Taking Paclitaxel together with Efavirenz is not recommended. Efavirenz can lower the amount of Paclitaxel in your body, so Paclitaxel may not work as well as it should. If you take both, tell your doctor so they can decide what is best for you.
These medicines can affect each other in a serious way. Do not start taking them together unless your doctor has said it is OK. If you already take both, do not stop either one on your own: speak to your doctor or pharmacist soon.