It is vasodilators and uterine relaxants. It is used in the treatment of premature labor (when the uterus starts contracting for birth too early than usual). It is also helpful in the treatment of peripheral vascular diseases. Isox 40mg Tablet can be taken with or without food, but take it at the same time to get the most benefit. It should be taken as your doctor's advice. The dose and how often you take it depends on what you are taking it for. Your doctor will decide how much you need to improve your symptoms. Swallow the tablets whole with a drink of water. You should take this medicine for as long as it is prescribed for you. Dizziness is the most common side effect of the medicine. If these bother you or appear serious, let your doctor know. To lower the chance of dizziness, you must rise slowly, if getting up from sitting or lying position or avoid driving or attention requiring activities. Before taking the medicine, tell your doctor if you have ever had heart problems or bleeding disorder. Your doctor should also know about all other medicines you are taking as many of these may make this medicine less effective or change the way it works. You must avoid taking part in any strenuous or stressful activities to prevent premature labor.