Ephedra may raise your blood pressure. Do not use ephedra in hot temperatures or during extreme aerobic workouts.

Do not take Ephedra if you have high blood pressure, high pressure in the eyes (glaucoma), weakened blood vessels in the brain, prostate cancer, an overactive adrenal gland, or a thyroid disorder. In general, avoid Ephedra if you have any condition that makes you anxious or restless. Combining Ephedra with a variety of other medications can lead to potentially serious problems. For example, when taken in combination with heart drugs such as digitalis or digoxin (Lanoxin), Ephedra is more likely to disturb the rhythm of the heart. Combining Ephedra with the blood pressure medication guanethidine (Ismelin) can dangerously exaggerate the herb's stimulative effects. A similar problem is possible when Ephedra is combined with drugs classified as MAO inhibitors, such as the antidepressants Nardil and Parnate and the Parkinson's disease medication Eldepryl. The combination of Ephedra and ergot-based drugs such as migraine remedies Ergomar and Wigraine can result in high blood pressure.