Discussion
The commercialization of new drugs for the treatment of SARS-CoV-2
changes the conception and therapeutic management of this infection,
offering alternatives with proven efficacy. The exclusion of kidney
transplant patients from many of the clinical trials increases the
uncertainty regarding the efficacy and safety of these drugs in patients
with this condition, but this should not be a contraindication for their
use, since there are studies that demonstrate benefit when used
appropriately (4, 5).
Regarding the management of tacrolimus interaction with
nirmatrelvir/ritonavir, there is little published evidence. Most studies
(6-8) propose a similar plan of action: discontinue immunosuppressant
before starting treatment with nirmatrelvir/ritonavir, and restart it at
reduced doses, according to tacrolimus blood concentrations. Dose
adjustment of the immunosuppressant during and after antiviral treatment
should always be individualized according to the needs of each patient,
and should be subjected to closer monitoring of tacrolimus blood
concentrations than usual.
The reported case shows the strong elevation of tacrolimus blood
concentrations caused by the interaction with nirmatrelvir/ritonavir,
and its persistence over time, as well as the clinical manifestations
that may develop, exposing the need to establish a standardized protocol
for the management of transplanted patients prescribed these drugs.
The information flow between health care personnel and patients is also
crucial in cases such as the one described in this study, and has an
impact on the patient’s understanding of the modifications to his or her
treatment.