$Unique_ID{BRK03224} $Pretitle{} $Title{methenamine} $Subject{Hiprex Merrell Dow Mandameth Major Mandelamine Parke-Davis hippurate mandelate Urex Riker Antibiotic methenamine bacterial infections urinary tract} $Volume{} $Log{ Urex*0322401.scf} Copyright (C) 1993 Publications International, Ltd. methenamine ------------------------------------------------------------------------------ BRAND NAMES (Manufacturers) Hiprex (Merrell Dow) Mandameth (Major) Mandelamine (Parke-Davis) methenamine hippurate (various manufacturers) methenamine mandelate (various manufacturers) Urex (Riker) TYPE OF DRUG Antibiotic INGREDIENT methenamine DOSAGE FORMS Tablets (500 mg and 1 g) Enteric-coated tablets (500 mg and 1 g). Oral suspension (250 mg and 500 mg per 5-ml spoonful) Oral granules (1 g packets) STORAGE Methenamine tablets, oral suspension, and granules should be stored at room temperature in tightly closed containers. This medication should never be frozen. USES Methenamine is used to prevent and treat bacterial infections of the urinary tract. TREATMENT In order to avoid stomach irritation, you should take methenamine with food or with a full glass of water or milk (unless your doctor directs you to do otherwise). The oral suspension form of this medication should be shaken well just before measuring each dose. The contents tend to settle on the bottom of the bottle, so it is necessary to shake the container to distribute the ingredients evenly and equalize the doses. Each dose should then be measured carefully with a specially designed 5-ml measuring spoon. An ordinary kitchen teaspoon is not accurate enough. The enteric-coated tablets should be swallowed whole. Breaking, crushing, or chewing these tablets increases their gastrointestinal side effects. If you are taking the oral granules, the contents of the packet should be dissolved in two to four ounces of water just before you take the dose. Try not to miss any doses of this medication. If you do miss a dose, take it immediately. However, if you do not remember to take the missed dose until it is almost time for your next dose, take the missed dose immediately; space the following dose about halfway through the regular interval between doses; and then continue with your regular dosing schedule. It is important to continue to take this medication for the entire time prescribed by your doctor (usually seven to 14 days), even if the symptoms disappear before the end of that period. If you stop taking the drug too soon, resistant bacteria are given a chance to continue growing, and the infection could recur. This medication works best when your urine is acidic (ph 5.5 or below). You may want to talk to your doctor about testing the acidity of your urine before you begin treatment with methenamine. SIDE EFFECTS Minor. Abdominal cramps, diarrhea, headache, loss of appetite, nausea, or vomiting. These side effects should disappear as your body adjusts to the medication. Major. Tell your doctor about any side effects that are persistent or particularly bothersome. IT IS ESPECIALLY IMPORTANT TO TELL YOUR DOCTOR about difficulty in breathing, difficult or painful urination, itching, mouth sores, rapid weight gain (three to five pounds within a week), shortness of breath, or skin rash. INTERACTIONS Methenamine interacts with several other types of medications: 1. Sodium bicarbonate, antacids, acetazolamide, and diuretics (water pills) can decrease the effectiveness of methenamine by preventing its conversion to formaldehyde. 2. Methenamine can increase the side effects (to the kidneys) of sulfonamide antibiotics. Before starting to take methenamine, BE SURE TO TELL YOUR DOCTOR about any medications you are currently taking, especially any of those listed above. WARNINGS * Tell your doctor about unusual or allergic reactions you have had to any medications, especially to methenamine. * Before starting to take methenamine, be sure to tell your doctor if you now have or if you have ever had dehydration, kidney disease, or liver disease. * Some of these products contain the color additive FD&C Yellow No. 5 (tartrazine), which can cause allergic-type reactions (fainting, rash, shortness of breath) in certain susceptible individuals. * This medication has been prescribed for your current infection only. Another infection later on, or one that someone else has, may require a different medicine. You should not give your medicine to other people or use it for other infections, unless your doctor specifically directs you to do so. * If the symptoms of your infection do not improve in several days, CONTACT YOUR DOCTOR. * In order for this medication to work properly, it is necessary that your urine remain acidic. You should, therefore, avoid foods that cause the urine to become alkaline such as milk products. Your doctor may also want you to take vitamin C to help keep the urine acidic. * Be sure to tell your doctor if you are pregnant. Although methenamine appears to be safe during pregnancy, it does cross the placenta, and extensive studies have not been conducted. Also, tell your doctor if you are breast-feeding an infant. Small amounts of methenamine pass into breast milk. ---------------- The material contained here is "FOR INFORMATION ONLY" and should not replace the counsel and advice of your personal physician. Promptly consulting your doctor is the best path to a quick and successful resolution of any medical problem.