Ethambutol (Oral)

Overview

Ethambutol is an antibiotic which is widely used in the treatment of patients with tuberculosis (TB). Antibiotics are only able to fight infections which have been caused by bacteria within the body. They are not able to treat infections caused by viruses, such as influenza.

Antibiotics function by attacking parts of the bacteria cell which are not present in human cells. There is, therefore, no need for the medication to be able to distinguish between human and bacterial cells, the drug can safely attack any cells it finds without causing harm to the human body. Ethambutol in particular works by inhibiting the bacterial cells from being able to build a cell wall. As none of the cells in the human body have a cell wall, this will only have an effect on the bacteria present.

As with all antibiotics, using Ethambutol unnecessarily or for too long can lead to them becoming less effective at stopping the bacteria from growing and reproducing. The bacteria are able to adapt and become resistant to medications over time, such is the case with the MRSA superbug.

Conditions Treated

Type Of Medicine

  • Antibiotic

Side Effects

As with many medications, there is a risk that Ethambutol may cause unwanted side effects alongside the treatment it offers. When prescribing medication, doctors and pharmacists will weigh up the benefit of the drug against the potential risk of side effects. If you are prescribed a certain type of medication, it will be because the healthcare professional in question believes that the benefits to your health outweigh the potential negative side effects. Most patients who are treated with Ethambutol do not experience any side effects. Occasionally, one or more of the following minor side effects may be experienced whilst taking Ethambutol:

  • Abdominal cramps
  • Headaches
  • Lack of appetite
  • Confusion
  • Nausea
  • Vomiting

The side effects listed above can usually be managed by other medication or treatments. Patients experiencing these side effects as a result of taking Ethambutol only need to seek medical attention if they are particularly severe or long-lasting.

In rare cases, patients may experience the following major side effects as a result of taking Ethambutol:

  • Chills or fever
  • Pain in the joints
  • Swollen knees, ankles or toes
  • Taught skin which is hot to the touch over swollen joints
  • Rashes
  • Weakness, numbness or pins and needles in the feet and/or hands
  • Color blindness
  • Blurred vision
  • Pain in the eye

Patients who suffer from any of the symptoms listed above whilst taking Ethambutol, or not long after finishing a course of treatment which includes Ethambutol, should seek immediate medical attention. It may be that alternative treatment methods are required or that doctors will be able to help find a way to keep these side effects under control.

Dosage

The usual dose of Ethambutol prescribed to adults with tuberculosis is an initial treatment of 15mg per day for a duration of between six and eight weeks. This dose is usually prescribed alongside isoniazid therapy which is conducted at the same time. If the patient is undergoing retreatment for tuberculosis, a dose of 25mg is usually prescribed to be taken daily for up to 60 days alongside other treatments. After 60 days this dose is often lowered to the initial 15mg dose. In some cases, larger doses of Ethambutol are administered several times a week rather than smaller doses being given daily.

The prescribed dose of Ethambutol will vary according to the following factors:

  • The condition being treated
  • The age of the patients
  • Other health conditions the patient may be suffering from
  • Whether or not the patient has kidney or liver problems
  • The severity of the illness
  • Whether or not the patient has been hospitalized

Patients should not change their dose or miss out doses without medical advice. The course of antibiotics should be completed in full, even if the patient starts to feel better before the end of the treatment.

Ethambutol can be taken with or without food. Patients may find it easier to take the Ethambutol at the same time each day. This will ensure the optimum time between doses. If you miss out a dose, take the missed one as soon as you remember, unless it is close to the time of the next dose, in which case you should skip the missed one and carry on with the treatment. Patients should not take two doses in one go even if they missed the previous one.

Interactions

Although all medications which are prescribed by doctors and qualified healthcare professionals will have been tested and deemed safe to use, they are still powerful chemicals. Sometimes, these chemicals can interact with other substances within the body and can cause unintended harmful effects on the patient or their course of treatment. Interactions between two or more medications can cause the treatment to be less effective, can increase the severity of symptoms or side effects and can, in some cases, cause dangerous and potentially life-threatening conditions.

It is not possible to list all of the substances which may interact with Ethambutol as some interactions may not have been discovered yet. Here is a list of some of the pharmaceuticals which are currently known to cause interactions or contraindications when combined with Ethambutol:

  • Fluticasone
  • Diphenhydramine
  • Fluconazole
  • Rifabutin
  • Esomeprazole
  • Albuterol
  • Salmeterol
  • Ipratropium
  • Guaifenesin
  • Montelukast
  • Tiotropium
  • Formoterol
  • Budesonide
  • Acetaminophen
  • Levothyroxine
  • Cetirizine

If you are taking any of these drugs listed above, make sure that your doctor or pharmacist is aware, as they may have to adjust your treatment in order to avoid harmful interactions.

It is not just pharmaceuticals which can interact with each other. Some dietary supplements are known to interact with Ethambutol with potentially damaging effects. Patients should speak to their doctor and seek medical advice before taking any of the following whilst receiving treatment with Ethambutol:

  • Multivitamins
  • Vitamin B6
  • Vitamin B12
  • Vitamin C
  • Vitamin D3
  • Vitamin D2
  • Aluminum

In order to be best prepared against interactions, patients should ensure that they always take an accurate, up-to-date and comprehensive list of the medications they are currently taking or have recently been taking when they attend medical consultations and check-ups. This will enable doctors to be able to find a treatment plan which avoids interactions between medications wherever possible.

Warnings

Ethambutol is a powerful medication which should only be taken if prescribed by a doctor. There is a possibility that in addition to treating tuberculosis, it could have a negative effect on some pre-existing conditions or cause difficulties for certain types of patient. It is therefore very important to let your doctor know if any of the following statements are true:

  • You are allergic to Ethambutol or have previously had an allergic reaction to any of the ingredients in the medication
  • You have an allergy to any other form of medication
  • You have on-going inflammation of the eye
  • You have an eye condition, poor vision, are partially-sighted or have ever had a problem with one or both eyes.
  • You have recently experienced changes in your eyesight
  • You suffer from or have ever suffered from gout
  • You are pregnant or plan on becoming pregnant soon
  • You are breastfeeding or plan to breastfeed in the near future
  • You have a kidney condition or have ever had problems with your kidneys
  • You have liver disease or have ever experienced problems with your liver

Ethambutol can be harmful to children under the age of 13 and is therefore only prescribed to children if absolutely necessary.

In order to protect the patient against potentially harmful interactions between Ethambutol and medical conditions other than tuberculosis, doctors will ask for a full and comprehensive medical history. It is vital that this is correct and that nothing is omitted from the record, no matter how minor it may seem.

Do not stop, start or change the dose of a course of Ethambutol without first talking to your doctor or pharmacist.

Storage

As with all forms of medication, Ethambutol should be stored in its original packaging, as provided by the doctor or pharmacist. It should be clearly labelled so that it cannot be confused with other forms of medication. If any instructions were provided with the medication, these should be stored in the same place so that they can be easily referenced if necessary.

Ethambutol should be stored somewhere dry which is not exposed to large differences in temperature. Bathrooms cabinets are exposed to too much moisture, so patients are advised to keep their medication elsewhere. There may be circumstances in which patients will need to take their Ethambutol medication out and about with them. The same instructions should be observed when out of the house, and it is even more important to ensure that the medication is clearly labelled with your name and the type of drug contained inside.

Ethambutol should be safely stored out of the reach of pets and children at all times.

If for any reason you need to dispose of this medication, do so in a safe and controlled manner. Ethambutol should not be placed in the household trash or be flushed down the toilet. Instead, it should be returned to a hospital, pharmacy or clinic which operates a medicine take-back program. The medication will then be disposed of safely by a qualified professional.

Summary

Ethambutol is a type of antibiotic which plays a crucial role in the treatment of patients with tuberculosis. It works by attacking TB bacteria, stopping them from being able to develop a cell wall. This prevents them from being able to grow and multiply, thereby reducing the infection.

It is a strong medication, only available via prescription. Care should, therefore, be taken to keep the drug stored safely, out of the reach of children, pets and those who may mistake it for their own medication.

There is always a danger with antibiotics that they will become less effective the longer they are being taken. This is particularly difficult with treatment for TB as patients are most likely to be prescribed a longer course of antibiotic treatment than is usual for other bacterial infections. It is therefore extremely important for patients to follow dosage instructions carefully and to not continue to take the drug for longer than has been advised by their doctor.