Diamox (acetazolamide) is commonly used to prevent or treat altitude sickness and is generally safe for most people. Your allergy to Monocef (ceftriaxone, an antibiotic) does not usually mean you will be allergic to Diamox, as they are different types of medicines. However, Diamox is related to sulfa drugs, so it should be used with caution if you have a known sulfa allergy. It can cause side effects like frequent urination, altered taste, or mild dizziness, which are usually temporary. Before taking it, it is best to consult a doctor, especially if you have kidney problems, breathing issues, or are on other medications. Also, remember that gradual ascent, proper hydration, and rest are very important to prevent altitude sickness, and medicines are only an additional support if needed.