Welcome and thanks for the consult. I appreciate your concerns. I have reviewed your question about your recent change of medications. Imdur 30mg may cause feeling of lightheaded, dizziness and fainting that combined with other drugs may give the feeling of fatigue. You need to consult back your treating Physician in order to reevaluate the drugs and dosages prescribed. If not managed this way, chances are that it may persist to some extent. Cartia itself causes dizziness, lightheadedness, fatigue and other such symptoms. Combined with Imdur, it exaggerates this effect. But it never means that you were mistreated. Your Physician knows better about your complete health scenario. Don t stop taking any drug without consultation from your prescribing Physician. Hope it helps. Ask for more if you have doubts or questions. My direct and quick link is: tinyurl.com/drhanifmd Regards!