Safe and effective telemanipulation of concentric tube robots is hindered by their complex, non-intuitive kinematics. Guidance schemes in the form of attractive and repulsive constraints can simplify task execution and facilitate natural operation of the robot by clinicians. The real-time seamless calculation and application of guidance, however, requires computationally efficient algorithms that solve the non-linear inverse kinematics of the robot and guarantee that the commanded robot configuration is stable and sufficiently away from the anatomy. This paper presents a multi-processor framework that allows on-the-fly calculation of optimal safe paths based on rapid workspace and roadmap pre-computation The real-time nature of the developed software enables complex guidance constraints to be implemented with minimal computational overhead. A user study on a simulated challenging clinical problem demonstrated that the incorporated guiding constraints are highly beneficial for fast and accurate navigation with concentric tube robots.