Glaucoma is a group of eye conditions in which fluid builds up in your eye causing gradual vision loss. Ocular migraine Ocular migraine usually refers to a type of migraine that can cause temporary blindness in one eye.
Increased Blood Pressure. The combination of caffeine and ephedrine can increase your blood pressure. Ephedrine and caffeine stimulate your sympathetic nervous system by increasing neurotransmitters, such as norepinephrine. This stimulant effect can increase your blood pressure by constricting your blood vessels. This is why many diet pill formulas, often called an ECA stack, contain ephedrine, caffeine and aspirin to thin your blood to offset the blood vessel constriction.
Diabetes: Some research suggests that the caffeine in guarana may affect the way people with diabetes process sugar (glucose) and may complicate blood sugar control. There is also some interesting research that suggests caffeine may enhance the warning symptoms of low blood sugar in patients with type 1 diabetes.t typical doses, the caffeine in guarana can cause insomnia, nervousness and restlessness, stomach irritation, nausea, vomiting, increased heart rate and blood pressure, rapid breathing, tremors, delirium, diuresis, and other side effects.