Nonisentropic inflation models are characterized by radiation production due to the decay of fields coupled to the inflaton during inflation and that might sustain a thermal radiation bath as a result of the dissipative particle production. The presence of the radiation bath can impact on the dynamics of inflation and, consequently, on the observable quantities measured from the cosmic microwave background radiation. Besides of dissipative effects, these are also accompanied by stochastic fluctuations. In this talk I explain both the origin, in terms of well motivated particle physics models, and the impact of these effects on the inflationary dynamics and on the observable quantities.