Sotret Gel contains Isotretinoin 0.05%. Sotret is a generic gel for branded Isotrex and Isotrexin topical isotretinoin gels. Tretinoin and isotretinoin are the sound-alikes generic names for two different medications. Both are used to treat acne and both belong to a group of medications called retinoids. Retinoids are medications that are derived from vitamin A.