Rifampin and Isoniazid (Oral)

As a major drug in the fight against tuberculosis, oral rifampin and isoniazid tackles the bacterial infection in the lungs or elsewhere.

Overview

Oral rifampin and isoniazid is a drug designed to be taken by those suffering from tuberculosis (TB). As a combined antibiotic and anti-infective drug, it works by fighting the mycobacterium tuberculosis bacteria which cause the infection in the lungs or elsewhere, which ultimately can reduce your symptoms.

This medication is only available with a prescription from a physician. In the USA it has the brand names IsonaRif and Rifamate, which means you may see it labelled up in this way in stores and pharmacies. It is available both as a capsule and as a tablet.

Conditions Treated

Type of Medicine

  • Antibiotic
  • Anti-infective

Side Effects

Taking medication is the best method for reducing the symptoms or removing the cause of an illness, but unfortunately extra symptoms can sometimes emerge - known as side effects - as the medication gets to work inside your body.

As with any medication, side effects are possible as a result of taking oral rifampin and isoniazid. There is no guarantee that you will or will not experience a particular side effect, as the experience of every patient is different.

That said, there are some general categories of side effects which are published as a guide to what you may expect when taking this medication.

Common side effects

The first category of side effects are those which are classed as more common, but which require immediate medical attention. In the event that you experience any of these side effects, you should consult a physician or healthcare professional right away. If they are unavailable, you should attend the nearest emergency room and you - or someone who is with you - should inform the staff at that location that you are taking oral rifampin and isoniazid.

Side effects in this category include dark urine, experiencing clumsiness or a feeling of being unsteady, or excessive fatigue. A yellow tint over the eyes or skin, as well as numbness or burning in the hands or feet, are also considered serious side effects. Some stomach and digestion related problems are also in this category, including a lack of appetite for eating, a feeling of nausea or a wave of vomiting.

Less common side effects

There are also some less common side effects which still require immediate medical attention. Included in this category are problems like a fever, chills, shivering, dizziness, difficulty breathing and headache. Also included in this category is itching of the skin, pain in the bones or muscles, or a rash or red skin.

Rare side effects

The final category of side effects which require medical attention right away are those which are classed as even less common, or rare, in incidence. Although for most patients it is unlikely that you will experience these problems, you should be aware of them in order to act should you experience them.

Side effects in this category include mental problems such as mood changes or depression. Also included is blood in the urine, less frequent passing of urine, blurred vision, problems with the throat, convulsions and more. Unexpected bleeding patterns or bruising are also included.

In addition to the above side effects which require immediate medical attention, you may also experience other side effects which do not necessarily require attention from a physician.

This is because these problems are simply normal reactions of the body to the medication, and often go away on their own. The only time you would need to consult a physician in relation to these side effects is if they are causing you lots of problems or if they persist. If you're worried about the arrival of these side effects, you can ask your physician or another healthcare professional to give you advice and tips on mitigating or dealing with the problems.

More common side effects in this category include diarrhea and stomach upset. Less common side effects in this category include experiencing a sore mouth or tongue.

Remember, these lists of side effects are not necessarily exhaustive. You should always consult your physician if you have any problems.

Dosage

When it comes to arranging a dosage for you, your physician will take into account all sorts of different factors which are bespoke to you. For that reason, you should always follow their instructions.

You should also follow the instructions given to you by your physician regarding other aspects of dosage, such as the frequency of dosages required or any special requirements.

That said, there is some general dosage information available which is offered as a guide to those who wish to know about what they may or may not be prescribed when they visit their physician.

For those patients who are taking oral rifampin and isoniazid in capsule form to treat tuberculosis, the standard dosage for adults and older children is different for each one of the two combined drugs. 300 milligrams (mg) of isoniazid is usually prescribed, to be taken once a day, while 600 mg of rifampin is generally prescribed as well.

This medication is not usually prescribed to children as its usage is not recommended for this age group.

If you discover that this drug causes you to experience stomach upsets, you can take it with antacid medications or food. You should not take any antacids which contain aluminium for a one hour period around taking oral rifampin and isoniazid, as this could interfere with the workings of the medication.

In addition to the dosage provided by your physician, there are also some possible requirements concerning how to take the medication which are specific to oral rifampin and isoniazid. For example, your physician may prescribe you additional medication to deal with the effects the main oral rifampin and isoniazid can cause. Pyridoxine, for example, can help your body deal with the effects of taking isoniazid. If you are prescribed this medication to assist you, you should take it every day and avoid missing doses.

If you miss a dose of your oral rifampin and isoniazid, you should decide what to do based on how long it will be until the next dosage of the medication needs to be taken. If you remember you have missed a dose and it is close to the time of the missed dose, go ahead and take it as normal. If, however, it is close to the time of the next dose, you should skip the missed dose, take the next one as normal and then continue your schedule as normal. It is very important that you do not ever take a double dose of this medication.

It is very important that you continue to take your oral rifampin and isoniazid for the full duration of its course unless advised otherwise by your physician, even if you begin to feel better during the course. This is because your tuberculosis may return should you not complete the full course.

Interactions

Many medications can cause interactions with other drugs and substances once inside the human body.

Your physician cannot, however, make an accurate judgement about what to do without first knowing what medications you are currently taking. As a result, you should always provide your medical professionals with a full and comprehensive list of any medications you are currently taking, plus any over the counter medications you use.

Once your physician has this information, they may choose to alter the configuration of your current medication in order to prevent any problems with interactions.

Some of the other drugs which can interact with oral rifampin and isoniazid include some well known and common medications, including acetylsalicylic acid (also known as aspirin), Wellbutrin (bupropion), paracetamol (acetaminophen), Zinc (zinc sulfate) and more.

Various vitamins can also interact with oral rifampin and isoniazid. These include Vitamin C (ascorbic acid), Vitamin D3 (cholecalciferol), Vitamin B2 (riboflavin), Vitamin D2 (ergocalciferol), Vitamin B6 (pyridoxine) and more.

Altogether, there are well over 800 drugs which are known to interact with oral rifampin and isoniazid. Once again, this means it is vital that your physician is aware of the drugs you are currently taking, as there is a chance that one or more of them may clash with oral rifampin and isoniazid.

This drug can also interact with alcohol, and as a result, it is recommended that patients avoid drinking alcohol or cut down when taking this medication. This is because the medication can affect your liver.

Warnings

As with all medications, there is a number of warnings which come associated with taking oral rifampin and isoniazid.

This is not necessarily an exhaustive list of warnings associated with this drug. The full list of warnings should be provided on the information booklet which comes with your drugs, so you should consult that before taking this medication.

Often, it may seem like not all of the warnings apply to you, but it is worth reading them in full to ensure you don't miss any which could be relevant to your personal medical situation.

If you are taking any oral contraceptive pills, known as birth control, which contain the hormone estrogen, you should be aware that it's possible for your birth control to fail to work while you are taking oral rifampin and isoniazid. For that reason, you should opt for another family planning method while using this medication.

It is also advised that patients with vision problems do not use soft contact lenses while taking oral rifampin and isoniazid. This is because the medication can cause the lenses to become discoloured on a permanent basis. There are no warnings against using hard contact lenses while oral rifampin and isoniazid is being taken, so it is OK to do this.

You should be aware that many bodily fluids may turn a different colour while taking oral rifampin and isoniazid, often a shade mixing red, orange and brown. The bodily fluids affected by this include the saliva, sweat, tears, urine and more. This is to be expected, and is not a cause for concern.

Patients are advised that they should take care when consuming certain foodstuffs while taking this medicine, as the isoniazid can react to some of the components of the food. Foodstuffs in this category include seafood like skipjack and tuna as well as certain types of cheese like Swiss cheese or Cheshire cheese. Although the chances of an interaction like this occurring are low, if you experience side effects like chills, a headache, sweating or more while taking this medication and eating foods like this, you should consult your physician.

Patients on this medication should also be aware that blood problems can arise as a result of taking the drugs. For example, the risks are higher of slower healing from cuts, bleeding from areas like the gums and contracting some infections. As a result, you should avoid having any dental work undertaken while you are on this medication, as it could cause unusual levels of bleeding. In addition, you should ensure you take care when using dental floss, toothbrushes or similar implements, as they too can cause problems.

Storage

When it comes to storing your oral rifampin and isoniazid, there are some important measures you need to take. These are designed to protect not just your own health and safety but also that of those who come into your home or who may come into contact with the drug.

Ensure that your oral rifampin and isoniazid is kept out of the reach of children at all times. This is to reduce the risk of any accidental consumption which could occur should children come into contact with the medication. Even if you do not have any children living with your in your home, it's still a good idea to make sure you store them away just in case children come to visit in the future and you forget to move them.

Do not keep any leftover oral rifampin and isoniazid you do not plan to use in the future, and remember to ensure that any medication you do keep is in date. If it is not, you should dispose of it. You should never stop taking your oral rifampin and isoniazid unless advised to by a physician. However, in the event that you have leftover oral rifampin and isoniazid, you need to take steps to ensure it is disposed of in the correct way to prevent it from falling into the wrong hands. If you are unsure how to go about doing this, you should speak to a healthcare professional to find out more.

Finally, you should ensure that you always keep your oral rifampin and isoniazid stored in a place free from adverse environmental conditions. These can include areas of direct light, as well as sources of strong heat and moisture. Never place your oral rifampin and isoniazid in the freezer or subject it to freezing conditions, as doing this may damage its effectiveness.

Summary

Oral rifampin and isoniazid is designed to treat and reduce the symptoms of tuberculosis by attacking the bacterial infection which causes the illness. Working as both an antibacterial drug and an anti-infective drug, the combination can only be prescribed by a physician and has a number of alternative brand names in the USA.

As with many medications, side effects can arise as a result of taking this medication. These can include serious side effects which require emergency medical attention, such as shivering, chills, vomiting and a yellow tint over the eyes or skin. In the event that you experience any of the conditions on this list, you should visit your physician or an emergency room straight away. Some less serious side effects, such as stomach upsets, do not require medical treatment unless they persist or are causing you lots of problems.

Standard dosage information for this drug is available, but you should always follow the instructions given to you by your physician on everything from precise dosage to frequency of dosages. This medication is not usually prescribed to children. In the event that this medication causes stomach upsets, you are able to take it with food. If you miss a dose of this medication, you should only take the missed dose if it is still a long time until your next one. You should not stop taking this medication until its course ends unless directed to by your physician, even if you begin to feel better.

This drug can interact with a number of other drugs once inside the human body, including some which are available over the counter. For that reason, you should always give your physician a complete list of the drugs you are already taking so that an informed decision can be taken on whether or not to re-adjust your current configuration of medication.

There are a number of warnings associated with this drug, and you should always consult the list placed on the information booklet which comes with the drug - even if you do not think any of them will apply to you. In addition, you should always store this medication in a place out of direct light or sources of a high amount of heat, and you should keep it out of the reach of children.

 

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Last Reviewed:
January 30, 2018
Last Updated:
January 27, 2018