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Rifampicin with isoniazid tablets

Updated 2 Feb 2023 | Isoniazid Rifamycins


Oral formulations of rifampicin and isoniazid.

Drugs List

  • rifampicin 150mg and isoniazid 100mg tablets
  • rifampicin 300mg and isoniazid 150mg tablets
  • RIFINAH 150mg+100mg tablets
  • RIFINAH 300mg+150mg tablets
  • Therapeutic Indications


    Tuberculosis: continuation phase treatment
    Tuberculosis: initial phase treatment in combination with other drugs


    Rifampicin and isoniazid must be used in combination with other anti-tuberculous drugs during the initial phase of treatment until the susceptibility of the infecting organism to rifampicin and isoniazid has been confirmed.


    Patients more than 50kg body weight
    Two 300mg+150mg tablets to be taken once daily (total daily dose 600mg rifampicin/300mg isoniazid).

    Patients less than 50kg body weight
    Three 150mg+100mg tablets to be taken once daily (total daily dose 450mg rifampicin/300mg isoniazid).


    (See Dosage; Adults).

    However, elderly patients should be treated with caution, especially if hepatic impairment is present.


    Combination of rifampicin and isoniazid is not recommended for use in children as dose adjustment is not readily achievable.

    However the individual components may be used independently (see relevant product information).


    Hereditary fructose intolerance

    Precautions and Warnings

    Predisposition to seizures
    Chronic renal failure
    Diabetes mellitus
    Epileptic disorder
    Glucose-galactose malabsorption syndrome
    Hepatic impairment
    History of psychosis
    Immunodeficiency syndromes
    Peripheral neuropathy
    Positive HIV status
    Slow acetylator status

    Consider vitamin K supplementation risk of vitamin K dependent coagulopathy
    Intermittent therapy increases the risk of hypersensitivity reactions
    Treatment to be initiated and supervised by a specialist
    Preparation contains sucrose
    Monitor hepatic function before treatment and regularly during treatment
    Monitor platelets before starting and during treatment
    Monitor renal function prior to initiating treatment
    Monitor hepatic function frequently in patients with hepatic impairment
    Perform blood counts in patients with alcohol dependence
    Perform blood counts in patients with hepatic impairment
    Perform blood counts on prolonged use of this treatment
    Adverse effects may be seen after ingestion of high-tyramine foods/drinks
    Advise patient that red discolouration of body fluids may occur
    Advise patients to report signs of hepatic damage (malaise, jaundice etc.)
    Discontinue if hepatitis develops
    Discontinue if thrombocytopenia occurs
    May cause convulsions
    May cause hyperbilirubinaemia
    May cause vitamin K dependent coagulopathy and severe bleeding
    Discontinue if haemolytic anaemia occurs
    Discontinue if renal failure develops
    Discontinue if significant/persistent hepatic function abnormalities occur
    Female: Barrier or non-hormonal contraception advised during treatment
    Advise patient of importance of full compliance
    Discolours soft contact lenses

    Patients should be seen monthly during therapy and should be questioned regarding symptoms associated with adverse effects. All abnormalities should be investigated including laboratory testing when necessary.

    Monitor transaminase monthly in patients over 35 years on a monthly basis, there is an increased risk of isoniazid-associated hepatitis in this patient population.

    The following factors are also associated with an increased risk of hepatitis; daily intake of alcohol, chronic liver disease, intravenous drug use, black or hispanic women.

    Rifampicin should be used with caution and under strict medical supervision in patients with hepatic impairment. Hepatic function should be monitored (especially serum alanine aminotransferase (ALT) and serum aspartate transaminase (AST)) before therapy and every two to four weeks during therapy.

    Pregnancy and Lactation


    Use rifampicin with isoniazid with caution in pregnancy.

    Animal studies have reported spina bifida in mice and rats and cleft palates in mice when administered rifampicin. Teratogenicity has been reported in rats. Rifampicin crosses the human placenta to the foetus. No controlled studies link the use of rifampicin to congenital defects in humans. One report described a 4.4% incidence of malformations, which is similar to the expected frequency of defects in the healthy population, but higher than the rate noted for other tuberculosis patients (Briggs, 2011).

    Several reviews have concluded that rifampicin was not a proven teratogen and recommended the use of rifampicin with isoniazid and ethambutol if necessary. Schaefer (2007) concludes that rifampicin is a drug of choice for the treatment of tuberculosis during pregnancy, Schaefer (2007) also suggests the use of rifampicin as prophylaxis against meningococcal infection. When administered during the last few weeks of pregnancy, post-natal haemorrhage in the mother and neonate may occur and therapy with vitamin K1 may be required.

    Animal studies in mice, rats and rabbits have not revealed teratogenic effects, but embryocidal effects were observed in rats and rabbits. Isoniazid crosses the human placenta to the foetus. Briggs (2011) concludes that isoniazid does not appear to be a human teratogen. Schaefer (2007) states isoniazid as the drug of choice for prophylaxis and treatment of tuberculosis in pregnancy and recommends combination with pyridoxine (vitamin B6) and monthly liver function tests. The American Thoracic Society recommends the use of the drug for tuberculosis during pregnancy as "Untreated tuberculosis represents a far greater hazard to a pregnant woman and her foetus than does treatment of the disease."

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Use rifampicin with isoniazid with caution in breastfeeding.

    The Centres for Disease Control and prevention state that breastfeeding should not be discouraged in patients taking pyrazinamide, rifampicin or isoniazid. Low levels of all three drugs are excreted in breast milk, the concentrations of these drugs is not considered sufficient for treatment of tuberculosis in the breastfed infant.

    Schaefer (2007) concludes that isoniazid (in combination with 0.5 to 1 mg of vitamin B6 prophylaxis per day for the infant), rifampicin and pyrazinamide are the tuberculostatics of choice during breastfeeding.

    Infant should be monitored for toxicity including hepatitis and vision changes. Observe for fatigue, weakness, malaise, anorexia, nausea and vomiting.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Side Effects

    Abdominal discomfort
    Acute interstitial nephritis
    Acute renal failure
    Acute tubular necrosis
    Adrenal suppression
    Aggravation of porphyria
    Bone pain
    Cerebral haemorrhage
    Dry mouth
    Erythema multiforme
    Exfoliative dermatitis
    Haemolytic anaemia
    Hepatic impairment
    Hypersensitivity reactions
    Increase in antinuclear antibodies (ANA)
    Influenza-like syndrome
    Intravascular coagulation (disseminated)
    Lyell's syndrome
    Menstrual disturbances
    Micturition disorders
    Muscle weakness
    Optic neuritis
    Pemphigoid reaction
    Possible staining of soft contact lenses
    Pseudomembranous colitis
    Reddish discolouration of body fluids
    Reflex disorders
    Renal impairment
    Respiratory symptoms
    Shortness of breath
    Skin reactions
    Stevens-Johnson syndrome
    Superficial tooth discolouration
    Systemic lupus erythematosus-like syndrome
    Toxic epidermal necrolysis


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: May 2015

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Martindale: The Complete Drug Reference (online) London: Brayfield A (ed). Pharmaceutical Press Accessed on 21 May 2015.

    Medications and Mothers' Milk, Sixteenth Edition (2014) Hale, T and Rowe, H, Hale Publishing, Plano, Texas.

    Summary of Product Characteristics: Rifinah 150mg/100mg. Sanofi-Aventis. Revised March 2019.
    Summary of Product Characteristics: Rifinah 150mg/300mg. Sanofi-Aventis. Revised March 2019.

    NICE Evidence Services Available at: Last accessed: 13 September 2017

    The Norwegian Porphyria Centre (NAPOS).
    Available at:
    Last revised: 01 October 2004
    Last accessed: 21 May 2015

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Rifampin Last revised: 7 September, 2013
    Last accessed: 21 May, 2015

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Isoniazid Last revised: 7 September, 2013
    Last accessed: 21 May, 2015

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