Isoniazid

Description

Isoniazid is an anti-bacterial medicine that is used to treat tuberculosis. It is usually taken in combination with other medicines to prevent the spread of the infection. It is important to continue treatment with this medicine even if you feel well; do not stop the use of this medicine without consulting your doctor.

Side effects

Major & minor side effects for Isoniazid

  • Dark urine
  • Loss of appetite
  • Nausea or Vomiting
  • Unusual tiredness or weakness
  • Tingling or numbness of the hands and feet
  • Convulsions (seizures)
  • Mental depression
  • Joint pain
  • Skin Rash
  • Unusual bleeding or bruising

Uses of Isoniazid

What is it prescribed for?

  • Tuberculosis
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Concerns

Commonly asked questions

  • Onset of action
    The amount of time required for this medicine to show its action is not clinically established.
  • Duration of effect
    The amount of time for which this medicine remains active in the body is not clinically established.
  • Safe with alcohol?
    Alcohol should not be consumed while receiving this medicine since it may significantly increase the risk of serious adverse effects. These adverse effects may include unusual bleeding or bruising, joint pain or swelling, fever, chills, skin rash, severe abdominal pain, yellowing of the skin or eyes, etc.
  • Is it habit forming?
    No habit-forming tendencies were reported.
  • Usage in pregnancy?
    This medicine is not recommended for use in pregnant women unless necessary. All the risks and benefits should be discussed with the doctor before taking this medicine.
  • Usage while breast-feeding?
    This medicine is not recommended for use in breastfeeding women unless necessary. All the risks and benefits should be discussed with the doctor before taking this medicine. If the medicine is used, appropriate vitamin B6 supplementation should be taken by the mother under the supervision of the doctor.

Allergy

This medicine is not recommended for use in patients with a known allergy to isoniazid or any other inactive ingredients present along with this medicine.
Warnings for special population

Pregnancy

This medicine is not recommended for use in pregnant women unless necessary. All the risks and benefits should be discussed with the doctor before taking this medicine.

Breast-feeding

This medicine is not recommended for use in breastfeeding women unless necessary. All the risks and benefits should be discussed with the doctor before taking this medicine. If the medicine is used, appropriate vitamin B6 supplementation should be taken by the mother under the supervision of the doctor.
General warnings

Liver impairment

This medicine should be used with caution in patients with a known history of liver diseases due to the increased risk of worsening of the patient's condition. Close monitoring of liver function tests, appropriate dose adjustments, or replacement with a suitable alternative may be required based on the clinical condition of the patient.

Renal impairment

This medicine should be used with caution in patients with a known history of renal diseases due to the increased risk of severe adverse effects. Close monitoring of kidney function tests, appropriate dose adjustments, or replacement with a suitable alternative may be required based on the clinical condition of the patient.

Missed Dose

Oral Formulations: The missed dose should be taken as soon as possible. It is advisable to skip the missed dose if it is already time for your next scheduled dose. Do not double your dose to make up for the missed one. Injection: Since this medicine is administered by a qualified healthcare professional in the clinical or hospital setting, the likelihood of missing a dose is very low. If you miss an appointment for receiving this medicine, contact your doctor immediately.

Overdose

Oral Formulations: Seek emergency medical treatment or contact the doctor in case of an overdose. Injection: Since this medicine is administered in the hospital or clinical setting by a qualified healthcare professional, the likelihood of an overdose is very low. However, emergency medical treatment will be initiated by the doctor if an overdose is suspected.
All drugs interact differently for person to person. You should check all the possible interactions with your doctor before starting any medicine.
Interaction with Alcohol

Description

N/A

Instructions

Alcohol should not be consumed while receiving this medicine since it may significantly increase the risk of serious adverse effects. These adverse effects may include unusual bleeding or bruising, joint pain or swelling, fever, chills, skin rash, severe abdominal pain, yellowing of the skin or eyes, etc.
Interaction with Medicine

Pimozide

Leflunomide

Halothane

Teriflunomide

Citalopram

Rifampicin

Disease interactions

Hepatotoxicity

This medicine is not recommended for use in patients with an acute liver disease or a known history of liver injury due to isoniazid. It should be used with caution in patients with chronic liver diseases or a history of alcoholism due to the increased risk of serious liver injuries which may be fatal. Close monitoring of liver function tests is recommended for such patients. Appropriate dose adjustments or replacement with a suitable alternative may be necessary based on the clinical condition of the patient.

Peripheral Neuropathy

This medicine should be used with caution in patients with a known history of peripheral neuropathy due to the increased risk of worsening of the patient's condition. Appropriate corrective measures including vitamin B6 supplementation, dose adjustments, or replacement with a suitable alternative may be required in some cases based on the clinical condition.

Renal Dysfunction

This medicine should be used with caution in patients with a known history of renal diseases due to the increased risk of severe adverse effects. Close monitoring of kidney function, appropriate dose adjustments, or replacement with a suitable alternative may be required in some cases based on the clinical condition of the patient.
Food interactions
This medicine should be taken on an empty stomach, at least 1-2 hours before or after a meal since food decreases the absorption of this medicine.
Lab interactions
Information not available.
Oral Formulations: Take this medicine exactly as prescribed by your doctor. Do not take in larger or smaller amounts than advised/prescribed. Consult the doctor if you experience any undesirable side effects. Ensure that the treatment course is completed. Do not stop the use of this medicine without consulting your doctor. Injection: This medicine should be administered by a qualified healthcare professional in the clinical or hospital setting. Inform the doctor if you have a known history of allergy to this medicine. Report to the doctor all your current medicines as well as your medical conditions before receiving this medicine. Ensure that the treatment course is completed; do not miss an appointment to receive an injection of this medicine.
Miscelleneous

To be taken on an empty stomach

To be taken as instructed by doctor

Does not cause sleepiness

How it works
This medicine works by inhibiting bacterial cell wall synthesis; this stops the growth of the bacteria and ultimately leads to their death.
Legal Status

Approved

Approved

Approved

Approved

Classification

Category

Hydrazide derivatives

Schedule

Schedule H

[Internet]. 2018 [cited 15 March 2018]. Available from:

https://www2.medicines.org.uk/emc/medicine/25256

Isoniazid - DrugBank [Internet]. Drugbank.ca. 2018 [cited 15 March 2018]. Available from:

https://www.drugbank.ca/drugs/DB00951

DailyMed - ISONIAZID- isoniazid tablet [Internet]. Dailymed.nlm.nih.gov. 2018 [cited 15 March 2018]. Available from:

https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1553312b-ed76-421c-a055-2579bdcf366c

Prescribing medicines in pregnancy database [Internet]. Therapeutic Goods Administration (TGA). 2018 [cited 15 March 2018]. Available from:

http://www.tga.gov.au/prescribing-medicines-pregnancy-database

[Internet]. Accessdata.fda.gov. 2018 [cited 15 March 2018]. Available from:

https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/008678s028lbl.pdf

[Internet]. Mhra.gov.uk. 2018 [cited 15 March 2018]. Available from:

http://www.mhra.gov.uk/home/groups/spcpil/documents/spcpil/con1513314904760.pdf

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Information on this page was last updated on 21 Mar 2018

Disclaimer

We’ve made all possible efforts to ensure that the information provided here is accurate, up-to-date and complete, however, it should not be treated as a substitute for professional medical advice, diagnosis or treatment. Practo only provides reference source for common information on medicines and does not guarantee its accuracy or exhaustiveness. The absence of a warning for any drug or combination thereof, should not be assumed to indicate that the drug or combination is safe, effective, or appropriate for any given patient. Practo does not assume any responsibility for any aspect of healthcare administered with the aid of information provided above. If you have any doubts about your medication then we strongly recommend that you consult with your doctor, nurse or healthcare provider. See detailed T&C here.