  Paxlovid is a promising, orally bioavailable novel drug for SARS--CoV--2 with
excellent safety profiles. Our main goal here is to explore the pharmacometric
features of this new antiviral. To provide a detailed assessment of Paxlovid,
we propose a hybrid multiscale mathematical approach. We demonstrate that the
results of the present \textit{in silico} evaluation match the clinical
expectations remarkably well: on the one hand, our computations successfully
replicate the outcome of an actual \textit{in vitro} experiment; on the other
hand we verify both the sufficiency and the necessity of Paxlovid's two main
components (nirmatrelvir and ritonavir) for a simplified \textit{in vivo} case.
Moreover, in the simulated context of our computational framework we visualize
the importance of early interventions, and identify the time window where a
unit--length delay causes the highest level of tissue damage. Finally, the
results' sensitivity to the diffusion coefficient of the virus is explored in
details.
