The document presents information on the anti-tubercular agent ethambutol. It begins with an introduction on tuberculosis and the need for combination drug therapy to overcome bacterial resistance. It then classifies anti-TB drugs as first-line and second-line based on efficacy and toxicity. Details provided on ethambutol include its classification as a synthetic, bacteriostatic antibiotic, pharmacokinetics of absorption, distribution mainly to tissues except CSF, metabolism and 50% excretion unchanged in urine. The clinical use, common side effects and precautions for ethambutol are summarized.

1. Presentation on
Anti tubercular agents
Presented by
Sohana Habib
Roll:557
Department of Pharmacy

2. Content
• Introduction
• Classification
• Ethambutol
• Pharmacokinetics
• Distribution
• Elimination
• Clinical use
• Side effects
• Precaution

3. Introduction
• Tuberculosis – most important communicable disease in the world .
• Mycobacteria are intrinsically resistant to most antibiotics
- Grows more slowly than other bacteria – antibiotics active against
rapidly growing cells
- It grows inside macrophage –poorly penetrated by drugs
-Excellent ability to develop resistance –multiple drug resistant
(MDR)
• Combination of two or more drugs
-to overcome these obstacles
-to prevent emergence of resistance during the course of therapy.

4. Classification
• According to clinical utility the anti TB drugs can be divided
into 2 groups
1. First Line : high antitubercular efficacy as well as low
toxicity –routinely used
e.g. Isoniazid , Rifampin, Streptomycin, Ethambutol .
2. Second Line : low antitubercular efficacy or high toxicity
e.g. Paraminosalicylic Acid, cycloserine , kanamycin,
Amikacin, ciprofloxacin.

5. Ethambutol
• Ethambutol is used with other medications to treat tuberculosis
(TB).
• Ethambutol is an antibiotic and works by stopping the growth
of bacteria.
• Synthetic , water soluble , heat stable ,
• Bacteriostatic
• Development of resistance .

6. Pharmacokinetics
• Well absorbed from the gut.
• 20% of the drug is excreted in feces and 50% in urine in
unchanged form
• Crosses the blood-brain barrier only when the meninges are
inflammed.
• Temporarily stored in RBC.
• T ½ -4 hrs
• Caution taken for renal failure patient.

7. 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.

8. Elimination
• Renal; by glomerular filtration and tubular secretion upto 80%
excreted whithin 24 hrs.
• Fecal ; 20% excreted unchanged.
• In dialysis-
ethambutol is removed from the blood by hemodialysis
and peritoneal dialysis.

9. Clinical use
• Ethambutol hydrochloride - 15-25 mg/kg/d
• Higher dose is recommended for treatment of tuberculous
meningitis
• 50 mg/kg when a twice-weekly dosing schedule .

10. Common side effects
• Itching or rash
• Joint pain
• Headache , dizziness or
• Nausea, vomiting, stomach pain , indigestion , loss of appetite.

11. Precautions
• Before taking ethambutol , tell your doctor or pharmacist if
you are allergic to it because it may contain inactive
ingredients, which can cause allergic reaction.
• Ethambutol generally is not recommended in children whose
visual acuity cannot be monitored (younger than 6 years of
age)
• It is not recommended for pregnant women ; because
ethambutol may cross the placenta.