$Unique_ID{BRK02023}
$Pretitle{}
$Title{METHENAMINE}
$Subject{Hiprex (Merrell Dow)
Mandameth (Major)
Mandelamine (Parke-Davis)
methenamine mandelate (various manufacturers)
Urex (Riker)}
$Volume{}
$Log{
Urex*0202301.scf}

Copyright (C) 1991 Publications International, Ltd.


METHENAMINE
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BRAND NAMES (Manufacturers):
     Hiprex (Merrell Dow)
     Mandameth (Major)
     Mandelamine (Parke-Davis)
     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.  It is chemically converted in the bladder to ammonia and
formaldehyde, which kills actively growing bacteria.

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.
     Methenamine works best when the level of medicine in your bloodstream and
urine is kept constant.  It is best, therefore, to take the doses at evenly
spaced intervals day and night.  For example, if you are to take four doses a
day, the doses should be spaced six hours apart.
     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.

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.  This medication may not be effective for your infection.
     * 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 (nonacidic), such as citrus fruits and milk products.
Your doctor may also want you to take vitamin C (ascorbic acid) 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.

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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.
