evaluate the clinical value of the designed method.

METHODS

The clinical situation was reflected by using different temperature ranges (20°C and 37°C), actual Y-site flow ratios, clinically relevant drug pairs and an observation time of 120 min. The clinically relevant drugs pairs include atosiban, nicardipine, amoxicillin/clavulanic acid, oxytocin, remifentanil, labetalol and magnesium sulpfate. Drug pairs were visually assessed according to the European Pharmacopoeia (Ph. Eur.) and pH was measured. When incompatibility of a drug pair seemed likely based on literature review or observed abnormalities during visual assessment, subvisual analysis was performed using a particle counter. Y-site compatibility applied for drug pairs when no visual changes occurred or when no additional particles were formed during the observation time.

RESULTS

Eight of the nine combinations showed no visual changes or noticeable changes in pH during the observation time. The amoxicillin/clavulanic-acid-oxytocin combination showed a colour change at 37°C at the actual Y-site flow ratio. However, subvisual particle counting showed no formation of additional particles.

CONCLUSIONS

Y-site compatibility was established for all tested drug pairs. The new clinical approach for analysing Y-site compatibility provides a high certainty of outcomes for clinical practice. In this way, clinical complications and use of several additional intravenous catheters can be avoided.

Burden of enteral supplement interactions with common antimicrobial agents: a single-centre observational analysis

INTRODUCTION

Oral antimicrobials, including ciprofloxacin, levofloxacin and doxycycline, are susceptible to binding with enteral therapies such as calcium and iron therapies. Administered together, the bioavailability of these antimicrobials is expected to be reduced.

METHODS

A retrospective case series of patients receiving oral antimicrobials (ciprofloxacin, levofloxacin and doxycycline) was analysed at a single-centre NHS acute hospital (April 2016-September 2019). Patient demographics, including concurrent enteral therapies, were recorded using medical records. Clinically important interactions were defined as doses administered within 2 hours of antimicrobial therapy.

RESULTS

A total of 4067 prescriptions for the study antimicrobials (ciprofloxacin, n=1905; levofloxacin, n=538; and doxycycline, n=1624) were prescribed for 3584 patients. 1918/3583 (53.5%) of the patients were female, and the median age was 67 years (range 0.5-105.0 years). 810/4067 (19.3%) prescriptions reviewed had an interacting enteral therapy (calcium or iron salt) administered within 2 hours of the study medication.

CONCLUSION

The concomitant administration of enteral calcium and iron with oral antimicrobials is common within the acute care hospital setting. Approximately one in five patients has a clinically important interaction which may impair oral bioavailability and limit treatment efficacy. As antimicrobial stewardship teams strive for increased intravenous-to-oral de-escalation, it is important that optimum dosing administration is followed to optimise patient outcomes.

High concentrated etoposide solutions, additional physical stability data in dextrose 5

OBJECTIVES

According to the manufacturers, the concentration of etoposide solutions should not exceed 0.4 mg/mL due to a risk of precipitation. Stability studies at higher concentrations were conducted and notably demonstrated 28 day stability up to 1.75 mg/mL for etoposide solutions in 5% dextrose (D5W). Nevertheless, colleagues report precipitation even at 0.4 mg/mL in their daily practice. The objective of this work was to reassess the physical stability of highly concentrated etoposide solutions in D5W (1.2 mg/mL), over a large number of preparations and under different manufacturing processes.

METHODS

To study the impact of manufacturing process, etoposide was taken with a spike or a needle and injected in three types of D5W containers (Easyflex, Viaflo and Ecoflac). Forty preparations were made for each container. For half of the preparations, a homogenisation was performed by a syringe rinse. Physical stability was realised by two examiners, with a visual examination searching for the appearance of a precipitate, daily during the first week, then twice a week until day 56.

RESULTS

Hundred and eighteen solutions were clear and colourless. Precipitates were observed for two solutions: one in an Easyflex bag on day 4 and one in an Ecoflac container on day 35.

CONCLUSIONS

The physical stability at 1.2 mg/mL in D5W remains validated. Precipitations are rare and concern less than 2% of preparations. The appearance of a precipitate does not seem to be correlated to the kind of container or manufacturing process. A rinse was performed for these two solutions to assess a mechanical pressure effect more important on the solution, which could lead to a higher risk of precipitations. However, this is not observed in our daily practice, especially at lower concentrated solutions. We only recommend using an administration set with an in-line micro-filter as a precaution in case of precipitations.