Ethambutol is an antibiotic used primarily with other medications to treat tuberculosis and certain serious infections like mycobacterium avium complex, especially in advanced HIV patients. It works by inhibiting bacterial growth and is excreted largely unchanged in urine. Potential side effects include hepatitis, peripheral neuritis, and optic neuritis, with caution advised in patients with pre-existing eye or kidney issues.

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

2.  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.  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.  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. It is well absorbed from
the gastrointestinal tract and well
distributed in body tissues and
fluids. 50% is excreted unchanged in
urine.

6.  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.  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.  Up to 15% of ethambutol is metabolized to
inactive metaboliteIsoniazid—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.  Ethambutol:
2 to 5 mcg/mL after a single dose of 25
mg/kg.

10.  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.  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.  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. 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.  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.  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.  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.  » 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.  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