Actions of Ethbutol in details
Description: Ethbutol appears to inhibit the synthesis of 1 or more metabolites in susceptible bacteria resulting in impairment of cellular metabolism, arrest of multiplication, and cell death. It is active against susceptible bacteria only when they are undergoing cell division.
Pharmacokinetics:
Absorption: 80% is absorbed from the GI tract. Time to peak plasma concentration: W/in 4 hr.
Distribution: Distributed in most tissues, including lungs, kidneys, erythrocytes. Approx 10-50% may diffuse into CSF when meninges are inflamed. Crosses the placenta and enters breast milk.
Metabolism: Undergoes partial hepatic metabolism;, converted to the aldehyde and dicarboxylic acid derivatives (inactive).
Excretion: Via urine (as unchanged drug, 8-15% as metabolites) and faeces (20% as unchanged drug). Elimination half-life: Approx 3-4 hr.
How should I take Ethbutol?
Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not take this medicine in larger or smaller amounts or for longer than recommended.
Tell your doctor if you have ever used tuberculosis medicine before. Your dose may be different if you have been treated for tuberculosis in the past.
You may take Ethbutol with or without food.
Ethbutol may be taken with food if it upsets your stomach.
Tell your doctor if you have any changes in weight. Ethbutol doses are based on weight and your dose may also need to be changed.
Your vision will need to be checked often while you are taking Ethbutol. If you wear glasses, take them with you to your vision examination.
Your blood cells, kidney function, and liver function may also need to be checked.
Use this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Ethbutol will not treat a viral infection such as the flu or a common cold.
Tuberculosis is sometimes treated with a combination of drugs. Use all medications as directed by your doctor. Read the medication guide or patient instructions provided with each medication. Do not change your doses or medication schedule without your doctor's advice.
Store at room temperature away from moisture and heat.
Ethbutol administration
Take Ethbutol exactly as directed by your doctor. If you do not understand these instructions, ask your pharmacist, nurse, or doctor to explain them to you.
Take each dose with a full glass (8 ounces) of water.
Ethbutol can be taken with or without food. Taking Ethbutol with food may decrease stomach upset.
Take all of the Ethbutol that has been prescribed for you even if you begin to feel better. Your symptoms may begin to improve before the infection is completely treated.
Ethbutol is usually combined with one or more other tuberculosis medicines.
Store this medication at room temperature away from moisture and heat.
Ethbutol pharmacology
Ethbutol, following a single oral dose of 25 mg/kg of body weight, attains a peak of 2 to 5 mcg/mL in serum 2 to 4 hours after administration. When the drug is administered daily for longer periods of time at this dose, serum levels are similar. The serum level of Ethbutol falls to undetectable levels by 24 hours after the last dose except in some patients with abnormal renal function. The intracellular concentrations of erythrocytes reach peak values approximately twice those of plasma and maintain this ratio throughout the 24 hours.
During the 24-hour period following oral administration of Ethbutol approximately 50 percent of the initial dose is excreted unchanged in the urine, while an additional 8 to 15 percent appears in the form of metabolites. The main path of metabolism appears to be an initial oxidation of the alcohol to an aldehydic intermediate, followed by conversion to a dicarboxylic acid. From 20 to 22 percent of the initial dose is excreted in the feces as unchanged drug. No drug accumulation has been observed with consecutive single daily doses of 25 mg/kg in patients with normal kidney function, although marked accumulation has been demonstrated in patients with renal insufficiency.
Ethbutol diffuses into actively growing Mycobacterium cells such as tubercle bacilli. Ethbutol appears to inhibit the synthesis of one or more metabolites, thus causing impairment of cell metabolism, arrest of multiplication, and cell death. No cross resistance with other available antimycobacterial agents has been demonstrated.
Ethbutol has been shown to be effective against strains of Mycobacterium tuberculosis but does not seem to be active against fungi, viruses, or other bacteria. Mycobacterium tuberculosis strains previously unexposed to Ethbutol have been uniformly sensitive to concentrations of 8 or less mcg/mL, depending on the nature of the culture media. When Ethbutol has been used alone for treatment of tuberculosis, tubercle bacilli from these patients have developed resistance to Ethbutol (Ethbutol) by in vitro susceptibility tests; the development of resistance has been unpredictable and appears to occur in a step-like manner. No cross resistance between Ethbutol and other antituberculous drugs has been reported. Ethbutol has reduced the incidence of the emergence of mycobacterial resistance to isoniazid when both drugs have been used concurrently. An agar diffusion microbiologic assay, based upon inhibition of Mycobacterium smegmatis (ATCC 607) may be used to determine concentrations of Ethbutol in serum and urine.
Animal Pharmacology
Toxicological studies in dogs on high prolonged doses produced evidence of myocardial damage and failure, and depigmentation of the tapetum lucidum of the eyes, the significance of which is not known. Degenerative changes in the central nervous system, apparently not dose-related, have also been noted in dogs receiving Ethbutol over a prolonged period. In the rhesus monkey, neurological signs appeared after treatment with high doses given daily over a period of several months. These were correlated with specific serum levels of Ethbutol and with definite neuroanatomical changes in the central nervous system. Focal interstitial carditis was also noted in monkeys which received Ethbutol in high doses for a prolonged period.
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).
- NCIt. "Ethambutol: NCI Thesaurus (NCIt) provides reference terminology for many systems. It covers vocabulary for clinical care, translational and basic research, and public information and administrative activities.". https://ncit.nci.nih.gov/ncitbrowser... (accessed September 17, 2018).
- EPA DSStox. "Ethambutol: DSSTox provides a high quality public chemistry resource for supporting improved predictive toxicology.". https://comptox.epa.gov/dashboard/ds... (accessed September 17, 2018).
Reviews
The results of a survey conducted on ndrugs.com for Ethbutol 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 Ethbutol. 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
