Guide To Isoniazid

Isoniazid is an oral antibiotic. Depending on the condition for which it is being used, patients may need to take isoniazid for months. During treatment, monthly liver function tests are needed. In addition, patients may need to take vitamin B6 supplements. Patients should take the entire course their doctor has prescribed to prevent antibiotic resistance.

This antibiotic is a common bacterial infection treatment. Of course, it is most often prescribed as a tuberculosis treatment. It can be prescribed alongside other oral antibiotics for some cases. It does not come as an antibiotic cream or ointment. Finally, patients must understand how it works before taking it.

How It Works 


As an antibiotic, isoniazid fights bacteria. Specifically, it stops the mycobacterial cell wall from forming. This prodrug is activated by a bacterial enzyme called KatG, and it kills rapidly dividing mycobacteria. This antibiotic is bacteriostatic for bacteria that are slow to grow. It blocks the cytochrome P450 system and functions as a source of free radicals. 

Individuals should note that this drug is also a mild monoamine oxidase inhibitor (MAOI). The liver is responsible for metabolizing this medication. It is vital to note that some patients metabolize it significantly faster. Thus, research is being done to determine the reason for this difference.

Uses And Benefits 


Isoniazid is most frequently prescribed to treat active tuberculosis. It is almost always used in combination with other medications to prevent the development of treatment-resistant tuberculosis. In some cases, this medication is given to patients who have had a positive TB skin test. This is done in an effort to prevent tuberculosis. Evidence suggests that this antibiotic may be effective in the treatment of meningitis and genito-urinary disease. 

As an antibiotic, this medicine is an effective treatment for many bacterial infections. Of course, like others, it will not treat viral infections. Patients need to take the entire course of medication that has been prescribed. This ensures that they receive the maximum benefits.

Potential Side Effects 


The most common side effects of this medication are nausea, vomiting, and an upset stomach. It may also cause tingling or numbness in the hands and feet. Some patients will have abnormal liver function tests when they are on this drug. Thankfully, serious side effects are less common. However, they can occur. For example, individuals may notice vision changes or pain behind the eyes. 

Other serious side effects include seizures, memory problems, and unusual behavior. Jaundice may occur as well, and some patients may experience bleeding gums or nosebleeds. Patients should call their doctor immediately if they have serious or persistent side effects. They should also inform them if they develop a fever that lasts more than seventy-two hours. 

Precautions To Remember 


Patients need to take precautions with isoniazid. This medication is not safe for use in patients with active liver disease. In addition, those with a history of hepatitis should not take it either. Patients should review their medical history with their doctor before starting this medication. Points of note include having a history of kidney disease, diabetes, HIV, nerve issues, liver disease, or malnourishment. 

Their doctor will also need to know about the patient's alcohol use and if they have ever used injected drugs. Patients thirty-five or older need to have their liver enzymes checked before starting this medicine. In addition, patients must take this medication on an empty stomach. Ideally, they should take it one to two hours before a meal. 

Potential Medication Interactions 


Patients must review their current medications and supplements with their doctor before adding isoniazid. This includes any prescription and over-the-counter medicines. Doing so is vital to reduce the risk of potential medication interactions. Isoniazid interacts with quite a few medications. Examples include acetaminophen, some azole antifungals, and phenytoin. 

It also causes interactions with some depression medications, including MAOIs and SSRIs. Examples of these include fluoxetine, sertraline, and isocarboxazid. Patients on these antidepressants often need to switch to another if they have to take isoniazid. Otherwise, doctors need to prescribe a different antibiotic.