$Unique_ID{BRK03194}
$Pretitle{}
$Title{isoniazid}
$Subject{Laniazid Lannett Nydrazid Apothecon Antitubercular isoniazid
tuberculosis bacteria}
$Volume{}
$Log{}

Copyright (C) 1993 Publications International, Ltd.


isoniazid
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BRAND NAMES (Manufacturers)

     isoniazid (various manufacturers)
     Laniazid (Lannett)
     Nydrazid (Apothecon)

TYPE OF DRUG

     Antitubercular

INGREDIENT

     isoniazid

DOSAGE FORMS

     Tablets (50 mg, 100 mg, and 300 mg)
     Oral syrup (50 mg per 5-ml spoonful)

STORAGE

     Store at room temperature in a tightly closed, light-resistant container.
This medication should never be frozen.

USES

     Isoniazid is used to prevent and treat tuberculosis.  It acts by severely
injuring the cell structure of tuberculosis bacteria, thereby preventing them
from growing and multiplying.

TREATMENT

     In order to avoid stomach irritation, you can take isoniazid with food or
a full glass of water or milk (unless your doctor directs you to do
otherwise).
     Antacids prevent the absorption of isoniazid from the gastrointestinal
tract, so they should not be taken within an hour of a dose of isoniazid.
     Each dose of the oral syrup should be measured carefully with a specially
designed 5-ml measuring spoon.  An ordinary kitchen teaspoon is not accurate
enough for medical purposes.
     It is important to continue to take this medication for the entire time
prescribed by your doctor, even if your symptoms disappear before the end of
that period.  If you stop taking the drug too soon, your infection could
recur.
     It is common for therapy to last for at least six months and, at times,
for as long as two years.
     Try not to miss any doses of this medication.  If you do miss a dose,
take the missed dose as soon as possible, unless it is almost time for the
next dose.  In that case, do not take the missed dose at all; just return to
your regular dosing schedule.  Do not double the next dose.

SIDE EFFECTS

     Minor.

     Abdominal pain, dizziness, heartburn, nausea, or vomiting.  These side
effects should disappear as your body adjusts to the medication.
     If you feel dizzy, sit or lie down for a while; get up slowly from a
sitting or reclining position, and be careful on stairs.

     Major.

     Tell your doctor about any side effects that are persistent or
particularly bothersome.  IT IS ESPECIALLY IMPORTANT TO TELL YOUR DOCTOR about
blurred vision, breast enlargement (in both sexes), chills, darkening of the
urine, eye pain, fever, malaise, memory impairment, numbness or tingling in
the fingers or toes, rash, unusual bleeding or bruising, vision changes,
weakness, or yellowing of the eyes or skin.
     Your doctor may want to prescribe vitamin B6 (pyridoxine) to prevent the
numbness and tingling.  However, do not take vitamin B6 without consulting
your doctor.

INTERACTIONS

     Isoniazid interacts with several other types of medications:
     1. Concurrent use of isoniazid and alcohol can lead to decreased
effectiveness of isoniazid and increased side effects on the liver.
     2. The combination of isoniazid and cycloserine can result in dizziness
or drowsiness.
     3. The combination of isoniazid and disulfiram can lead to dizziness,
loss of coordination, irritability, and insomnia.
     4. Isoniazid can decrease the breakdown of phenytoin and carbamazepine in
the body, which can lead to an increase in side effects from phenytoin and
carbamazepine.
     5. Isoniazid can decrease the effectiveness of ketoconazole.
     6. In combination, rifampin and isoniazid can increase the risk of liver
damage.  However, this is a commonly prescribed combination.
     7. The effectiveness of isoniazid may be decreased by
adrenocorticosteroids (cortisone-like medicines).
     8. The side effects of benzodiazepine tranquilizers or meperidine may be
increased by isoniazid.
     BE SURE TO TELL YOUR DOCTOR about any medications you are currently
taking, especially those listed above.

WARNINGS

     * Tell your doctor about unusual or allergic reactions you have had to
any medications, especially to isoniazid, ethionamide, pyrazinamide, or niacin
(vitamin B3).
     * Before starting to take this medication, be sure to tell your doctor if
you have a history of alcoholism, or if you now have or ever had kidney
disease, liver disease, or seizures.
     * If this drug makes you dizzy, avoid tasks that require alertness, such
as driving a car.
     * Your doctor may want you to have periodic eye examinations while taking
this medication, especially if you begin to have vison side effects.
     * Isoniazid can interact with several foods (skipjack fish, tuna, yeast
extracts, sauerkraut juice, sausages, and certain cheeses), leading to severe
reactions.  You should, therefore, avoid eating these foods while being
treated with isoniazid.
     * Diabetics using Clinitest urine glucose tests may get erroneously high
sugar readings while they are taking isoniazid.  Temporarily changing to
Clinistix or Tes-Tape urine tests avoids this problem.
     * Be sure to tell your doctor if you are pregnant.  Although isoniazid
appears to be safe during pregnancy, it does cross the placenta.  Extensive
studies in pregnant women have not been conducted.  Also, tell your doctor if
you are breastfeeding an infant.  Small amounts of isoniazid 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.