A UPLC-MS/MS Method for Plasma Biological Monitoring of Nirmatrelvir and Ritonavir in the Context of SARS-CoV-2 Infection and Application to a Case.

Nirmatrelvir/ritonavir association has been authorized for conditional use in the treatment of COVID-19, especially in solid-organ transplant recipients who did not respond to vaccine and are still at high risk of severe disease. This combination remains at risk of drug interactions with immunosuppressants, so monitoring drug levels seems necessary. After a simple protein precipitation of plasma sample, analytes were analyzed using an ultrahigh performance liquid chromatography system coupled with tandem mass spectrometry in a positive ionization mode. Validation procedures were based on the guidelines on bioanalytical methods issued by the European Medicine Agency. The analysis time was 4 min per run. The calibration curves were linear over the range from 10 to 1000 ng/mL for ritonavir and 40 to 4000 ng/mL for nirmatrelvir, with coefficients of correlation above 0.99 for all analytes. Intra-/interday imprecisions were below 10%. The analytical method also meets criteria of matrix effect, carryover, dilution integrity, and stability. In the context of a SARS-CoV-2 infection in a renal transplant recipient, we present a case of tacrolimus overdose with serious adverse events despite discontinuation of nirmatrelvir and ritonavir. The patient had still effective concentrations of nirmatrelvir and tacrolimus 4 days after drug discontinuation. This method was successfully applied for therapeutic drug monitoring in clinical practice.

Drug-induced panic attacks: Analysis of cases registered in the French pharmacovigilance database.

BACKGROUND: The potential role of drugs in the onset of panic attacks (PAs) is poorly understood. AIM: The objective of our study was to characterize drug-induced PAs. METHOD: We performed an analysis of PAs registered in the French pharmacovigilance database between 01/01/1985 and 05/11/2014. RESULTS: Among the 163 recorded cases, 136 (83.4%) were directly related to drugs, mainly antidepressants (11.3%, mainly serotonin reuptake inhibitors), mefloquine (7.2%), isotretinoin (5.2%), rimonabant (3.6%) and corticosteroids (4.7%). PAs are labelled in the Summary of Product Characteristics (SmPC) for a minority (8.6%) of these drugs. In 31.4% of these cases, withdrawal of the suspected drug was performed more than a week after the onset of PAs. PAs could also be secondary to another adverse drug reaction (ADR; n = 14, 8.6%), mainly an allergy to antineoplastic or immunomodulating agents. In 13 cases (8.0%), PAs occurred during a drug-withdrawal syndrome, mainly after benzodiazepines or opioids. Most cases (73%) involved patients without any previous psychiatric disorder. CONCLUSION: This is the first pharmacoepidemiological study about iatrogenic PAs. Beside antidepressants, the most often encountered drugs are not indicated for psychiatric diseases. This study also reveals that iatrogenic PAs mostly occur in patients without any psychiatric medical history and that PAs can be triggered by another ADR. Lastly, the many cases with delayed management underline the need to raise awareness of this relatively unknown ADR among physicians, especially since PAs are generally not labelled in SmPCs of the suspected drugs.

Population pharmacodynamic modeling and simulation of the respiratory effect of acetazolamide in decompensated COPD patients.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) patients may develop metabolic alkalosis during weaning from mechanical ventilation. Acetazolamide is one of the treatments used to reverse metabolic alkalosis. METHODS: 619 time-respiratory (minute ventilation, tidal volume and respiratory rate) and 207 time-PaCO2 observations were obtained from 68 invasively ventilated COPD patients. We modeled respiratory responses to acetazolamide in mechanically ventilated COPD patients and then simulated the effect of increased amounts of the drug. RESULTS: The effect of acetazolamide on minute ventilation and PaCO2 levels was analyzed using a nonlinear mixed effect model. The effect of different ventilatory modes was assessed on the model. Only slightly increased minute ventilation without decreased PaCO2 levels were observed in response to 250 to 500 mg of acetazolamide administered twice daily. Simulations indicated that higher acetazolamide dosage (>1000 mg daily) was required to significantly increase minute ventilation (P<.001 vs pre-acetazolamide administration). Based on our model, 1000 mg per day of acetazolamide would increase minute ventilation by >0.75 L min(-1) in 60% of the population. The model also predicts that 45% of patients would have a decrease of PaCO2>5 mmHg with doses of 1000 mg per day. CONCLUSIONS: Simulations suggest that COPD patients might benefit from the respiratory stimulant effect after the administration of higher doses of acetazolamide.

A life-threatening ectopic pregnancy with etonogestrel implant.

BACKGROUND: Etonogestrel contraceptive implant is a highly effective subdermal method of long-acting hormonal contraception for women. CASE: We describe a case of ruptured ectopic pregnancy occurring in a patient with an etonogestrel contraceptive implant (Implanon®). The only factor predisposing to a failure in this case is a moderately elevated body mass index of 29. However, the implant was in place for less than 2 years, and the plasma levels of etonogestrel were within the expected range. CONCLUSION: This case report emphasizes the fact that ectopic pregnancy should not be formally ruled out in women using this contraceptive, and it highlights the need for further study of the effect of body weight on this contraceptive method.