lec 3 cemotherapy of infections........pptx

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1. Chemotherapy of infections

2. Classification of Antimicrobial agents Antibiotics : Antibiotic is a chemical secreted by microorganisms (bacteria) that kills or hinders the growth of some kinds of bacteria. Examples.  Penicillin and streptomycin . Antifungal Agents: Target fungi (e.g., fluconazole for Candida infections). Antiparasitic Agents: Target parasites (e.g., chloroquine for malaria).

3. Mode of action of antimicrobial agents

4. Combination of Antimicrobial agents A combination of antimicrobial agents refers to the use of two or more antimicrobial drugs simultaneously to treat infections. There are several reasons why combinations may be used:

5. Purpose : Preventing disease before exposure or after exposure but before clinical symptoms appear Examples of Diseases Common diseases where chemoprophylaxis is used (e.g., malaria, tuberculosis, HIV) Indications Criteria for using chemoprophylaxis
High-risk populations (e.g., travellers to endemic areas, healthcare workers)

6. Penicillin Penicillin are β-lactam antibiotics that inhibit bacterial cell wall synthesis. They are classified into several groups based on their spectrum of activity and resistance to β-lactamase enzymes. Here are some classes of penicillin Natural penicillin (Penicillin G and Penicillin V) Penicillinase-resistant penicillin Aminopenicillins Extended-spectrum penicillin Beta-lactamase inhibitors

7. Spectrum of Activity of penicillin: The spectrum of activity varies among different penicillin: Narrow-spectrum penicillin (such as penicillin G and V) are effective against Gram-positive bacteria like Streptococcus and some Gram-negative cocci. Broad-spectrum penicillin (such as ampicillin, amoxicillin), have enhanced activity against Gram-negative bacteria in addition to Gram-positive bacteria.

8. Routes of Administration: Penicillin G: Typically administered intravenously (IV) or intramuscularly (IM) due to poor oral bioavailability. Penicillin V: Can be administered orally and is often used for less severe infections. Dose Generally, for adults, a typical dose might range from 250 mg to 500 mg every 4 to 6 hours. Adverse Effects: Common adverse effects of penicillin include:
Allergic reactions
Nausea, vomiting, diarrhea.
High doses of certain penicillin can lead to seizures.

9. Cephalosporin Cephalosporin are a class of antibiotics that share a similar chemical structure to penicillin. There are 5 generations of cephalosporin. Spectrum of Activity : First-generation cephalosporin primarily target gram-positive bacteria, while later generations have increasing activity against gram-negative bacteria. Dose For oral administration: Typically, doses range from 250 mg to 500 mg every 12 hours for adults.
For intravenous administration: Doses can range from 1 to 2 grams every 6 to 12 hours depending on the severity of the infection.

10. Route of Administration: Cephalosporin can be administered orally or intravenously, depending on the formulation and severity of the infection Adverse Effects: Nausea, vomiting, diarrhea
Hypersensitivity reactions
Pseudomembranous colitis (associated with Clostridium difficile infection)
Hematologic effects (such as thrombocytopenia or leukopenia)

11. Aminoglycosides Aminoglycosides are a class of antibiotics that inhibit bacterial protein synthesis. Classes are systematic and topical aminoglycosides. Spectrum of Activity: Aminoglycosides are effective against a wide range of gram-negative bacteria. They are also used in combination with other antibiotics to treat serious gram-positive infections . Routes of Administration: Aminoglycosides can be administered intravenously (IV) or intramuscularly (IM). Some formulations can also be given orally, although this is less common due to poor absorption.

12. Dose: The dosing of aminoglycosides depends on factors such as the specific drug used, patient's weight, renal function, and the site and severity of infection. Adverse Effects: Common adverse effects of aminoglycosides include nephrotoxicity (kidney damage), ototoxicity (damage to the inner ear), and neuromuscular blockade (especially at high doses).

13. Tetracycline's Tetracycline are a group of broad-spectrum antibiotics that inhibit bacterial protein synthesis. They are classified based on their chemical structure and include: Natural tetracycline : e.g., tetracycline, oxytetracycline Semi-synthetic tetracycline : e.g., doxycycline, minocycline Spectrum of Activity: Tetracycline are effective against a wide range of bacteria, both Gram-positive and Gram-negative, as well as certain atypical bacteria

14. Dose : The dosage of tetracycline's can vary depending on the specific drug, the severity of the infection, and the patient's age and weight. Typical doses for adults might be: Tetracycline: 250-500 mg every 6 hours Doxycycline: 100-200 mg once or twice daily Minocycline: 100-200 mg initially, followed by 50 mg every 12 hours Routes of Administration: Tetracycline's are available in various forms for administration:
Oral tablets or capsules
Intravenous (IV) injection

15. Adverse Effects: Tetracycline's can cause several adverse effects, including: Nausea, vomiting, diarrhea, and abdominal discomfort. Photosensitivity Discoloration of teeth Hepatotoxicity: Elevated liver enzymes in some patients. Renal Toxicity Allergic Reactions

16. Chloramphenicol Chloramphenicol is a broad-spectrum antibiotic belonging to the class of bacteriostatic agents. It inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit. Spectrum of Activity: Chloramphenicol has activity against a wide range of bacteria, both Gram-positive and Gram-negative. Route of Administration: Chloramphenicol can be administered via: oral, intravenous and topical

17. Dose Adults : 500 mg to 1 gram every 6 hours orally, or 50-100 mg/kg/day Children : 12.5-25 mg/kg every 6 hours orally Intravenous dosing adjusted based on weight and severity of infection. Adverse effects Bone marrow suppression Grey baby syndrome Allergic reactions

18. Tubercular drugs Tuberculosis (TB) drugs can be categorized based on their mechanism of action and role in treatment. Classified as;- First-line Drugs (Primary TB Drugs): Isoniazid (INH)
Rifampicin (RIF)
Pyrazinamide (PZA)
Ethambutol (EMB) Second line drugs Fluoroquinolones etc.

19. Spectrum of Activity: First-line drugs : Effective against Mycobacterium tuberculosis, the bacterium causing TB. They are Second-line drugs : Used when TB is resistant to first-line drugs or in cases of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB). Routes of Administration: Oral: Most TB drugs are administered orally.
Injectable: Some second-line drugs are administered via intramuscular or intravenous routes.

20. Adverse effects Hepatotoxicity.
Flu-like Syndrome
Orange Discoloration of Body Fluids
Hyperuricemia
Gastrointestinal Upset Dose Isoniazid (INH): 5 mg/kg/day
Rifampicin (RIF): 10 mg/kg/day
Pyrazinamide (PZA): 25 mg/kg/day
Ethambutol (EMB): 15-25 mg/kg/day