ملخص راكان لل antibiotic PDF

# Anti-bacteria Classification Anti-bacteria classification in three classes: 1. Inhibition of cell wall 2. Inhibition of protein 3. Inhibition of nucleic acid ## Bacteriostatic vs Bactericidal - **Bacteriostatic**: Prevent growing. - **Bactericidal**: Kill the bacteria. ## Bicteral Resistant -...

# Anti-bacteria Classification Anti-bacteria classification in three classes: 1. Inhibition of cell wall 2. Inhibition of protein 3. Inhibition of nucleic acid ## Bacteriostatic vs Bactericidal - **Bacteriostatic**: Prevent growing. - **Bactericidal**: Kill the bacteria. ## Bicteral Resistant - **Risk factors for multidrug-resistant organisms** ## Spectrum of Antibiotics | Spectrum | Description | | ----------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Narrow-spectrum** | Acting only on a single or a limited group of microorganisms. | | **Extended-spectrum** | Modified to be effective against gram-positive and a significant number of gram-negative bacteria. | | **Broad-spectrum** | Affect a wide variety of microbial species. | ## Antibiotics acting on cell wall of bacteria ### Beta Lactams: - **Penicillins:** Mechanism of Action - **Cell Wall Inhibitors** - These drugs are bactericidal. #### Types of Penicillins | Type | Description | | ----------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Natural Pens.** | | | **v.v. Narrow spectrum (Benzyle Penicillins)** | | | **(Antistaphylococal Pens.) Methicillin, Cloxacillin** | | | **Extended-spectrum Pens. (Aminopenicillins) Clavulanic acid + amoxicillin, Sulbactam + ampicillin (IV-IM).** | | | **Antipseudomonal Pens. Piperacillin + tazobactam=** | | #### Penicillins: Clinical Uses - Streptococcal infections (throat infections, - Salmonella infections - Spirochetes (Syphilis) and Gonorrhoea - Rheumatic Fever - Staphylococcal Infections - Prophylactic - in patients with congenital heart disease ### Adverse Effects - Type-1 hypersensitivity reaction - Diarrhoea ### β-Lactamase Inhibitors - **Formulations with β-lactamase inhibitors protect amoxicillin or ampicillin from enzymatic hydrolysis and extends their antimicrobial spectrum.** - Clavulanic acid + amoxicillin - Sulbactam + ampicillin (IV-IM). # Cephalosporins - **First and Second generations CANNOT cross BBB, however, Third and Fourth CAN cross (except cefoperazone),** - **Use for meningitis** - **Clinical Uses:** Meningitis - 3rd and 4th - **Adverse Effects:** - Similar to Penicillins - **Q: Patient has allergic to Penicillins can we use Cephalosporins?** - **About 5-10% show cross-sensitivity between penicillins and cephalosporins. Therefore, patients with history of anaphylaxis to penicillins Will not be treated with a cephalosporin.** # Inhibitors Of Protein Synthesis - **Tetracyclines** - Tetracycline - Doxycycline (vibramycin) - Minocycline - Demeclocycline - **Mechanism of action:** inhibit protein synthesis. - **They are bacteriostatic, prevent growing** - **Broad spectrum used in:** amebiasis, acne, brucellosis, Chlamydia infections - **Adverse effects and contraindications:** Epigastric pain, Teeth discoloration - Fatal Hepatotoxic, Phototoxicity., Vestibular problems - **Aminoglycosides** - Streptomycin - Gentamycin - Tobramycin - **Mechanism of action:** inhibit protein synthesis. - **Bactericidal (needs oxygen-dependent: يحتاج الكسجين عشان يدخل داخل الخلية ويقتلها)** - **Ineffective against anaerobes. عشان مافية اوكسجين** - **Act mainly against gm-ve organisms, pseudomonas.** - **synergistic action) with β-lactam** - **Macrolides** - Erythromycin - Clarithromycin - Azithromycin - **Mechanism of action:** inhibit protein synthesis. - 1-Erythromycin -Drug of choice for patients allergic to penicillins - 2- Clarithromycin: higher activity against H. pylori. - 3- Azithromycin: Drug of choice in Legionellosis - **Adverse effects:** Epigastric pain - **Chloramphenicol** - **Broad spectrum drug (affecting bacteria and rickettsia)** - **Uses:** - Bacterial meningitis - Typhoid fever - **Topically in eye infections.** - **Adverse effects:** - GIT upsets and super infection. - Bone marrow depression. - Gray baby syndrome. # Inhibitors of nucleic acid synthesis - **Quinolones** - 1st generation: Nalidixic acid - 2nd generation: Fluoroquinolones: Ciprofloxacin, Norfloxacin gm -ve - 3rd generation: -Levofloxacin gm +ve - 4th generation: Moxifloxacin anaerobic as well as gm +ve - **Mechanism of action:** Inhibit DNA gyrase (topoisomerase II) - **Uses:** - traveler's diarrhea. - Urinary tract infections - Respiratory tract infection - Bone and soft tissue infection. - **Adverse effects:** - GIT disturbances: the most common. - CNS symptoms, e.g. headache, dizziness. - Tendon rupture (cartilage damage and tendinitis) (in children less than 18 years) - Phototoxicity (should interrupt therapy). ## Folate antagonists ### I-Sulfonamides: Sulfadiazine, sulfamethoxazole - **Mechanism of action:** inhibition of bacterial folate synthesis - **Therapeutic uses:** Eve infections, Ulcerative colitis - Burns: sulfadiazine, Urinary tract infection.Toxoplasmosis - **Adverse effects:** Crystalluria and nephropathy - Hypersensitivity reactions: - Hemopoietic disturbances: ### II-Trimethoprim - 20-50 folds more potent than sulfonamides. ### III- Co-trimoxazole - It is a combination of sulfamethoxazole (400 mg) + trimethoprim (80 mg) 5:1. Bacteriostatic. - **Mechanism of action:** This synergistic combination is due to inhibition of two subsequent steps in the synthesis of folinic acid. - **Advantages:** - More potent - Synergistic combination. - Wider spectrum - **Therapeutic uses:** - Urinary tract infections - GIT infections - Respiratory tract ## Drugs Used in Tuberculosis | Drug | Description | | ----------- | ------------------------------------------------------------------------------------------ | | Isoniazid | Narrow spectrum | | Rifampicin | Reddish Orange discoloration (urine,sweat,saliva) | | Streptomycin | Active against TB | | | **Ototoxicity -Neprhotoxicy** |