ethambutol + isoniazid + rifampicin

The combination of ethambutol, isoniazid, and rifampicin is a fixed-dose medication primarily used for treating tuberculosis (TB). This combination is part of the standard treatment regimen for TB, often used in the continuation phase of treatment after the initial intensive phase.

Drug Information

This medication works through multiple mechanisms to combat Mycobacterium tuberculosis. Rifampicin inhibits bacterial RNA polymerase, isoniazid interferes with mycolic acid synthesis in the bacterial cell wall, and ethambutol disrupts arabinogalactan synthesis in the cell wall.

The combination is typically administered orally, with dosing based on patient weight and treatment phase. It's usually taken on an empty stomach, one hour before or two hours after meals for optimal absorption.

Brand Names and Formulations

Several brand names exist for this combination, including:

• Akurit-3 (by Lupin Ltd)
• R-Cinex E (by Lupin Ltd)
• Rhe-FD (by Macleods Pharmaceuticals)
• Rhe-Kit (by Macleods Pharmaceuticals)
• Trac 3 (by Macleods Pharmaceuticals)
• Mycocox E (by Cadila Pharmaceuticals)
• Monto 3 (by Shreya Life Sciences)
• SCC 3 (by Maneesh Pharmaceuticals)

Side Effects

Common side effects include:

• Gastrointestinal issues: nausea, vomiting
• Skin reactions: rash, pruritus, urticaria
• Metabolic effects: elevated liver enzymes, increased uric acid levels
• Neurological effects: peripheral neuropathy (tingling and numbness in hands and feet)
• Visual disturbances (associated with ethambutol)
• Orange/red discoloration of bodily fluids including urine, sweat, tears, and saliva
• Fever and menstrual disturbances

Drug Interactions

This combination has numerous significant drug interactions:

• Anticonvulsants: phenobarbital, phenytoin, valproic acid, lamotrigine
• Anticoagulants: apixaban, betrixaban
• Hormonal contraceptives (reduced effectiveness)
• Immunosuppressants
• HIV medications
• Many other medications metabolized by liver enzymes

Due to rifampicin's strong enzyme-inducing properties, alternative birth control methods are recommended for women taking hormonal contraceptives.

Special Considerations

• Liver function should be monitored during treatment
• Not recommended for patients with severe liver or kidney problems
• Pyridoxine (vitamin B6) supplementation may be recommended to reduce the risk of peripheral neuropathy from isoniazid
• Patients should be monitored for visual changes due to ethambutol
• Alcohol should be avoided during treatment
• The medication may interfere with certain laboratory tests