Are there any good medications used commonly to help with ptsd associated with sexual abuse?

Maybe: Medications that help ptsd in general will help it regardless of the cause of the trauma. Sexual trauma requires a good deal of additional psychotherapy or cognitive behavioral therapy in many sufferers.

Yes: Prazosin can be very effective for nightmares and for hyperarousal if combat-related. Ssri's help "modify information taken in" more appropriately and help extinguish fear reaction. Also helps anxiety, depression, panic, aggression, and suicidal thoughts. These appear to work better for non-combat-ralted trauma. Any associated medical or emotional problem should be aggressively treated with med.

OCD: I would say medication effectiveness has little if anything to do with the specific source of trauma, per se. I would submit that medication, at its best, takes the edge off symptoms. The real grunt work takes place in psychotherapy.