What are the possible side effects of Éthambutol?
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Éthambutol can cause serious vision problems, including vision loss that may be permanent. Stop using Éthambutol and call your doctor at once if you have any problems with one or both of your eyes, such as:
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blurred vision or trouble focusing;
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loss of vision in one eye that lasts an hour or longer;
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increased sensitivity of your eyes to light;
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loss of color vision; or
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pain with eye movement, pain behind your eyes.
Call your doctor at once if you have:
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new or worsening cough with fever, trouble breathing;
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numbness of tingling in your hands or feet;
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confusion, hallucinations;
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fever, swollen glands, painful mouth sores, skin sores, cold or flu symptoms, general ill feeling;
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easy bruising or bleeding (nosebleeds, bleeding gums);
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chest pain or shortness of breath with mild exertion;
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little or no urinating;
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liver problems--upper stomach pain, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
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severe skin reaction--fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.
Common side effects may include:
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itching or rash;
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joint pain;
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headache, dizziness; or
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nausea, vomiting, stomach pain, indigestion, loss of appetite.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Side effects of Éthambutol in details
Éthambutol hydrochloride may produce decreases in visual acuity, including irreversible blindness, which appear to be due to optic neuritis. Optic neuropathy including optic neuritis or retrobulbar neuritis occurring in association with Éthambutol therapy may be characterized by one or more of the following events: decreased visual acuity, scotoma, color blindness, and/or visual defect. These events have also been reported in the absence of a diagnosis of optic or retrobulbar neuritis.
Patients should be advised to report promptly to their physician any change of visual acuity.
The change in visual acuity may be unilateral or bilateral and hence each eye must be tested separately and both eyes tested together. Testing of visual acuity should be performed before beginning Éthambutol hydrochloride therapy and periodically during drug administration, except that it should be done monthly when a patient is on a dosage of more than 15 mg per kilogram per day. Snellen eye charts are recommended for testing of visual acuity. Studies have shown that there are definite fluctuations of one or two lines of the Snellen chart in the visual acuity of many tuberculous patients not receiving Éthambutol.
The following table may be useful in interpreting possible changes in visual acuity attributable to Éthambutol.
Initial Snellen Reading | Reading Indicating Significant Decrease | Significant Number of Lines | Decrease Number of Points |
20/13 | 20/25 | 3 | 12 |
20/15 | 20/25 | 2 | 10 |
20/20 | 20/30 | 2 | 10 |
20/25 | 20/40 | 2 | 15 |
20/30 | 20/50 | 2 | 20 |
20/40 | 20/70 | 2 | 30 |
20/50 | 20/70 | 1 | 20 |
In general, changes in visual acuity less than those indicated under "Significant Number of Lines" and "Decrease Number of Points", may be due to chance variation, limitations of the testing method or physiologic variability. Conversely, changes in visual acuity equaling or exceeding those under "Significant Number of Lines" and "Decrease Number of Points" indicate the need for retesting and careful evaluation of the patient’s visual status. If careful evaluation confirms the magnitude of visual change and fails to reveal another cause, Éthambutol should be discontinued and the patient reevaluated at frequent intervals. Progressive decreases in visual acuity during therapy must be considered to be due to Éthambutol.
If corrective glasses are used prior to treatment, these must be worn during visual acuity testing. During 1 to 2 years of therapy, a refractive error may develop which must be corrected in order to obtain accurate test results. Testing the visual acuity through a pinhole eliminates refractive error. Patients developing visual abnormality during Éthambutol treatment may show subjective visual symptoms before, or simultaneously with, the demonstration of decreases in visual acuity, and all patients receiving Éthambutol should be questioned periodically about blurred vision and other subjective eye symptoms.
Recovery of visual acuity generally occurs over a period of weeks to months after the drug has been discontinued. Some patients have received Éthambutol hydrochloride again after such recovery without recurrence of loss of visual acuity. Other adverse reactions reported include: hypersensitivity, anaphylactic/anaphylactoid reaction, dermatitis, erythema multiforme, pruritus, and joint pain; anorexia, nausea, vomiting, gastrointestinal upset, and abdominal pain; fever, malaise, headache, and dizziness; mental confusion, disorientation, and possible hallucinations; thrombocytopenia, leucopenia, and neutropenia. Numbness and tingling of the extremities due to peripheral neuritis have been reported. Elevated serum uric acid levels occur and precipitation of acute gout has been reported. Pulmonary infiltrates, with or without eosinophilia, also have been reported during Éthambutol hydrochloride therapy. Liver toxicities, including fatalities, have been reported.. Since Éthambutol hydrochloride is recommended for therapy in conjunction with one or more other antituberculous drugs, these changes may be related to the concurrent therapy. Hypersensitivity syndrome consisting of cutaneous reaction (such as rash or exfoliative dermatitis), eosinophilia, and one or more of the following: hepatitis, pneumonitis, nephritis, myocarditis, pericarditis. Fever and lymphadenopathy may be present.
What is the most important information I should know about Éthambutol?
- Éthambutol may cause dizziness. This effect may be worse if you take it with alcohol or certain medicines. Use Éthambutol with caution. Do not drive, operate machinery, or perform other possibly unsafe tasks until you know how you react to it.
- Éthambutol may cause decreased vision clearness, including vision loss. This effect may be related to the dose that you take and how long you take Éthambutol. It is usually reversible when Éthambutol is stopped. However, permanent blindness has been reported. Contact your doctor right away if you experience vision changes (eg, decreased vision clearness). Discuss any questions or concerns with your doctor.
- Be sure to use Éthambutol for the full course of treatment. If you do not, the medicine may not clear up your infection completely. The bacteria could also become less sensitive to this or other medicines. This could make the infection harder to treat in the future.
- Éthambutol only works against bacteria; it does not treat viral infections (eg, the common cold).
- Long-term or repeated use of Éthambutol may cause a second infection. Tell your doctor if signs of a second infection occur. Your medicine may need to be changed to treat this.
- Lab tests, including liver and kidney function, complete blood cell counts, and vision, may be performed while you use Éthambutol. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
- Éthambutol should not be used in CHILDREN younger than 13 years old; safety and effectiveness in these children have not been confirmed.
- PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Éthambutol while you are pregnant. Éthambutol is found in breast milk. If you are or will be breast-feeding while you use Éthambutol, check with your doctor. Discuss any possible risks to your baby.
Éthambutol contraindications
Éthambutol hydrochloride is contraindicated in patients who are known to be hypersensitive to this drug. It is also contraindicated in patients with known optic neuritis unless clinical judgement determines that it may be used. Éthambutol hydrochloride is contraindicated in patients who are unable to appreciate and report visual side effects or changes in vision (e.g., young children, unconscious patients).
References
- DailyMed. "ETHAMBUTOL HYDROCHLORIDE: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
- European Chemicals Agency - ECHA. "ethambutol: The European Chemicals Agency (ECHA) is an agency of the European Union which is the driving force among regulatory authorities in implementing the EU's groundbreaking chemicals legislation for the benefit of human health and the environment as well as for innovation and competitiveness.". https://echa.europa.eu/ (accessed September 17, 2018).
- HSDB. "ETHAMBUTOL". https://toxnet.nlm.nih.gov/cgi-bin/s... (accessed September 17, 2018).
Reviews
The results of a survey conducted on ndrugs.com for Éthambutol are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Éthambutol. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.User reports
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Information checked by Dr. Sachin Kumar, MD Pharmacology