Is concomitant medication allowed for subjects in clinical trials?

Concomitant medication refers to the drugs that the subjects take at the same time as the trial drugs in clinical trials. The concomitant medication (nature, dose, etiology, start and end dates) in all trials must be recorded in detail. The principle of taking concomitant medication is that the concomitant medication used in the trial cannot affect the evaluation of the trial drug. For example, in a trial evaluating a new non steroidal anti-inflammatory drug for pain treatment, patients cannot take aspirin at the same time. It is allowed to take concomitant medication without affecting the trial drug. The test plan should clearly specify which drugs can be taken at the same time and which drugs cannot be taken at the same time. Sometimes, drugs that do not affect experimental drugs are also included in the scope of prohibition, and researchers can question this. However, once the test plan is finalized, even if the researcher believes that some requirements are inappropriate, they must be strictly followed. A big problem with concomitant medication is when patients take over-the-counter drugs without timely reporting to the investigator. In addition, non drug treatment will also affect the trial results. For example, some patients received physical or acupuncture treatment while others did not, so the response of different patients to the trial drugs will result in different results due to different concomitant treatments. In trials in which healthy subjects participate (such as phase I clinical trials), the food and beverage standards of subjects should be unified, because diet may affect the absorption of drugs for trials. The administrative authority will require to check the list of concomitant drugs taken by the subjects in the trial and check it with the subjects' medical records and other original data to determine that all conclusions about the efficacy of the drugs used in the trial have nothing to do with the concomitant drugs taken by the patients.