Could taking zoloft, risperidone and zantac together cause high blood pressure?

Sort of: It would not cause chronic hypertension in a classical sense. The is a condition called serotonin syndrome that can occur with zoloft and risperdone which is pathological and includes many oter symptoms including agitation, twitching, abnormal vital signs and mental status changes to seizures and coma. SO yes it could but it would be part other more serious symptoms.