Darrell W. Gonzales, MD

Many of the Proactiv products contain either benzoyl peroxide or salicylic acid.  These products can work for acne, but they can also generate some dryness and irritation to the skin. 

Tazorac is a topical retinoid that may also work well for controlling acne bumps and comedones, but for many people it can be very irritating and cause excessive dryness, peeling, and redness. 

If you combine both the Proactiv products with the Tazorac you might substantially increase your risk of irritation.  If you believe that the combination of therapy has improved your skin, but leaves you dry and irritated, it is okay to use a light moisturizer, such as Cetaphil.  

Besides causing an increased risk of irritation, combining these products should be fine.  Don't forget that applying Tazorac may increase your risk of sun sensitivity while using it and careful photoprotection should be practiced.  Good luck!