Isoniazid Tablets

DRUG DESCRIPTION

Isoniazid is an antibacterial available as 100 mg and 300 mg tablets for oral administration. Each tablet also contains as inactive ingredients: colloidal silicon dioxide, lactose monohydrate, pregelatinized starch, povidone, and stearic acid.

Isoniazid is chemically known as isonicotinyl hydrazine or isonicotinic acid hydrazide. It has an empirical formula of C6H7N3O and a molecular weight of 137.14. It has the following structure:

Isoniazid structural formula illustration

Isoniazid is odorless, and occurs as a colorless or white crystalline powder or as white crystals. It is freely soluble in water, sparingly soluble in alcohol, and slightly soluble in chloroform and in ether. Isoniazid is slowly affected by exposure to air and light.

What are the possible side effects of isoniazid ()?

If you experience any of the following serious side effects, stop taking isoniazid and seek emergency medical attention or contact your doctor immediately:

  • an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);
  • unusual weakness or fatigue;
  • nausea, vomiting, or loss of appetite;
  • abdominal pain;
  • yellow skin or eyes;
  • dark urine;
  • numbness or tingling in your hands or feet;
  • seizures;
  • blurred...

Read All Potential Side Effects and See Pictures of Isoniazid Tablets

What are the precautions when taking isoniazid (Isoniazid Tablets)?

See also Warning section.

Before taking isoniazid, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: previous severe reaction from isoniazid (such as liver disease), liver disease, alcohol use, HIV infection, kidney disease, diabetes, numbness/tingling of arms/legs (peripheral neuropathy), recent childbirth.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Alcohol may...

Read All Potential Precautions of Isoniazid Tablets


Isoniazid Tablets Consumer (continued)

SIDE EFFECTS: See also Warning section.

Nausea/vomiting or stomach upset may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur: numbness/tingling of arms/legs, painful/swollen joints.

Tell your doctor immediately if any of these rare but serious side effects occur: change in the amount of urine, increased thirst/urination, vision changes, easy bruising/bleeding, signs of a new infection (such as fever, persistent sore throat), mental/mood changes (such as confusion, psychosis), seizures.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: See also Warning section.

Before taking isoniazid, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: previous severe reaction from isoniazid (such as liver disease), liver disease, alcohol use, HIV infection, kidney disease, diabetes, numbness/tingling of arms/legs (peripheral neuropathy), recent childbirth.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Alcohol may increase the risk of liver disease. Avoid alcoholic beverages while using this medication.

This product may cause live bacterial vaccines (such as BCG vaccine) not to work as well. Therefore, do not have any immunizations/vaccinations while using this medication without the consent of your doctor.

Liquid forms of this medication may contain sugar. Caution is advised if you have diabetes or any other condition that requires you to limit/avoid sugar. Ask your doctor or pharmacist about using this product safely.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This product passes into breast milk but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.


Isoniazid Tablets Patient Information Including Side Effects

Brand Names:

Generic Name: isoniazid (Pronunciation: eye so NYE a zid)

  • What is isoniazid ?
  • What are the possible side effects of isoniazid ?
  • What is the most important information I should know about isoniazid ?
  • What should I discuss with my healthcare provider before taking isoniazid ?
  • How should I take isoniazid ?
  • What happens if I miss a dose ?
  • What happens if I overdose ?
  • What should I avoid while taking isoniazid ?
  • What other drugs will affect isoniazid ?
  • Where can I get more information?

What is isoniazid ?

Isoniazid is an antibiotic. It prevents tuberculous bacteria from multiplying in the body.

Isoniazid is used to treat and to prevent tuberculosis (TB).

Isoniazid may also be used for purposes other than those listed in this medication guide.

What are the possible side effects of isoniazid ?

If you experience any of the following serious side effects, stop taking isoniazid and seek emergency medical attention or contact your doctor immediately:

  • an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);
  • unusual weakness or fatigue;
  • nausea, vomiting, or loss of appetite;
  • abdominal pain;
  • yellow skin or eyes;
  • dark urine;
  • numbness or tingling in your hands or feet;
  • seizures;
  • blurred vision; or
  • confusion or abnormal behavior.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome. You may report side effects to FDA at 1-800-FDA-1088.

What is the most important information I should know about isoniazid ?

Take all of the isoniazid that has been prescribed for you even if you begin to feel better. Your symptoms may begin to improve before the infection is completely treated.

Avoid alcohol while taking isoniazid. Alcohol may increase the risk of damage to the liver during isoniazid treatment.

Contact your doctor immediately if you experience numbness or tingling in the hands or feet, weakness, fatigue, loss of appetite, nausea and vomiting, yellowing of the skin or eyes, or darkening of the urine.

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