Isoniazid (INH) is one of the first-line drugs in the treatment of patients with mycobacterium tuberculosis. It is used in combination with other first and second-line drugs (e.g. rifampicin, ethambutol, pyrazinamide, and streptomycin).

Isoniazid uses:

• Active tuberculosis infections:

  • It is used to treat infections caused by Mycobacterium tuberculosis.

• Latent tuberculosis infection:

  • Can treat latent tuberculosis or used as a preventive therapy against Mycobacterium tuberculosis.

• Off Label Use of Isoniazid in Adults:

  • Nontuberculous infection can be treated e.g Mycobacterium kansasii.

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Isoniazid (INH) Dose in Adults:

Isoniazid (INH) Dose in the treatment of active drug-susceptible Tuberculosis: Oral, IM:

Note:

• Use along with other antitubercular agents.
• Use pyridoxin as a prophylactic drug against neuropathy.

• ATS/CDC/IDSA drug-susceptible tuberculosis guideline recommendations:

  • Dosing:

    • Once-daily therapy:
      • 5 mg/kg/dose (usual dose: 300 mg) once per day.
      • Note:
        • The frequency of dose is once per day during the intensive and continuation phases; however, 5 days per week administration by directly observed therapy (DOT) is an acceptable alternative.
    • Three-times-weekly DOT:
      • 15 mg/kg/dose (usual dose: 900 mg) administered 3 times weekly
    • Twice-weekly DOT:
      • 15 mg/kg/dose (usual dose: 900 mg) administered twice weekly
    • Once-weekly DOT:
      • 15 mg/kg/dose (usual dose: 900 mg) administered once weekly

  • Regimens:

    • Treatment regimens for pulmonary tuberculosis and tuberculous meningitis consist of an initial 2-month phase of a 4-drug regimen, followed by a continuation phase of an additional 4 to 7 months of isoniazid and rifampin for pulmonary tuberculosis and a continuation phase of an additional 7 to 10 months of isoniazid and rifampin for tuberculous meningitis (optimal duration is not defined although continuation phase must continue for a minimum of 7 additional months).
    • Adjunctive corticosteroid therapy (eg, dexamethasone, prednisolone) tapered over 6 to 8 weeks is also recommended for tuberculous meningitis.
    • Isoniazid frequency and dosing differ depending on the treatment regimen selected.

Isoniazid (INH) Dose in the treatment of Tuberculosis, latent infection: Oral, IM:

Note:

• Pyridoxine is recommended along with this in malnourished patients, pregnant or breastfeeding women, or those prone to neuropathy (eg, patients with HIV-infection, diabetes, or chronic alcohol abusers).

• Isoniazid monotherapy:

  • Non-HIV infected:
    • 5 mg/kg (maximum: 300 mg per dose) once daily for 6 or 9 months or 15 mg/kg (maximum: 900 mg per dose) twice weekly for 6 or 9 months.
    • Note:
      • 9 months is optimal; 6 months may be considered to reduce costs of therapy and improve adherence.
  • HIV-infected patients who are receiving antiretroviral therapy:
    • 300 mg once daily or 900 mg twice weekly for 9 months;
    • a longer duration is recommended for HIV-infected patients in high-incidence settings.
    • Note:
      • LTBI treatment is recommended in HIV-infected patients testing positive for LTBI (but have no evidence of TB disease and no history of treatment for active or LTBI) or in HIV-infected close contacts of anyone who has infectious TB (regardless of screening tests for LTBI).

• Isoniazid and rifapentine combination regimen:

  • Once-weekly regimen:
    • 15 mg/kg/dose (maximum: 900 mg/dose) once weekly in combination with rifapentine for 12 weeks by directly observed therapy (DOT) or self-administered therapy.
    • Note:
      • The once-weekly rifapentine-containing regimen may only be used in patients who are not pregnant and/or not expecting to become pregnant;
      • If used in HIV-infected patients, it may only be used in those receiving antiretroviral therapy (ART) with acceptable drug-drug interactions with rifapentine.
  • Once-daily regimen (HIV-infected patients):
    • 300 mg once daily in combination with rifapentine for 1 month.
    • Note:
      • This regimen has been studied in HIV-infected patients living in regions with high tuberculosis prevalence or with evidence of latent tuberculosis infection but is not yet widely recommended.

Isoniazid (INH) Dose in the treatment of Nontuberculous mycobacterium (M. kansasii) (off-label):

• 5 mg/kg/day (maximum: 300 mg daily) for a duration to include 12 months of culture-negative sputum;
• It is typically used in combination with ethambutol and rifampin.

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Isoniazid (INH) Dose in Childrens:

Note:

• Recommendations often change due to epidemiology (resistance) and emerging information;
• Consult the CDC and WHO for current recommendations, as appropriate.
• For patients at risk for isoniazid-induced neuropathy, concomitant pyridoxine is recommended;
• Risk factors for developing neuropathy include pregnancy, breastfeeding infants, and persons with any of the following:
  • HIV,
  • diabetes,
  • malnutrition,
  • alcoholism,
  • chronic renal failure, or
  • advanced age.

Isoniazid (INH) Dose in the treatment of active drug-susceptible TB infection (excluding meningitis):

Note:

• Always use as part of a multidrug regimen.
• Any regimens using less than once-daily dosing should administer dosing as directly observed therapy (DOT).
• Treatment regimens for pulmonary tuberculosis consist of an initial 2-month intensive phase of a 4-drug regimen, followed by a continuation phase of an additional 4 to 7 months of isoniazid and rifampin.
• Isoniazid frequency and dosing differ depending on the treatment regimen selected; consult current drug-sensitive TB guidelines for detailed information.

• ATS/CDC/IDSA Recommendations:

  • Once-daily or 5 times weekly (DOT):

    • Infants, Children, and Adolescents <15 years, weighing ≤40 kg:
      • Oral, IM: 10 to 15 mg/kg/dose once daily;
      • The maximum dose: 300 mg/dose
    • Children and Adolescents <15 years weighing >40 kg or Adolescents ≥15 years:
      • Oral, IM: 5 mg/kg/dose once daily (typical dose: 300 mg)

  • Three-times-weekly DOT:

Note:

• Although suggested dosing based on experience with twice-weekly regimen;
• Experts suggest three-times-weekly regimens are more effective than twice-weekly DOT regimens;
• Three-times-weekly DOT may be used as part of an intensive phase and/or continuation phase dosing regimen.
  • • Infants, Children, and Adolescents <15 years, weighing ≤40 kg:
      • Oral, IM: 20 to 30 mg/kg/dose three times weekly;
      • The maximum dose: 900 mg/dose;
      • In adolescents, some experts would use 15 mg/kg/dose three times weekly;
      • The maximum dose: 900 mg/dose
    • Children and Adolescents <15 years weighing >40 kg or Adolescents ≥15 years:
      • Oral, IM: 15 mg/kg/dose three times weekly (typical dose: 900 mg)

  • Twice-weekly DOT:

Note:

• Regimen not generally recommended;
• Do not use in HIV patients or those with smear-positive and/or cavitary disease.
• This therapy should only be used following completion of a 2-week intensive phase once-daily (or 5-times weekly) regimen.
• Missed doses result in the equivalent of once-weekly dosing which has been shown to be inferior and is associated with treatment failure, relapse, and development of drug resistance.
  • Infants, Children, and Adolescents <15 years, weighing ≤40 kg:
    • Oral, IM: 20 to 30 mg/kg/dose twice weekly;
    • The maximum dose: 900 mg/dose
  • Children and Adolescents <15 years weighing >40 kg or Adolescents ≥15 years:
    • Oral, IM: 15 mg/kg/dose twice-weekly (typical dose: 900 mg)

Isoniazid (INH) Dose in the treatment of Latent TB infection (LTBI):

• Isoniazid combination therapy:
• Note:
  • Should not be used in individuals presumed to be infected with isoniazid or rifampin-resistant strains of TB.
  • Isoniazid combination therapy with rifapentine is the CDC preferred regimen for LTBI.
• Rifapentine combination (preferred): Regardless of HIV status:
• Note:
  • It may be administered by DOT or self-administered therapy (SAT) at the clinician's discretion based on local practice, patient attributes/preferences, and other factors including risk for TB disease progression.
  • Rifapentine combination is preferred in persons with HIV, including AIDS, and taking antiretroviral therapy (ART) with acceptable drug-drug interactions when guided by experienced clinicians.
  • Children 2 to 11 years, weighing at least 10 kg:
    • Oral: 25 mg/kg/dose once weekly of isoniazid for 12 weeks (12 doses);
    • The maximum dose: 900 mg/dose.
  • Children ≥12 years and Adolescents:
    • Oral: 15 mg/kg/dose once weekly of isoniazid for 12 weeks (12 doses), round dose up to nearest 50 or 100 mg;
    • The maximum dose: 900 mg/dose.

• Rifampin combination: HIV-exposed/-positive:

  • Children:
    • Oral: 10 to 15 mg/kg/dose once daily;
    • The maximum dose: 300 mg/dose;
    • The treatment duration is 3 to 4 months.

• Isoniazid monotherapy:

Note: Intermittent regimens (once or twice weekly) should be administered by DOT.

• Infants and Children:

  • Non-HIV-exposed/-positive:
    • Oral: 10 to 20 mg/kg/dose once daily;
    • maximum dose: 300 mg/dose OR 20 to 40 mg/kg/dose twice weekly as DOT;
    • maximum dose: 900 mg/dose;
    • The treatment duration: 9 months (270 daily doses or 76 twice-weekly doses).
  • HIV-exposed/-positive:
    • Oral: 10 to 15 mg/kg/dose once per day (maximum dose: 300 mg/dose) OR
    • 20 to 40 mg/kg/dose (maximum dose: 900 mg/dose) two times every week,as DOT;
    • The treatment duration is 9 months.

• Adolescents:

  • Non-HIV-exposed/-positive:
    • Oral: 10 to 20 mg/kg/dose once daily;
    • The maximum dose: 300 mg/dose or 20 to 40 mg/kg/dose twice weekly as DOT;
    • The maximum dose: 900 mg/dose;
    • Treatment duration: 9 months (270 daily doses or 76 twice-weekly doses).
  • HIV-exposed/-positive:
    • Oral: 300 mg once daily or 900 mg twice weekly as DOT;
    • Treatment duration: 9 months.

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Isoniazid Pregnancy Risk Category: C

• Isoniazid can pass the placental barrier
• Treatment is advised when there is a high risk of developing tuberculosis in the fetus.
• It is recommended that it be used as part of the initial treatment.
• Close monitoring during pregnancy and after delivery is advised due to an increased risk of developing hepatitis.
• This is indicated for pregnant women infected with HIV-coinfection.
• Pyridoxine is recommended to decrease the risk of neuropathy.
• Pregnant women could be more susceptible to tuberculosis infection due to biological changes that occur during pregnancy or early postpartum.

Isoniazid use during breastfeeding:

• Breast milk contains the acetyl–isoniazid metabolite and isoniazid.
• When using the highest concentration of breast milk, the relative infant dose (RID), of isoniazid ranges from 12% to 25%.
• This is in comparison to an infant therapeutic dose between 10 and 20 mg/kg/day.
• If the RID of the medication is less than 10%, breastfeeding is acceptable. However, if it is greater than 25%, breastfeeding should be avoided.
• The RID of isoniazid was calculated based on a milk concentration of 16.6 mg/mL. This gives an estimated daily infant dose via breastmilk of 2.49 mg/kg/day.
• The milk concentration was determined after a single maternal dose of oral isoniazid 300mg.
• The peak concentrations of isoniazid in breast milk and the metabolite peaked 1 and 3 hours respectively after the dose.
• In another study, nine women were treated with chronic isoniazid 300 mg/day.
• Breast milk was tested for lower and more variable peak concentrations (1 hour after the dose).
• Breastfed infants can also detect isoniazid in their urine after high maternal doses (10 mg/kg).
• Based on the available data, these concentrations are nontoxic and not therapeutic to treat active tuberculosis or latent tuberculosis.
• Nursing mothers are not considered to be in any way contraindicated.
• The use of isoniazid in the treatment of drug-susceptible tuberculosis is not contraindicated.
• It is safe to breastfeed patients who have been treated with isoniazid.
• Breastfeeding infants should be checked for jaundice.
• If jaundice occurs, discontinue breastfeeding and/or switch to a different medication.
• For both mother and baby, pyridoxine supplementation should be considered.
• One review recommends that infants who have been given isoniazid should be administered the maternal dose within 30 minutes of the last feed.
• Patients with HIV or active infections should not breastfeed.
• Breastfeeding mothers who have tuberculosis may continue to breastfeed using the unaffected breast.

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INH Dose in Kidney Disease:

No dosage adjustment is necessary.

• Hemodialysis:
  • No dosage adjustment needed if the patient is on dialysis, administer after hemodialysis on dialysis days.

Dose in Liver disease:

• No dosage adjustments are provided but use with caution as it may cause additional liver damage in patients with preexisting liver disease.
• It is absolutely contraindicated in patients with acute liver disease or previous isoniazid-associated hepatic injury.
• For ALT or AST >3 times the ULN:
  • discontinue or temporarily withhold treatment.
  • Treatment with isoniazid for latent tuberculosis infection should be deferred in patients with acute hepatic diseases.

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Side Effects of Isoniazid (INH):

• Hepatic:

  • Increased serum transaminases
  • Hepatitis
  • Hyperbilirubinemia
  • Jaundice

• Cardiovascular:

  • Vasculitis

• Central Nervous System:

  • Brain Disease
  • Memory Impairment
  • Paresthesia
  • Peripheral Neuropathy
  • Psychosis
  • Seizure

• Dermatologic:

  • Skin Rash
    • Morbilliform
    • Maculopapular
    • Pruritic
    • Or Exfoliative
  • Toxic Epidermal Necrolysis

• Endocrine & Metabolic:

  • Gynecomastia
  • Hyperglycemia
  • Metabolic Acidosis
  • Pellagra
  • Pyridoxine Deficiency

• Gastrointestinal:

  • Epigastric Distress
  • Nausea
  • Pancreatitis
  • Vomiting

• Genitourinary:

  • Bilirubinuria

• Hematologic & Oncologic:

  • Agranulocytosis
  • Anemia
    • Sideroblastic
    • Hemolytic
    • Or Aplastic
  • Eosinophilia
  • Lymphadenopathy
  • Thrombocytopenia

• Immunologic:

  • DRESS Syndrome

• Neuromuscular & Skeletal:

  • Lupus-Like Syndrome
  • Rheumatic Disease

• Ophthalmic:

  • Optic Atrophy
  • Optic Neuritis

• Miscellaneous:

  • Fever

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Contraindications to Isoniazid (INH):

• Hypersensitivity to any component of isoniazid, including drug-induced liver disease and acute liver disease; history of hepatic injury while receiving isoniazid therapy.
• Previous severe adverse reactions (drug fevers, chills, arthritis) to isoniazid

Warnings and precautions

• Hepatitis: [US-Boxed Warning]

  • Severe, sometimes fatal, hepatitis can occur. It usually develops within the first three months of treatment.
  • However it may also develop after several months of continued treatment.
  • Hepatitis risk may be increased by alcohol intake, chronic liver disease, and injection drug use.
  • Careful monitoring is required for patients who are given isoniazid.
  • Fatal liver disease associated with isoniazid could be more common in women, particularly in black and Hispanic women and any woman who has had a baby in the last six months.
  • These groups may allow for closer monitoring.
  • Patients over 35 years old should have their AST and ALT checked at baseline and every other month.
  • Any symptoms that may indicate hepatitis must be reported to the doctor.
  • If any of these symptoms are present, counsel the patient to immediately stop therapy and contact their doctor.
  • Consider discontinuing isoniazid if liver dysfunction exceeds 3 to 5 times the upper limit for normal (ULN).
  • If you feel that isoniazid needs to be reinstituted for treatment, wait until symptoms and laboratory abnormalities are resolved.
  • Then, start slowly increasing the doses and withdrawing immediately if there is evidence of recurrent liver disease.

• Peripheral neuropathies:

  • Individuals at high risk of developing peripheral neuropathies such as HIV infection, nutritional deficiencies, diabetes, obesity, chronic renal failure, and advanced age should take pyridoxine supplements.

• Hepatic impairment

  • Patients with hepatic impairment should be cautious; contraindicated for patients with acute liver disease and previous isoniazid-associated injury.
  • Patients with acute hepatic disease should delay treatment with isoniazid (LTBI) for latent tuberculosis.

• Renal impairment

  • Patients with severe renal impairment require dose adjustment

Isoniazid: Drug Interaction

Risk Factor C (Monitor therapy)
Acetaminophen	Isoniazid may enhance the adverse/toxic effect of Acetaminophen.
ARIPiprazole	CYP3A4 Inhibitors (Weak) may increase the serum concentration of ARIPiprazole. Management: Monitor for increased aripiprazole pharmacologic effects. Aripiprazole dose adjustments may or may not be required based on concomitant therapy and/or indication. Consult full interaction monograph for specific recommendations.
BCG Vaccine (Immunization)	Antibiotics may diminish the therapeutic effect of BCG Vaccine (Immunization).
CarBAMazepine	May enhance the hepatotoxic effect of Isoniazid. Isoniazid may increase the serum concentration of CarBAMazepine.
Chlorzoxazone	Isoniazid may increase the serum concentration of Chlorzoxazone. Isoniazid may decrease the serum concentration of Chlorzoxazone. Specifically, it may decrease chlorzoxazone concentrations below baseline after isoniazid discontinuation.
Corticosteroids (Systemic)	May decrease the serum concentration of Isoniazid.
CycloSERINE	Isoniazid may enhance the adverse/toxic effect of CycloSERINE. Specifically, CNS toxicity may be enhanced.
CYP2E1 Substrates (High risk with Inhibitors)	Isoniazid may decrease the serum concentration of CYP2E1 Substrates (High risk with Inhibitors). Specifically, it may decrease CYP2E1 substrate serum concentrations below baseline after isoniazid discontinuation. Isoniazid may increase the serum concentration of CYP2E1 Substrates (High risk with Inhibitors).
Disulfiram	May enhance the adverse/toxic effect of Isoniazid. Disulfiram may increase the serum concentration of Isoniazid.
Dofetilide	CYP3A4 Inhibitors (Weak) may increase the serum concentration of Dofetilide.
Ethionamide	May increase the serum concentration of Isoniazid.
Flibanserin	CYP3A4 Inhibitors (Weak) may increase the serum concentration of Flibanserin.
Itraconazole	Isoniazid may decrease the serum concentration of Itraconazole.
Ketoconazole (Systemic)	Isoniazid may decrease the serum concentration of Ketoconazole (Systemic).
Lactobacillus and Estriol	Antibiotics may diminish the therapeutic effect of Lactobacillus and Estriol.
Levodopa-Containing Products	Isoniazid may diminish the therapeutic effect of LevodopaContaining Products.
NiMODipine	CYP3A4 Inhibitors (Weak) may increase the serum concentration of NiMODipine.
Propacetamol	Isoniazid may enhance the hepatotoxic effect of Propacetamol.
Rifamycin Derivatives	May enhance the hepatotoxic effect of Isoniazid. Even so, this is a frequently employed combination regimen.
Safinamide	May enhance the adverse/toxic effect of Isoniazid. Specifically, there is an increased risk for hypertension.
Theophylline Derivatives	Isoniazid may increase the serum concentration of Theophylline Derivatives. Exceptions: Dyphylline.
Risk Factor D (Consider therapy modification)
Fosphenytoin	Isoniazid may increase the serum concentration of Fosphenytoin. Management: Consider alternatives. If concomitant therapy cannot be avoided, monitor for increased phenytoin concentrations/effects with isoniazid initiation/dose increase, or decreased concentrations/effects with isoniazid discontinuation/dose decrease.
Lemborexant	CYP3A4 Inhibitors (Weak) may increase the serum concentration of Lemborexant. Management: The maximum recommended dosage of lemborexant is 5 mg, no more than once per night, when coadministered with weak CYP3A4 inhibitors.
Lomitapide	CYP3A4 Inhibitors (Weak) may increase the serum concentration of Lomitapide. Management: Patients on lomitapide 5 mg/day may continue that dose. Patients taking lomitapide 10 mg/day or more should decrease the lomitapide dose by half. The lomitapide dose may then be titrated up to a max adult dose of 30 mg/day.
Phenytoin	Isoniazid may increase the serum concentration of Phenytoin. Management: Consider alternatives. If concomitant therapy cannot be avoided, monitor for increased phenytoin concentrations/effects with isoniazid initiation/dose increase, or decreased concentrations/effects with isoniazid discontinuation/dose decrease.
Prothionamide	Isoniazid may increase the serum concentration of Prothionamide. Prothionamide may increase the serum concentration of Isoniazid. Management: Consider a prothionamide dose reduction and do not exceed 500 mg per day if combined with isoniazid. Additionally, monitor for increased isoniazid toxicities and ensure pyridoxine supplementation is provided if these drugs are combined.
Sodium Picosulfate	Antibiotics may diminish the therapeutic effect of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic.
Triazolam	CYP3A4 Inhibitors (Weak) may increase the serum concentration of Triazolam. Management: Consider triazolam dose reduction in patients receiving concomitant weak CYP3A4 inhibitors.
Typhoid Vaccine	Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Management: Vaccination with live attenuated typhoid vaccine (Ty21a) should be avoided in patients being treated with systemic antibacterial agents. Use of this vaccine should be postponed until at least 3 days after cessation of antibacterial agents.
Ubrogepant	CYP3A4 Inhibitors (Weak) may increase the serum concentration of Ubrogepant. Management: In patients taking weak CYP3A4 inhibitors, the initial and second dose (if needed) of ubrogepant should be limited to 50 mg.
Risk Factor X (Avoid combination)
BCG (Intravesical)	Antibiotics may diminish the therapeutic effect of BCG (Intravesical).
Cholera Vaccine	Antibiotics may diminish the therapeutic effect of Cholera Vaccine. Management: Avoid cholera vaccine in patients receiving systemic antibiotics, and within 14 days following the use of oral or parenteral antibiotics.
Pimozide	CYP3A4 Inhibitors (Weak) may increase the serum concentration of Pimozide.

 

Monitoring parameters:

Baseline and periodic (more frequently in patients with a higher risk for hepatitis) liver function tests (ALT and AST); Sputum cultures monthly (until 2 consecutive negative cultures reported); Monitoring for prodromal signs of hepatitis.

Latent tuberculosis infection (LTBI) therapy:

American Thoracic Society/Centers for Disease Control (ATS/CDC) recommendations:

• Monthly clinical evaluation, including a brief physical exam for adverse events.
• Use should be carefully monitored in the following groups:
  • daily users of alcohol,
  • active chronic liver disease,
  • severe renal dysfunction,
  • age >35 years,
  • concurrent use of any chronically administered drug,
  • history of previous isoniazid discontinuation,
  • existence of or conditions predisposing to peripheral neuropathy,
  • pregnancy,
  • injection drug use,
  • women in minority groups (particularly postpartum),
  • HIV seropositive patients.
• AST and ALT should be obtained at baseline and at least monthly during LTBI use.
• Discontinue temporarily or permanently if liver function tests >3 to 5 times ULN.
• Routine, periodic monitoring is recommended for any patient with an abnormal baseline or at increased risk for hepatotoxicity.

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How to administer Isoniazid?

• Oral:
  • Do not administer with food (bioavailability is decreased).
• Intramuscular:
  • IM injection may be used for patients who are unable to either take or absorb oral therapy. Inject deep IM into a large muscle mass.

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Mechanism of action of Isoniazid (INH):

• Isoniazid blocks the production of mycolic acid, which is an essential component in the bacterial cell walls. 
• Isoniazid can be used to kill Mycobacterium tuberculosis organisms that are actively growing in intracellular and extracellular environments at therapeutic levels.

Notice:

• It is metabolized through acetylation or dehydrazination.
• Genetic factors determine the rate at which acetylation occurs. Blacks and whites make up approximately half of the "slow inactivators", while the rest are called "rapid activators".
• Most Eskimo and Asian patients can be described as "rapid activators". 
• Although acetylation rate doesn't affect effectiveness in any way, slow acetylation can lead to increased blood levels and possible adverse effects.

Absorption: Oral, IM:

• Rapid and complete;
• Its absorption rate is reduced if administer along with food

Distribution:

• It distributes in all over body fluids and tissues including CSF

Protein binding:

• 10% to 15%

Metabolism:

• Hepatic to acetyl-isoniazid with decay rate determined genetically by acetylation phenotype;
• It undergoes further hydrolysis to isonicotinic acid and acetyl-hydrazine

Half-life:

• May be prolonged in patients with hepatic or renal function impairment.
  • Fast acetylators: 30 to 100 minutes
  • Slow acetylators: 2 to 5 hours

Time to peak, serum:

• 1 to 2 hours

Excretion:

• Urine (75% to 95% as unchanged drug and metabolites);
• also excreted in feces and saliva in a small amount

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International Brand Names of Isoniazid:

• DOM-Isoniazid
• Isotamine
• PDP-Isoniazid
• Antimic
• Bitub
• Cemidon
• Curazid Forte
• Dianicotyl
• Eutizon
• Fluodrazin
• Hidrazida
• Hydra
• Hydrazin
• N.H.
• INH Agepha
• INH Lannacher
• INH Waldheim
• Iscotin
• Iso
• Isocid
• Isokin
• Isonex
• Isoniac
• Isoniazid
• Isoniazid Atlantic
• Isoniazid ”Dak”
• Isoniazid ”Oba”
• Isoniazide Drank FNA
• Isoniazidum
• Isonicid
• Isonid
• Isozid
• Isozide
• Nicizina
• Nicotibine
• Nicozid
• Nidrazid
• Nisozid
• Nydrazide
• Pycazide
• Rimicid
• Rimifon
• Sheng Jun
• Solonex
• B.Zide
• Tebilon
• Tibinide
• Tubilysin
• Valifol
• Yuhan-Zid

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Isoniazid Brand Names in Pakistan:

Isoniazid Syrup 50 Mg in Pakistan
Stand-Inh	Standard Drug Co.

 

Isoniazid Syrup 50 Mg/5ml in Pakistan
Isozide Syrup	Nabiqasim Industries (Pvt) Ltd.
Nydrazide	Wilshire Laboratories (Pvt) Ltd.
Polyzide	Polyfine Chempharma (Pvt) Ltd.
Sonorex	Rex Pharmaceuticals Pakistan

 

Isoniazid Tablets 50 Mg in Pakistan
Isoniazid	Unexo Labs (Pvt) Ltd.
Isoniazide	Jawa Pharmaceuticals(Pvt) Ltd.

 

Isoniazid Tablets 100 Mg in Pakistan
Fairzide	Ferro Pharmaceutical Laboratories
I.N.H	Lisko Pakistan (Pvt) Ltd
I.N.H	Irza Pharma (Pvt) Ltd.
I.N.H.	P.D.H. Pharmaceuticals (Pvt) Ltd.
Isoniazid	Unexo Labs (Pvt) Ltd.
Isoniazid	Lahore Chemical & Pharmaceutical Works (Pvt) Ltd
Isoniazid	Geofman Pharmaceuticals
Isoniazid	Genera Pharmaceuticals
Isoniazid	Lahore Chemical & Pharmaceutical Works (Pvt) Ltd
Isoniazid	Lahore Chemical & Pharmaceutical Works (Pvt) Ltd
Isoniazide	Jawa Pharmaceuticals(Pvt) Ltd.
Isozide Tablet	Amson Vaccines & Pharma (Pvt) Ltd.
Niazid	Pharmawise Labs. (Pvt) Ltd.
Niazid	Pharmawise Labs. (Pvt) Ltd.
Nydrazide	Wilshire Laboratories (Pvt) Ltd.
Pharozide	Pharmacare Laboratories (Pvt) Ltd.
Remoniazid	Syntex Pharmaceuticals
Sonorex	Rex Pharmaceuticals Pakistan

 

Isoniazid Tablets 300 Mg in Pakistan
I.N.H	Lisko Pakistan (Pvt) Ltd
Isozide Tablet	Amson Vaccines & Pharma (Pvt) Ltd.
Isozide Tablet	Amson Vaccines & Pharma (Pvt) Ltd.

 

Isoniazid Tablets 400 Mg in Pakistan
Isoniazid	Unexo Labs (Pvt) Ltd.