Details

Isoniazid is an antibiotic that fights bacteria. Isoniazid is used to treat and to prevent tuberculosis (TB). You may need to take other TB medicines in combination with isoniazid. When treating active TB, isoniazid must be used with other TB medicines. Tuberculosis can become resistant to treatment if isoniazid is used alone. Serious and sometimes fatal liver problems may occur during treatment with isoniazid or after you stop taking this medicine, even months after stopping. The risk of liver problems is highest in adults between the ages of 35 and 65. To make sure isoniazid is safe for you, tell your doctor if you have a history of liver disease kidney disease nerve problems that cause pain, weakness, or numbness diabetes HIV or AIDS if you are 35 or older if you drink alcohol daily if you are malnourished if you use any medicines that are injected or if you have ever had to stop taking isoniazid for any reason.

Typical Uses

Isoniazid is used with other medications to treat active tuberculosis (TB) infections. It is also used alone to prevent active TB infections in people who may be infected with the bacteria (people with positive TB skin test). Isoniazid is an antibiotic and works by stopping the growth of bacteria. This antibiotic treats only bacterial infections. It will not work for viral infections (such as common cold, flu). Unnecessary use or misuse of any antibiotic can lead to its decreased effectiveness.

Side Effects

Common side effects of isoniazid include itching, tired feeling, weakness, fever for 3 days or longer upper stomach pain, loss of appetite or dark urine, clay-coloured stools, jaundice (yellowing of the skin or eyes) numbness, tingling, or burning pain in your hands or feet joint pain or nausea, vomiting, upset stomach.

Drug Interactions

• Isoniazid+citalopram- Talk to your doctor before using citalopram together with isoniazid. Combining these medications may increase the blood levels of citalopram and increase the risk of certain side effects, including an irregular heart rhythm that may be serious or life-threatening.
• Isoniazid+clopidogrel- Talk to your doctor before using clopidogrel together with isoniazid. Combining these medications may reduce the effects of clopidogrel in helping to prevent heart attacks or strokes. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications.
• Isoniazid+lomitapide- Isoniazid may increase the blood levels of lomitapide. You may be more likely to experience side effects such as diarrhoea, nausea, vomiting, stomach pain or discomfort, indigestion, gas, constipation, and liver damage. Talk to your doctor if you have any questions or concerns.
• Isoniazid+tizanidine- Using tizanidine together with isoniazid is generally not recommended. Combining these medications may significantly increase the blood levels and effects of tizanidine. This may cause blood pressure to fall excessively, especially when you rise from a sitting or lying position. The risk of other side effects such as drowsiness, dizziness, light-headedness, and fainting may also increase.

Mechanism of action

Isoniazid belongs to a class of anti-tuberculosis drugs. It suppresses the growth of tuberculosis causing bacteria (Mycobacterium tuberculosis). It interferes with the formation of the outer protective covering (cell wall) of the bacteria by inhibiting the synthesis of a chemical called mycolic acid an essential component of cell wall.

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