Ethambutol by arif khan

Ethambutol is used with other medications to treat tuberculosis (TB). Ethambutol is an antibiotic and works by stopping the growth of bacteria.

1. Ethambutol Presented by :ARIF KHAN 4 th GROUP 5 th YEAR

2. Ethambutol Ethambutol  is used with other medications to treat tuberculosis (TB). Ethambutol is an antibiotic and works by stopping the growth of bacteria. This antibiotic treats only  bacterial infections. It will not work for viral infections (such as common cold, flu). Unnecessary use or misuse of any antibiotic can lead to its decreased effectiveness

3. OTHER USES: This drug may also be used with other medications to help treat a certain serious infection (Mycobacterium avium complex-MAC). It may also be used with other medications to prevent the MAC infection from occurring again in people with advanced HIV disease . It is sold under the trade names  Myambutol  and  Servambutol .

4. Mechanism of action/Effect: Ethambutol diffuses into actively growing  M. tuberculosis  such as tubercle bacilli. Ethambutol 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 antimicrobial agents has been demonstrated.

5. Pharmacokinetics/ Absorption: It is well absorbed from the gastrointestinal tract and well distributed in body tissues and fluids. 50% is excreted unchanged in urine.

6. Distribution: Ethambutol is distributed to most tissues and body fluids, except CSF. Ethambutol does not penetrate intact meninges , but 10 to 50% may penetrate the meninges of patients with tuberculous meningitis.

7. Protein binding: Rifampin —High to very high (89 %). Isoniazid —Very low (0 to 10 %). Pyrazinamide —Low (10 to 20 %). Pyrazinoic acid—Low (approximately 31 %). Ethambutol —Low (20 to 30 %).

8. Biotransformation: Up to 15% of ethambutol is metabolized to inactive metabolite Isoniazid—1 to 2 hours {08} {09} . Pyrazinamide—1 to 2 hours Pyrazinoic acid—4 to 5 hours Ethambutol—2 to 4 hours Time to peak serum concentration Rifampin—1.5 to 4 hours after oral administration

9. Peak serum concentration Ethambutol : 2 to 5 mcg/ mL after a single dose of 25 mg/kg.

10. Elimination: Ethambutol —         Renal; by glomerular filtration and tubular secretion; up to 80% excreted within 24 hours (at least 50% excreted unchanged and up to 15% as inactive metabolites ).    Fecal; 20% excreted unchanged. In dialysis—          ethambutol is removed from the blood by hemodialysis and peritoneal dialysis.

11. Side Effects Incidence more frequent: Hepatitis  (dark urine; yellow eyes or skin)      hepatitis prodromal symptoms  (loss of appetite; nausea and vomiting; unusual tiredness or weakness)      peripheral neuritis  (clumsiness or unsteadiness; numbness, tingling, burning, or pain in hands and feet )

12. “Flu-like” syndrome  (chills; difficulty in breathing; dizziness; fever; headache; muscle and bone pain; shivering)      gouty arthritis, acute  (chills; pain and swelling of joints, especially big toe, ankle, or knee; tense, hot skin over affected joints)      hypersensitivity  (itching; redness; skin rash ). Incidence less frequent     

13. Blood dyscrasias  (sore throat; unusual bleeding or bruising)      interstitial nephritis  (bloody or cloudy urine; greatly decreased frequency of urination or amount of urine)      neurotoxicity  (seizures; mental depression; mood or other mental changes )      retrobulbar optic neuritis  (blurred vision or loss of vision, with or without eye pain ). Incidence rare

14. PRECAUTIONS: Before taking ethambutol , tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems .  Before using this medication, tell your doctor or pharmacist your medical history, especially of:  eye problems (such as optic neuritis, cataracts, diabetic retinopathy),liver disease, kidney disease, alcohol use.

15. PRECAUTIONS cont: Ethambutol crosses the placenta, resulting in fetal plasma concentrations that are approximately 30% of maternal plasma concentrations. However, problems in humans have not been documented.

16. Drug interactions and/or related problems Disulfiram     (concurrent use in alcoholics may result in increased incidence of CNS effects such as dizziness, incoordination , irritability, or insomnia; reduced dosage or discontinuation of disulfiram may be necessary.

17. Overdose: For specific information on the agents used in the management of rifampin , isoniazid , pyrazinamide , and ethambutol overdose, : •   Pyridoxine (Systemic)  in monograph; •   Diazepam  in  Benzodiazepines ( Systemic) monograph ; and/or •   Thiopental  in  Barbiturates (Systemic)  monograph.

18. Before using this medication Conditions affecting use, especially: Hypersensitivity to rifampin , isoniazid , pyrazinamide , ethionamide , niacin (nicotinic acid), rifabutin , rifapentine , or other chemically related medications Pregnancy— Rifampin , isoniazid , and ethambutol cross the placenta Breast-feeding— Rifampin , isoniazid , pyrazinamide , and ethambutol are distributed into breast milk Use in children—— Ethambutol generally is not recommended in children whose visual acuity cannot be monitored (younger than 6 years of age)

19. Precautions while using this medication »  Regular visits to physician to check progress, as well as ophthalmologic examinations if signs of optic neuritis occur »  Checking with physician if no improvement within 2 to 3 weeks »  Using an alternate method of contraception if taking estrogen-containing oral contraceptives concurrently »  Avoiding alcoholic beverages while taking this medication »  Checking with physician if vascular reactions occur following concurrent ingestion of cheese or fish with isoniazid -containing medication »  Checking with physician if blurred vision or loss of vision occurs »  Medication causes urine, feces, saliva, sputum, sweat, and tears to turn reddish-orange to reddish-brown and may also permanently discolor soft contact lenses; avoiding the wearing of soft contact lenses

20. References http:// www.drugs.com/mmx/rifampin-isoniazid-pyrazinamide-and-ethambutol.html http://www.webmd.com/drugs/2/drug-8082/ethambutol-oral/details # http:// www.medicinenet.com/ethambutol-oral/page2.htm