Background The main treatments in a majority of headache patients are pharmacologic therapies. As a result, it is imperative to have strong background in pharmacotherapy used to treat headaches in order to provide optimal therapy and avoid drug interactions. One of the main reasons for failure of pharmacologic treatment of headaches is drug–drug interactions (DDIs). While there are many distinct pathways and mechanisms in which DDIs can occur, most occur through alterations within the cytochrome P450 pathways (CYP). Drugs that cause induction, inhibition, or are simply substrates for these pathways are responsible for many of the DDIs. Aim/Results We review and discuss the important and potential DDIs of commonly used headache medication often encountered in clinical practice. We divide the drugs into two classes, abortive and preventive. Within each group we select the most commonly used drugs and provide a detailed discussion of the mechanisms of interaction for each. Also included are commonly used herbal supplements, which can interact with headache medications. Conclusion Drug–drug‐interactions are a major concern when developing a treatment regimen for patients suffering from headaches. There is a growing need for physician attention to the pharmacokinetics of drugs to improve the quality of patient care. It is vital that prescribing physicians be aware of the DDIs associated with the commonly prescribed headache medications to optimize patient care and therapy results.