Ethionamide

Registered South African indications:

• Tuberculosis

Contraindications

• Hypersensitivity to the active ingredient or any of its excipients
• Severe hepatic impairment
• Previous hypersensitivity to ethionamide, isoniazid, pyrazinamide or niacin

Cautions

• Pregnancy
• Breastfeeding
• Severe renal impairment (CrCl<30ml/min)
• Mild to moderate hepatic impairment
• Depression
• Psychiatric illness
• Alcoholism
• Epilepsy
• Hypothyroidism
• Diabetes mellitus

Forms avail. in SA and covered in this monograph: tab

Drug resistant tuberculosis- intensive phase (in combination with other medication)

 Less than 33kg

• Oral (tab): 15-20mg/kg/day as single dose; Max: 1g/24hrs; Treatment duration: 6 months 

Between 33-50kg

• Oral (tab): 500mg, dly; Max: 1g/24hrs; Treatment duration: 6 months

Between 50-70kg

• Oral (tab): 750mg, dly; Max: 1g/24hrs; Treatment duration: 6 months

Greater than 70kg

• Oral (tab): 750-1000mg, dly; Max: 1g/24hrs; Treatment duration: 6 months

Drug resistant tuberculosis- continuation phase (in combination with other medication)

 Less than 33kg

• Oral (tab): 15-20mg/kg/day as single dose; Max: 1g/24hrs; Treatment duration: 18 months 

Between 33-50kg

• Oral (tab): 500mg, dly; Max: 1g/24hrs; Treatment duration: 18 months

Between 50-70kg

• Oral (tab): 750mg, dly; Max: 1g/24hrs; Treatment duration: 18 months

Greater than 70kg

• Oral (tab): 750-1000mg, dly; Max: 1g/24hrs; Treatment duration: 18 months

Paed. forms avail. in SA and covered in this monograph: tab

Drug sensivitive TB meningitis
Drug resistant pulmonary and extrapulmonary tuberculosis

Younger than 10 years

• Oral (tab): 10mg/kg/day, Titrate over 1 week to 15-20mg/kg, dly; Give as 2 divided doses until well tolerated; Max: 750mg/24hrs

Older than 10 years

• See adult dosage
  Refer to TB Guidelines

Decisions related to dose adjustment/discontinuing TB regimen must be discussed in advance with Pulmonologists/Infectious Disease specialists, and cases must be dealt with individually

Pregnancy

• Caution
• Ethionamide use during pregnancy is not recommended. Ethionamide has been found to cross the placenta and various birth defects have been associated with ethionamide use during pregnancy

Breastfeeding

• Caution
• Ethionamide excretion into breast milk is unknown. Caution is advised when breastfeeding women are taking ethionamide, monitoring of breastfeeding infant is recommended

Renal Impairment

• CrCl≥30ml/min: No adjustment recommended
• CrCl<30ml/min: Caution; dose adjustment recommended

Hepatic Impairment

• Mild to moderate: Caution; no dose adjustment recommended
• Severe: Contraindicated

Elderly

• No dose adjustment recommended

Porphyria Information

• Not yet classified (NC)

Drugs in Sport

• Permitted - No warnings

Central Nervous System Disorders

• Seizure
• Encephalopathy
• Anxiety
• Depression
• Acute psychosis
• Optic neuritis
• Peripheral neuropathy

Gastrointestinal Disorders

• Gastrointestinal disturbances
• Nausea and vomiting
• Loss of appetite
• Abdominal discomfort
• Diarrhoea
• Weight loss
• Excessive salivation
• Metallic taste

Hepatobiliary Disorders

• Hepatitis
• Jaundice
• Hepatotoxicity

Endocrine and Metabolic Disorders

• Hypothyroidism
• Gynecomastia
• Impotence
• Amenorrhoea
• Hypoglycaemia

Musculoskeletal Disorders

• Arthralgia

Skin and Subcutaneous Tissue Disorders

• Photosensitivity
• Alopecia

Immune, Blood and Lymphatic System Disorders

• Hypersensitivity reactions

• Cycloserine
• Terizidone
• Isoniazid

• Thyroid function  
• Liver function  

Ethionamide may be bacteriostatic or bactericidal in action, depending on the concentration of the drug attained at the site of infection and the susceptibility of the infecting organism. Ethionamide is a nicotinic acid derivative related to isoniazid. It is thought that ethionamide undergoes intracellular modification and acts in a similar fashion to isoniazid. Isoniazid inhibits the synthesis of mycolic acids, an essential component of the bacterial cell wall.

Tablet 250mg

• Ethatyl (Sanofi)
• Ethionamide Macleods 250mg (Macleods Pharmaceuticals)