In this paper, we investigate certain drug effects on heat transfer in the bloodstream due to the impact of magnetic fields and thermal radiation. Certain medications produce disruption in thermoregulatory processes, fever as a result of the drug's pharmacologic activity, and hypothermia as a result of lowering the temperature. All of this affects the vascular permeability and chemical reactions that happen in the blood flow. In the present investigation, the impact of heat radiation and magnetic fields on the velocity, temperature, and concentration of drug-containing blood in a permeable stretched capillary is investigated. The present problem takes into account the unsteady magnetohydrodynamic behavior of blood through the porous media of cells and tissues surrounding the capillary, as well as variable viscosity, thermal conductivity, and chemical diffusivity. The governing equations of the model are formulated, and the resulting partial differential equation is solved numerically by the fourth-order Runge-Kutta method. The numerical simulations are performed using MATLAB software, and the results are plotted in the form of graphs and tables. It has been observed that the permeability factor boosts blood's velocity, temperature, and concentration profiles while simultaneously lowering skin friction and increasing mass and heat transfer rates. Further, the magnetic field can regulate blood velocity and increase drug concentration at the boundary layer.