What Are the Most Common Ethambutol Side Effects?

Ethambutol hydrochloride interferes with DNA and RNA synthesis of Mycobacterium tuberculosis, and has a strong inhibitory effect on Mycobacterium tuberculosis during growth and reproduction. It has no cross-resistance with other anti-TB drugs. Long-term use can slowly develop resistance. Clinically used in patients who are resistant to streptomycin or isoniazid. Combined with rifampicin or isoniazid, it can enhance the efficacy and delay the development of drug resistance, and treat various types of active tuberculosis.

Ethambutol hydrochloride

Ethambutol hydrochloride interferes with DNA and RNA synthesis of Mycobacterium tuberculosis, and has a strong inhibitory effect on Mycobacterium tuberculosis during growth and reproduction. It has no cross-resistance with other anti-TB drugs. Long-term use can slowly develop resistance. Clinically used in patients who are resistant to streptomycin or isoniazid. Combined with rifampicin or isoniazid, it can enhance the efficacy and delay the development of drug resistance, and treat various types of active tuberculosis.

Drug Name

Ethambutol hydrochloride

Alias

Hyambutol, EB

Foreign name

Ethambutol Hydrochloride

Main indications

For the treatment of atypical Mycobacterium tuberculosis infection

Adverse reactions

Visual acuity

Main ingredients of medicine

Ethambutol hydrochloride

Ethambutol hydrochloride

Drug Name: Ethambutol Hydrochloride

Indications: 1 Pharmacology This product is a synthetic antibacterial tuberculosis drug. It has strong activity against bacteria during growth and reproduction, and has little effect on bacteria at rest. High antibacterial activity against all types of mycobacteria. There is no cross-resistance between Mycobacterium tuberculosis and this drug. The mechanism of action of this product has not been fully elucidated. It may be related to inhibiting the metabolism of sensitive bacteria, inhibiting the synthesis of RNA, and interfering with the protein metabolism of Mycobacterium tuberculosis, leading to bacterial death. 2. Toxicology This product can cause cleft palate, brain exposure and

Oral, adults and children (over 13 years old), start 25mg / kg daily, 2 to 3 times / day; usually take 15mg / kg after 8 weeks, and then take it. Need to be combined with other anti-TB drugs. 1. Initial treatment: Orally, according to body weight 15mg / kg, once a day; or 25-30mg / kg once, up to 2.5g, three times a week; or 50mg / kg, up to 2.5g twice a week. 2. Retreatment: Orally, 25mg / kg once a day for 60 consecutive days, followed by 15mg / kg once a day. 3 Atypical Mycobacterium tuberculosis infection: 15 to 25 mg / kg, once a day. [Drug overdose] 1. Drug overdose is mainly manifested in the symptoms described in [Adverse Reactions]. In severe cases, permanent optic nerve atrophy can occur. 2. Treatment of overdose (1) Discontinue the drug. (2) Symptomatic treatment: Those with posterior optic neuritis can use vitamin B6, multivitamins, and zinc-copper preparations. To restore vision, 5mg of dexamethasone can be used as a daily intravenous infusion or post-ball injection; tolasurin 12.5mg can be administered as a post-ball injection; hydrocortisone 200mg can be administered as an intravenous infusion daily. Prednisone 20mg can also be taken orally 2 to 3 times a day. Vitamins are given at the same time. During the recovery period, acupuncture treatment can be given, oral dibazole, niacin, etc., or daily intramuscular injection of placental tissue fluid. Perform hemodialysis and peritoneal dialysis if necessary.

(1) Those who have a higher incidence are blurred vision, eye pain, red-green blindness or vision loss, and reduced visual field (optics neuritis is easy to occur when the daily weight is above 25mg / kg). Changes in vision can be unilateral or bilateral. (2) Less frequent cases are chills, joint swelling and pain (especially big toes, ankles, knee joints), and skin fever and tightness on the joint surface (acute gout, hyperuricemia). (3) Less frequent cases are allergic reactions such as rash, fever, joint pain; or numbness, acupuncture, burning pain, or weakness in hands and feet (peripheral neuritis).

Pregnancy class B. Use with caution in patients with alcoholism, allergies to this product, gout, optic neuritis, renal dysfunction, and patients younger than 13 years of age. Due to the narrow safety threshold of ethambutol, the dose must be strictly administered. 1. Gout, optic neuritis, diabetic fundus disease, liver and kidney function should be used with caution. Patients with reduced renal function should be reduced. 2. This product alone can quickly develop drug resistance, so it must be used in combination with other anti-TB drugs. 3 Check during the treatment: (1) Eyes, visual field, vision, red and green discrimination, etc., check once a month before the medication and during the course of treatment, especially for patients with a long course of treatment and a daily dose of more than 15 mg / kg. (2) Since this product can increase the concentration of uric acid in the blood and cause gout attacks, the serum uric acid should be measured regularly during the course of treatment. 4 Interference to diagnosis: Taking this product can increase the measured value of blood uric acid concentration. 5. If gastrointestinal irritation occurs, this product can be taken with food. The daily dose may not reach the effective blood concentration, so the daily dose of this product should be taken once. [Medication for pregnant and lactating women] 1. Because this product can penetrate the placenta, the fetal blood concentration is about 30% of the maternal blood concentration. Animal experiments have shown that this product can cause deformities. Although no problem has been confirmed in humans, pregnant women should still disable this product Pros and cons should be fully weighed when taking indications. 2. This product can be secreted into milk, and its concentration is similar to the blood concentration of the mother. Therefore, this product is forbidden for lactating women. If there are indications, lactation should be suspended. [Medication for children] There is no clinical data for children under 13 years of age. Because it is not easy to monitor vision changes in young children, this product is not suitable for children under 13 years of age; the dosage of children over 13 years is the same as that of adults. [Medication for elderly patients] Due to physiological renal dysfunction in elderly patients, the dosage should be adjusted according to renal function.

1 Mainly posterior optic neuritis, with decreased sensitivity, impaired color discrimination, narrowed visual field, and dark spots. Patients should be reminded to report abnormal vision and report to the doctor in a timely manner.

2 Gastrointestinal reactions, including nausea, vomiting, and diarrhea.

3 Occasional allergic reactions. Have liver dysfunction, numbness of the lower limbs, joint pain, agranulocytosis, and mental symptoms such as hallucinations, restlessness, insomnia, or hyperuricemia.

4 Patients with diabetes, alcoholism and infants are prohibited. Pregnant women and those with renal insufficiency should be used with caution.

Method name: Determination of ethambutol hydrochloride-neutralization titration method

Scope of application: This method uses titration to determine the content of ethambutol hydrochloride.

This method is applicable to ethambutol hydrochloride.

Principle of the method: After the test product is dissolved with glacial acetic acid slightly, the mercury acetate test solution and crystal violet indicator solution are added, and then the solution is titrated with perchloric acid titration solution (0.1mol / L) until the solution becomes blue-green. The perchloric acid titration is recorded. The amount of fluid used is calculated.

Reagent: 1. Water (new boiling to room temperature)

2. Perchloric acid titrant (0.1mol / L)

3. Crystal violet indicator liquid

4. Methyl red-bromocresol green mixed indicator liquid

5. Bromothymol blue indicator liquid

6. Acetic anhydride

7. Glacial acetic acid

8. Mercury acetate test solution

9. Reference potassium hydrogen phthalate

equipment:

Sample preparation: 1. Perchloric acid titration solution (0.1mol / L)

Preparation: Take 750mL of anhydrous glacial acetic acid (calculated with water content, add 5.22mL acetic anhydride per 1g of water), add 8.5mL perchloric acid (70% -72%), shake well, and slowly add acetic anhydride dropwise at room temperature. 23mL, shake while adding, shake evenly after adding, let cool, add an appropriate amount of anhydrous glacial acetic acid to 1000mL, shake well, and leave for 24 hours. If the test sample is easily acetylated, the water content on this page must be determined by moisture measurement, and then the water content of this solution should be adjusted to 0.01% -0.2% with water and acetic anhydride.

Calibration: Take about 0.16g of standard potassium hydrogen phthalate dried to constant weight at 105 , accurately weigh, add 20mL of anhydrous glacial acetic acid to dissolve, add 1 drop of crystal violet indicator solution, and titrate slowly with Blue, and the results of the titration are corrected with a blank test. Each 1mL of perchloric acid titration solution (0.1mol / L) is equivalent to 20.42mg of potassium hydrogen phthalate. Calculate the concentration of this solution based on the consumption of this solution and the amount of potassium hydrogen phthalate taken.

Storage: Place in a brown glass bottle and keep tightly closed.

2. Crystal violet indicator liquid

Take 0.5g of crystal violet, add 100mL of glacial acetic acid to dissolve, and get.

3. Methyl red-bromocresol green mixed indicator liquid

Take 20 mL of 0.1% methyl red ethanol solution, add 30 mL of 0.2% bromocresol green ethanol solution, and shake to obtain.

4. Bromothymol blue indicator liquid

Take 0.1g of bromothymol blue, add 3.2mL of 0.05mol / L sodium hydroxide solution to dissolve, and dilute to 200mL with water.

Operation steps: Precisely weigh 0.1g of test sample, add 20mL glacial acetic acid to dissolve slightly, add 5mL mercury acetate test solution and 1 drop of crystal violet indicator solution, and titrate the solution with perchloric acid titrant (0.1mol / L) It is blue-green, and the result of the titration is corrected by a blank test. The volume of perchloric acid titrant consumed (mL) is recorded. Each 1 mL of perchloric acid titrant (0.1mol / L) is equivalent to 29.59mg of ethambutol hydrochloride. Alcohol (C10H24N2O2 · 2HCl).

Note 1: "Precision weighing" means that the weighed weight should be accurate to one thousandth of the weight. Precision requirements.

References: Pharmacopoeia of the People's Republic of China, compiled by the National Pharmacopoeia Committee, Chemical Industry Press, 2005 edition, Part Two, p.455.