Hi, Diomox contains acetazolamide which belongs to the group of medications known as carbonic anhydrase inhibitors is used to treat and prevent the symptoms of altitude sickness. This medication is also used with other medications to treat high pressure inside the eye due to certain types of glaucoma. It is used with other medication to treat certain types of seizures too. Side effects of Diomox are nausea, vomiting, diarrhoea, changes in taste, dry mouth, drowsiness, blurred vision, anorexia, dizziness, tiredness, lightheadedness, increased urination, fatigue, flushing, tingling sensation of extremities, allergic reactions etc. Take plenty of fluids to prevent dehydration and other complications. For vomiting and nausea or sickness, you can take antiemetics. If these side effects persist for long or bother you, then you should contact your doctor immediately for medical help. There are no sufficient evidence based studies about the effects of Diomox on menstrual cycle. But from the some users of Diomox, it was heard that Diomox had stopped their menstrual cycles during their using of Diomox. Take care. Hope I have answered your questions. Let me know if I can assist you further. Regards, Dr. Zubayer Alam, General And Family Physician