Coronavirus disease (COVID-19) is a systemic infection targeting multiple organs. Interstitial pneumonia is the landmark feature of this condition. Severe acute respiratory symptoms requiring intensive care support arises for about one out of twenty symptomatic cases. Aminochinolone, antiviral, antibiotic, corticoid, anticoagulant and immunobiological drugs are used, mostly to treat symptoms. Only remdesivir exhibiting weak antiviral activity is approved for COVID-19. Psychotropic medications may interact with medical treatments for COVID-19. The aim of this presentation is to highlight pharmacokinetic and pharmacodynamic drug-drug interactions to be expected for medical treatments of COVID-19. Remdesivir and favipiravir exhibit hepatotoxic properties which may be enhanced under combinations with tricyclic antidepressants or agomelatine. Favipiravir, hydroxychloroquine, chloroquine, azithromycin, lopinavir/ritonavir have QT interval prolongation potential and must be considered for combinations with antidepressant and antipsychotic drugs. For hydroxychloroquine, hypoglycemic activity may give rise to endocrine disturbances. Pharmacokinetic drug-drug interactions can be expected for lopinavir/ritonavir which inhibit cytochrome P-450 (CYP) 3A4 and induce CYP2C9 and CYP2C19. Combinations with psychotropic drugs that are substrates of these enzymes (victim drugs) will affect drug concentrations in blood and lead to supra- or subtherapeutic levels. Moreover, it must be assumed that the COVID-19 infection is associated with an enhanced production of cytokines which has a known impact on CYP enzyme activities. Though studies on interactions between psychotropic medications and medical treatments for COVID-19 are lacking, multiple drug interactions can be predicted and expected considering the side effect profiles and CYP inhibitory, inducing and substrate properties of combined drugs.

The present study evaluates for the first time in dogs, the kinetics of green tea catechins and their metabolic forms in plasma and urine. Ten beagles were administered 173 mg (12·35 mg/kg body weight) of catechins as a green tea extract, in capsules. Blood samples were collected during 24 h after intake and urine samples were collected during the following periods of time: 0–2, 2–6, 6–8 and 8–24 h. Two catechins with a galloyl moiety and three conjugated metabolites were detected in plasma. Most of the detected forms in plasma reached their maximum plasma concentration (Cmax) at around 1 h. Median Cmax for ( − )-epigallocatechin-3-gallate (EGCG), ( − )-epicatechin-3-gallate (ECG), ( − )-epigallocatechin glucuronide (EGC-glucuronide), ( − )-epicatechin glucuronide (EC-glucuronide), ( − )-epicatechin sulphate (EC-sulphate) were 0·3 (range 0·1–1·9), 0·1 (range 0–0·4), 0·8 (range 0·2–3·9), 0·2 (range 0·1–1·7) and 1 (range 0·3–3·4) μmol/l, respectively. The areas under the plasma concentration v. time curves (AUC0 → 24) were 427 (range 102–1185) μmol/l × min for EGC-glucuronide, 112 (range 53–919) μmol/l × min for EC-sulphate, 71 (range 26–306) μmol/l × min for EGCG, 40 (range 12–258) μmol/l × min for EC-glucuronide and 14 (range 0·1–124) μmol/l × min for ECG. The values of mean residence time (MRT0 → 24) were 5 (range 2–16), 2 (range 1–11), 10 (range 2–13), 3 (range 2–16) and 2·4 (range 1–18) h for EGCG, ECG, EGC-glucuronide, EC-glucuronide and EC-sulphate, respectively. In urine, catechins were present as conjugated forms, suggesting bile excretion of EGCG and ECG. Green tea catechins are absorbed following an oral administration and EGC-glucuronide is the metabolic form that remains in the organism for a longer period of time, suggesting that this compound could suffer an enterohepatic cycle.