We incorporate the model of drug action presented in Huijben et al. (2013), which was parameterized to describe the consequences of pyrimethamine for Plasmodium chabaudi parasites (Landau, 1965) in infections of female C57BL6 mice (Schneider et al., 2012). According to this model, as long as the drug is present at a sufficiently high concentration in the host, it kills a fixed proportion (94%) of parasites each day. The underlying within‐host model assumed in Huijben et al. (2013) was in discrete‐time and cohorts of infected cells burst synchronously. To approximate this drug action in our model, we apply an additional death rate, μd, to infected cells. By setting μd=−ln(1−0.94)=2.81, we ensure that ∼94% of infected cells die within the 1 day parasite developmental cycle. Different drug doses, d, modify the length of drug action, L, beyond the days the drug was administered (see Figure A.1 in Appendix A, for how L varies with dose):(9)L=3.557−2.5861+e−8.821+d.