Pharmacology Notes PDF

Pharmacology Prepared By: Jonathan Josua B. Guiang, RN What are bacteria, how do they spread, and how can we stop them?  BACTERIA are microscopic, single-celled organisms that can live in various environments—inside and outside the human body. soil, water,...

Pharmacology Prepared By: Jonathan Josua B. Guiang, RN What are bacteria, how do they spread, and how can we stop them?  BACTERIA are microscopic, single-celled organisms that can live in various environments—inside and outside the human body. soil, water, air, and the bodies of every person and animal.​ Bacteria do not have a membrane enclosing their nucleus (part containing DNA)​ Bacteria reproduce on their own (Some need to live in another cell like viruses)​  Spread of diseases​ Touching Sneezing Kissing tiny droplets Sex Infected materials Infected animals Coughing Contaminated surface Talking Coughing Open wounds  Process of Bacterial Invasion and Multiplication 1. Adhesion o Attachment of Bacteria to host cells using surface structures (e.g., pili, fimbriae, adhesins). 2. Colonization o Biofilm Formation: Some bacteria form biofilms, a structured community that adheres to surfaces. * o Nutrient Acquisition: Bacteria extract nutrients from the host.  3. Invasion o Penetration of Host Barriers: Bacteria produce enzymes (e.g., hyaluronidase) to degrade host tissues. Others may utilize endocytosis to invade host cells 4. Evasion of Host Defenses o Avoiding Immune Detection: Mechanisms include capsule formation and antigen variation. 5. Multiplication o Binary Fission: Bacteria replicate through binary fission, dividing into two identical daughter cells. o Protein Synthesis: Essential for cell division; bacteria require proteins for various functions. 6. Spread o Local Spread: Bacteria extend to adjacent tissues, often aided by enzymes or toxins. 7. Systemic Spread o Bacteremia: Some bacteria enter the bloodstream and disseminate throughout the body. 8. Toxin Production o Exotoxins and Endotoxins: Some bacteria produce toxins that damage host tissues.  SIGNS OF INFECTION Local Inflammation: Redness, swelling, heat, and pain at the site of infection (e.g., in cellulitis or wound infections). Fever: A systemic response to bacterial toxins or inflammation. Purulent Discharge: A hallmark of bacterial infections, particularly in wounds or abscesses, indicating pus formation. Fatigue and Malaise: The body’s energy is diverted to fighting the infection, causing general weakness.  GRAM STAINING To identify the kind or type of bacteria To identify antibiotics to be use  GRAM STAINING certain antibiotics work better on gram-positive bacteria, while others are more effective on gram-negative bacteria. Understanding the gram stain helps in selecting the right antibiotic." Bactericidal vs. Bacteriostatic: Bactericidal antibiotics kill bacteria directly, while bacteriostatic antibiotics stop their growth. Broad-Spectrum vs. Narrow-Spectrum: Broad- spectrum antibiotics work against many types of bacteria, while narrow-spectrum antibiotics target specific ones.  ANTI-INFECTIVES Also known as antibacterials, are medications that destroy or slow down the growth of bacteria. Powerful medicines that fight certain infections and can save lives when used properly.  ANTIBIOTIC THERAPY​ Goal: to decrease bacteria so the human immune system can effectively deal with the invader (bacteria).​ Determine the effective antibiotic :culture, sensitivity​ AVOID: Incomplete and OVERUSE OF ANTIBIOTICS ​  Antibiotic Resistance Overuse of Antibiotics: Using antibiotics when they aren’t necessary—such as for viral infections—gives bacteria more chances to adapt. Incomplete Courses: Patients stopping their antibiotic therapy early allows surviving bacteria to become stronger and more resistant ANTI-INFECTIVES Aminoglycosides Carbapenems Cephalosphorins Fluoroquinolones Penicillins and Penicillinase-Resistant Sulfonamides Tetracyclines Antimycobacterials  AMINOGLYCOSIDES Mechanism of Action: Bactericidal action: Aminoglycosides inhibit bacterial protein synthesis by binding irreversibly to the 30S ribosomal subunit leads to bacterial death. Pharmacodynamics: Concentration-dependent killing: The higher the peak concentration, the more bacterial killing occurs.  AMINOGLYCOSIDES Common Drugs and Dosage: 1.Gentamicin: 1. Dosage: 3–5 mg/kg/day IV/IM divided every 8 hours. 2.Tobramycin: 1. Dosage: 3–5 mg/kg/day IV/IM divided every 8–12 hours 2.. 3.Amikacin: 1. Dosage: 15 mg/kg/day IV/IM once daily or divided doses every 12 hours. 4.Streptomycin (used for tuberculosis): 1. Dosage: 15 mg/kg/day IM once daily.  AMINOGLYCOSIDES Clinical Uses: Severe Gram-negative infections: Pseudomonas, E. coli, Klebsiella, and Enterobacter. Combination therapy: Used with beta-lactams or vancomycin for synergy, especially in Gram-positive infections like endocarditis. Tuberculosis: Streptomycin is used in multidrug- resistant TB.  AMINOGLYCOSIDES -They inhibit protein synthesis in susceptible strains of gram-negative bacteria. Pseudomonas aeruginosa, E. coli, Proteus species, the Klebsiella– Enterobacter–Serratia group, Citrobacter species, and Staphylococcusspecies such as Staphylococcus aureus.  AMINOGLYCOSIDES Pharmacokinetics: Absorption: Poorly absorbed from the GI tract, usually given IV or IM. Distribution: Limited to extracellular fluid. Poor penetration into the CNS and lungs unless inflammation is present. Metabolism: Not metabolized. Excretion: Eliminated unchanged by the kidneys; excretion is directly related to renal function.  AMINOGLYCOSIDES Adverse Effects: 1.Nephrotoxicity: Damage to renal tubules, often reversible. 2.Ototoxicity: Irreversible hearing loss or vestibular dysfunction due to damage to the auditory and vestibular nerve. 3.Neuromuscular blockade: Rare but can cause muscle weakness or respiratory paralysis. 4. Allergic reactions: Rare but may occur, causing rash or fever.  AMINOGLYCOSIDES Contraindications: Renal impairment: Use with caution or adjust dosage due to nephrotoxic potential. Myasthenia gravis: Can exacerbate neuromuscular weakness. Pregnancy: Risk of fetal harm, especially ototoxicity to the developing fetus (Category D)  AMINOGLYCOSIDES Nursing Considerations: 1.Monitor renal function: Regularly check serum creatinine and urine output to detect nephrotoxicity. 2.Assess hearing: Baseline and periodic audiograms for ototoxicity. 3.Therapeutic drug monitoring: Ensure appropriate peak and trough levels are achieved and avoid toxicity. 4.Monitor for signs of ototoxicity: Dizziness, tinnitus, or hearing loss.  AMINOGLYCOSIDES 5. Hydration: Ensure the patient is well-hydrated to prevent nephrotoxicity. 6. Synergistic use: When used with beta-lactams, administer beta-lactam first to improve aminoglycoside uptake into bacteria. 7. Neuromuscular monitoring: Watch for respiratory difficulties in at-risk patients (e.g., those with myasthenia gravis).  CARBAPENEMS Mechanism of Action: Bactericidal action: Carbapenems inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), which are essential for peptidoglycan cross-linking in the bacterial cell wall. This results in the weakening of the bacterial cell wall and eventual cell lysis. Broad spectrum: Effective against a wide variety of Gram- positive, Gram-negative, and anaerobic bacteria.  CARBAPENEMS Pharmacodynamics: Time-dependent killing: The effectiveness of carbapenems is based on how long the drug concentration remains above the minimum inhibitory concentration (MIC) rather than how high the concentration gets. Broad-spectrum: Used against multidrug-resistant organisms, but typically reserved to avoid resistance development.  CARBAPENEMS Common Drugs and Dosage: 1. Imipenem-cilastatin: o Dosage: 500 mg–1 g IV every 6–8 hours. 2. Meropenem: o Dosage: 500 mg–2 g IV every 8 hours. 3. Ertapenem: o Dosage: 1 g IV/IM once daily. 4. Doripenem: o Dosage: 500 mg IV every 8 hours. Clinical Uses: CARBAPENEMS Complicated intra-abdominal infections: Due to its effectiveness against anaerobic bacteria. Complicated urinary tract infections (UTIs). Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). Severe skin and soft tissue infections. Bacteremia and sepsis caused by multidrug-resistant organisms. Febrile neutropenia: Used empirically in immunocompromised patients. Polymicrobial infections: Often used for infections with mixed  CARBAPENEMS These drugs are used to treat serious infections caused by susceptible strains of : S. pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, S. aureus, Streptococcus pyogenes, E. coli, Peptostreptococcus, Klebsiella pneumoniae, Clostridium clostridiiforme, Eubacterium lentum, Bacteroides fragilis, Bacteroides dis-tasonis, Bacteroides ovatus, Bacteroides thetaiotamicron, Bacteroides uniformis, Proteus mirabilis, P. aeruginosa, Acinetobacter baumannii, Streptococcus agalactiae, Porphyromonas asaccharolytica, Prevotella bivia,  CARBAPENEMS Pharmacokinetics: Absorption: Poor oral absorption, administered IV or IM. Distribution: Good penetration into most tissues, including the lungs, liver, and kidneys. Limited CNS penetration, but meropenem and imipenem can reach the CNS, especially in cases of meningitis. Metabolism: o Imipenem is metabolized by renal dehydropeptidase (cilastatin is co- administered to prevent this). o Other carbapenems (e.g., meropenem, doripenem) are minimally metabolized. Excretion: Primarily excreted unchanged in the urine. Requires dosage adjustments in patients with renal impairment.  CARBAPENEMS Side Effects: 1. Gastrointestinal: Nausea, vomiting, diarrhea. 2. Infusion reactions: Redness, pain, or swelling at the injection site. 3. Headache. 4. Rash: Mild skin reactions.  CARBAPENEMS Adverse Effects: 1. Seizures: Imipenem, in particular, has a higher seizure risk in patients with a history of seizures or CNS disorders, especially at high doses. 2. Allergic reactions: Carbapenems can cause allergic reactions in individuals allergic to penicillins or other beta-lactams. 3. Clostridioides difficile-associated diarrhea (CDAD): Prolonged use can lead to C. difficile infections due to disruption of normal gut flora. 4. Hepatotoxicity: Elevated liver enzymes, though rare, can occur  CARBAPENEMS Contraindications: Hypersensitivity to carbapenems or other beta- lactams. Severe renal impairment: Dose adjustments are required to prevent accumulation and potential toxicity. Seizure disorders: Caution with imipenem, as it lowers the seizure threshold. Pregnancy and Lactation: Generally considered safe, but only use when clearly indicated.  CARBAPENEMS Nursing Considerations: 1. Monitor for allergic reactions: Be cautious with patients who have a known penicillin allergy. If a reaction occurs, discontinue the drug immediately. 2. Seizure monitoring: For patients receiving imipenem, particularly those with a history of seizures, monitor closely for any signs of seizure activity. 3. Renal function monitoring: Regularly check serum creatinine and adjust dosage as necessary in patients with renal impairment to prevent accumulation and toxicity. 4. Monitor liver function: Check liver enzymes periodically, especially in long-term therapy.  CARBAPENEMS Nursing Considerations: 5. Monitor for signs of superinfection: Prolonged use may lead to fungal infections or C. difficile-associated diarrhea. 6. Hydration status: Ensure patients stay hydrated, especially in cases of diarrhea or gastrointestinal side effects. 7. Infusion site monitoring: Watch for redness, swelling, or pain at the site of injection. 8. Patient education: Advise patients to report any signs of rash, diarrhea, or neurological symptoms like confusion or seizures.  CEPHALOSPORINS Cephalosporins: Overview Mechanism of Action: Bactericidal Action: Cephalosporins inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking. This leads to cell lysis and death. Pharmacodynamics: Time-Dependent Killing: The effectiveness of cephalosporins relies on the duration that the drug concentration remains above the minimum inhibitory concentration (MIC).  CEPHALOSPORINS Common Drugs and Dosage: 1. First Generation (e.g., Cefazolin): o Dosage: 1–2 g IV every 8 hours for serious infections. o Common uses: Surgical prophylaxis, skin infections. 2. Second Generation (e.g., Cefoxitin): o Dosage: 1–2 g IV every 6–8 hours. o Common uses: Intra-abdominal infections, gynecological infections. 3. Third Generation (e.g., Ceftriaxone, Ceftazidime): o Ceftriaxone: 1–2 g IV daily. ▪ Uses: Pneumonia, meningitis, infections caused by resistant organisms. o Ceftazidime: 1–2 g IV every 8 hours.  CEPHALOSPORINS 4. Fourth Generation (e.g., Cefepime): o Dosage: 1–2 g IV every 8–12 hours. o Common uses: Severe infections, including those caused by multidrug-resistant bacteria. 5, Fifth Generation (e.g., Ceftaroline): o Dosage: 600 mg IV every 12 hours. o Common uses: MRSA infections, complicated skin and soft tissue infections.  CEPHALOSPORINS Clinical Uses: Infections: Effective against a wide range of bacteria, including: o Skin and soft tissue infections o Pneumonia o Urinary tract infections (UTIs) o Bone and joint infections o Meningitis (especially third-generation) o Intra-abdominal infections  CEPHALOSPORINS These drugs are used to treat serious infections caused by susceptible strains of : S. pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, S. aureus, Streptococcus pyogenes, E. coli, Peptostreptococcus, Klebsiella pneumoniae, Clostridium clostridiiforme, Eubacterium lentum, Bacteroides fragilis, Bacteroides dis-tasonis, Bacteroides ovatus, Bacteroides thetaiotamicron, Bacteroides uniformis, Proteus mirabilis, P. aeruginosa, Acinetobacter baumannii, Streptococcus agalactiae, Porphyromonas asaccharolytica, Prevotella bivia,  CEPHALOSPORINS Pharmacokinetics: Absorption: Varies by generation; most are administered IV or IM. Oral cephalosporins are well-absorbed (e.g., cefalexin). Distribution: Good tissue penetration, including the CNS for some (especially third-generation). Metabolism: Generally, minimal hepatic metabolism; most cephalosporins are excreted unchanged by the kidneys.  CEPHALOSPORINS Side Effects: Gastrointestinal: Nausea, vomiting, diarrhea. Rash: Skin reactions, including mild rashes. Local Reactions: Pain or swelling at the injection site. Adverse Effects: Allergic Reactions: Risk of anaphylaxis in patients with a history of penicillin allergy. Superinfection: Prolonged use may lead to C. difficile-associated diarrhea. Nephrotoxicity: Rarely, can cause kidney damage, particularly with high doses or in patients with renal impairment.  CEPHALOSPORINS Contraindications: Allergy to Cephalosporins or Penicillins: Caution in patients with a known allergy to beta-lactams. Severe Renal Impairment: Dosage adjustments are necessary. History of Clostridium difficile Infection: Caution due to risk of recurrence.  CEPHALOSPORINS Nursing Considerations: 1. Monitor for Allergic Reactions: Watch for signs of anaphylaxis, especially in patients with a penicillin allergy. 2. Assess Renal Function: Regularly monitor serum creatinine and adjust doses as needed. 3. Educate Patients: Advise on potential side effects and the importance of completing the full course of antibiotics. 4. Monitor for Superinfection: Watch for signs of secondary infections, particularly gastrointestinal symptoms. 5. Check for Drug Interactions: Be aware of interactions with other medications, particularly those affecting renal function.  FLUOROQUINOLONES Fluoroquinolones: Overview Mechanism of Action: Bactericidal Action: Fluoroquinolones inhibit bacterial DNA gyrase and topoisomerase IV, enzymes critical for DNA replication and repair. This leads to the disruption of DNA synthesis and ultimately bacterial cell death. Pharmacodynamics: Concentration-Dependent Killing: The efficacy of fluoroquinolones increases with higher drug concentrations and prolonged exposure above the minimum inhibitory concentration (MIC).  FLUOROQUINOLONES Common Drugs and Dosage: 1. Ciprofloxacin: o Dosage: 250–750 mg orally every 12 hours; 200–400 mg IV every 12 hours. o Uses: UTIs, respiratory infections, skin infections. 2. Levofloxacin: o Dosage: 250–750 mg orally or IV once daily. o Uses: Pneumonia, UTIs, chronic bronchitis exacerbations. 3. Moxifloxacin: o Dosage: 400 mg orally or IV once daily. o Uses: Respiratory infections, skin infections, intra-abdominal infections. 4. Ofloxacin: o Dosage: 200–400 mg orally or IV every 12 hours. Uses: UTIs, respiratory infections, skin infections.  FLUOROQUINOLONES Clinical Uses: Respiratory Infections: Effective for pneumonia and bronchitis. Urinary Tract Infections: Commonly used for complicated and uncomplicated UTIs. Gastrointestinal Infections: Used for certain types of gastrointestinal infections (e.g., travelers' diarrhea). Skin and Soft Tissue Infections: Treatment of various skin infections. Bone and Joint Infections: Effective in treating osteomyelitis.  FLUOROQUINOLONES The fluoroquinolones are indicated for treating infections caused by susceptible strains of gram-negative bacteria, including: E. coli, P. mirabilis, K. pneumoniae, Enterobacter cloacae, Proteus vulgaris, Proteus rettgeri, Morganella morganii, M. catarrhalis, H. infl uenzae, H. parainfl uenzae, P. aeruginosa, Citrobacter freundii, S. aureus, Staphylococcus epidermidis, some Neisseria gonorrhoeae, and group D streptococci  FLUOROQUINOLONES Pharmacokinetics: Absorption: Well-absorbed orally; affected by divalent and trivalent cations (e.g., calcium, magnesium, iron). Distribution: Good penetration into tissues and body fluids, including lungs and urine. Metabolism: Minimal hepatic metabolism; primarily eliminated unchanged in urine. Excretion: Renal excretion; dose adjustments may be needed in renal impairment.  FLUOROQUINOLONES Side Effects: Gastrointestinal: Nausea, diarrhea, abdominal pain. CNS Effects: Headache, dizziness, insomnia. Skin Reactions: Rash and photosensitivity. Adverse Effects: Tendon Rupture: Increased risk, particularly in older adults and those on corticosteroids. QT Interval Prolongation: Risk of arrhythmias, especially with moxifloxacin. Neuropathy: Risk of peripheral neuropathy, particularly in patients with diabetes. C. difficile Infection: Risk of developing C. difficile-associated diarrhea.  FLUOROQUINOLONES Contraindications: Allergy to Fluoroquinolones: Avoid use in patients with a known allergy to this class. Myasthenia Gravis: Can exacerbate symptoms. Pregnancy and Lactation: Generally avoided due to potential risks to the fetus or nursing infant.  FLUOROQUINOLONES Nursing Considerations: 1. Monitor for Side Effects: Assess for gastrointestinal symptoms and CNS effects. 2. Educate Patients: Instruct on the importance of hydration and avoiding antacids containing calcium or magnesium within a few hours of taking the medication. 3. Assess Tendon Health: Instruct patients to report any signs of tendon pain or swelling, particularly in the Achilles tendon. 4. Renal Function Monitoring: Check renal function in patients receiving long-term therapy or those with renal impairment. 5. QT Interval Monitoring: Monitor ECG in patients with risk factors for prolonged QT interval.  PENICILLINS Penicillins: Overview Mechanism of Action: Bactericidal Action: Penicillins inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking, which leads to cell lysis and death. Pharmacodynamics: Time-Dependent Killing: The effectiveness is based on the time the drug concentration remains above the minimum inhibitory concentration (MIC).  PENICILLINS Common Drugs and Dosage: 1. Natural Penicillins (e.g., Penicillin G, Penicillin V): o Penicillin G: 1–5 million units IV every 4–6 hours. o Penicillin V: 250–500 mg orally every 6–8 hours. o Uses: Streptococcal infections, syphilis, and some staphylococcal infections.  PENICILLINS 2. Aminopenicillins (e.g., Amoxicillin, Ampicillin): o Amoxicillin: 250–500 mg orally every 8 hours or 875 mg every 12 hours. o Ampicillin: 1–2 g IV every 4–6 hours. Uses: Otitis media, sinusitis, pneumonia, and urinary tract infections  PENICILLINS 3. Penicillinase-Resistant Penicillins (e.g., Methicillin, Nafcillin, Oxacillin): o Methicillin: 1–2 g IV every 4 hours (note: rarely used due to resistance). o Nafcillin: 1–2 g IV every 4–6 hours. o Oxacillin: 1–2 g IV every 4–6 hours. o Uses: Serious infections caused by penicillinase-producing Staphylococcus aureus (MSSA).  PENICILLINS Clinical Uses: Infections: Effective for a variety of infections including: o Skin and soft tissue infections o Respiratory tract infections o Endocarditis o Meningitis (with appropriate formulations)  PENICILLINS :The penicillins are indicated for the treatment of streptococcal infections, including pharyngitis, tonsillitis, scarlet fever, and endocarditis; pneumococcal infections; staphylococcal infections; fusospirochetal infections; rat-bite fever; diphtheria; anthrax; syphilis; and uncompli-cated gonococcal infections. At high doses, these drugs are also used to treat meningococcal meningitis  PENICILLINS Pharmacokinetics: Absorption: Generally good absorption for oral forms, but food can affect some formulations. Distribution: Good tissue penetration; limited CNS penetration unless in inflammation. Metabolism: Minimal hepatic metabolism; primarily excreted unchanged by the kidneys. Excretion: Requires dose adjustments in renal impairment  PENICILLINS Side Effects: Gastrointestinal: Nausea, vomiting, diarrhea. Allergic Reactions: Rash, itching, fever. Local Reactions: Pain or swelling at the injection site. Adverse Effects: Anaphylaxis: Serious allergic reactions, particularly in patients with a history of penicillin allergy. Superinfection: Risk of C. difficile-associated diarrhea and other superinfections due to disruption of normal flora. Seizures: High doses, especially in renal impairment, may lead to seizures  PENICILLINS Contraindications: Allergy to Penicillins: Avoid in patients with a known allergy to penicillin or related antibiotics. Severe Renal Impairment: Adjust doses as necessary. History of Anaphylactic Reactions: Use caution or avoid in patients with a history of anaphylaxis.  PENICILLINS Nursing Considerations: 1. Monitor for Allergic Reactions: Be vigilant for signs of anaphylaxis, especially in patients with a history of allergies. 2. Educate Patients: Instruct patients to complete the full course of therapy and report any side effects. 3. Renal Function Assessment: Regularly monitor renal function, especially in patients on high doses or prolonged therapy. 4. Gastrointestinal Monitoring: Watch for signs of gastrointestinal distress and potential superinfection. 5. Medication Interactions: Be aware of potential interactions with other medications that may affect renal function or absorption.  SULFONAMIDES SULFONAMIDES: NURSING PHARMACOLOGY GUIDE 1. Mechanism of Action: Inhibition of Folic Acid Synthesis: Sulfonamides act as competitive inhibitors of the enzyme dihydropteroate synthase. This enzyme is critical in the bacterial synthesis of dihydrofolic acid, which is a precursor for folic acid. By blocking this step, sulfonamides prevent bacteria from synthesizing DNA, RNA, and proteins, which are essential for their growth and replication. Bacteriostatic: These drugs inhibit bacterial growth rather than killing bacteria outright.  SULFONAMIDES 2. Pharmacodynamics: Bacteriostatic Action: Sulfonamides stop bacterial growth by interfering with folic acid metabolism. Effective only in organisms that synthesize their own folic acid (i.e., bacteria),  SULFONAMIDES 3. Drug Dosage: Sulfamethoxazole-Trimethoprim (SMX-TMP): o Adults: 800 mg SMX / 160 mg TMP every 12 hours (common for UTIs, PCP pneumonia). o Pediatric: Dosed based on weight; commonly 8 mg TMP / 40 mg SMX per kg/day divided every 12 hours. Sulfadiazine: o Adults: 1-2 grams orally every 6-12 hours, depending on the infection. o Pediatric: 75 mg/kg every 12 hours (for specific infections like toxoplasmosis).  SULFONAMIDES 4. Clinical Uses: Urinary Tract Infections (UTIs): Commonly used to treat E. coli- caused infections. Pneumocystis jirovecii pneumonia (PCP): Frequently used in immunocompromised patients (e.g., HIV/AIDS). Acute Otitis Media: Often combined with other antibiotics. Toxoplasmosis: Especially in combination with pyrimethamine. Traveler’s Diarrhea: In some cases, sulfonamides are used. Certain Skin Infections: Can be effective in some cases of MRSA  SULFONAMIDES - This includes gram-negative and gram-positive bacteria such as Chlamydia trachomatis and Nocardia and some strains of H. influenzae, E. coli, and P. mirabilis.  SULFONAMIDES. Pharmacokinetics: Absorption: Sulfonamides are generally well-absorbed orally. Distribution: Widely distributed in body tissues and fluids, including the cerebrospinal fluid (CSF), pleural fluid, and synovial fluid. Metabolism: Primarily metabolized by the liver via acetylation. Excretion: Primarily excreted through the kidneys (glomerular filtration and tubular secretion), which can lead to crystalluria if proper hydration is not maintained. Half-life: Depends on the specific drug (e.g., sulfamethoxazole has a half-life of about 10 hours, while sulfadiazine's half-life is around 10-12 hours).  SULFONAMIDES 6. Side Effects: GI Symptoms: Nausea, vomiting, diarrhea, and anorexia. Photosensitivity: Increased risk of sunburn and skin irritation. Rash: Mild skin rashes are common.  SULFONAMIDES 7. Adverse Effects: Stevens-Johnson Syndrome (SJS): A serious and potentially life-threatening skin reaction characterized by blisters and peeling skin. Toxic Epidermal Necrolysis (TEN): A more severe form of SJS. Blood Dyscrasias: Includes hemolytic anemia, aplastic anemia, thrombocytopenia, and leukopenia. Crystalluria: Formation of crystals in the urine, which can lead to kidney damage or acute kidney injury (AKI). Hyperkalemia: Especially when using sulfamethoxazole-trimethoprim (SMX-TMP) in patients with renal dysfunction. Hypersensitivity Reactions: Ranging from mild rash to anaphylaxis.  SULFONAMIDES 8. Contraindications: Pregnancy (3rd trimester): Sulfonamides can cause kernicterus (bilirubin-induced brain damage) in newborns. Neonates (under 2 months): Due to risk of kernicterus. Severe Renal or Hepatic Impairment: Risk of accumulation and toxicity. Sulfa Allergy: Patients with a known hypersensitivity to sulfonamides should avoid them.  SULFONAMIDES NURSING RESPONSIBILITY 1.Assess for any history of sulfa allergy or hypersensitivity reactions. 2. Monitor renal function (BUN, creatinine) before and during treatment, especially in elderly patients or those with pre-existing renal conditions. 3. Encourage fluid intake of at least 1.5-2 liters/day to help flush the drug from the kidneys and prevent crystal formation. 4. Give with or without food; food may reduce GI upset but can slightly delay absorption. 5. Advise patients to avoid direct sunlight or wear protective clothing and use sunscreen due to photosensitivity. 6. Hydrate adequately to prevent crystalluria and maintain proper kidney function.  TETRACYCLINES Tetracyclines: Overview Mechanism of Action: Bacteriostatic Action: Tetracyclines inhibit bacterial protein synthesis by binding to the 30S ribosomal subunit, preventing the attachment of aminoacyl-tRNA to the mRNA-ribosome complex. Pharmacodynamics: Time-Dependent Killing: The effectiveness is related to the duration that the drug concentration remains above the minimum inhibitory concentration (MIC). Common Drugs and Dosage: TETRACYCLINES 1. Tetracycline: o Dosage: 250–500 mg orally every 6 hours. o Uses: Acne, respiratory infections, and urinary tract infections. 2. Doxycycline: o Dosage: 100 mg orally or IV every 12 hours; can switch to 100 mg once daily after initial doses. o Uses: Lyme disease, acne, and respiratory tract infections. 3. Minocycline: o Dosage: 200 mg initially, then 100 mg every 12 hours. o Uses: Acne, respiratory infections, and some drug-resistant infections. 4. Oxytetracycline: o Dosage: 250–500 mg orally every 6 hours. o Uses: Various infections, including those caused by Rickettsia.  TETRACYCLINES Clinical Uses: Acne: Treatment of moderate to severe acne. Respiratory Infections: Community-acquired pneumonia and chronic bronchitis exacerbations. Tick-Borne Diseases: Lyme disease and Rocky Mountain spotted fever. Chlamydia: Treatment of chlamydial infections. Malaria: Used in combination therapy for malaria prophylaxis and treatment.  TETRACYCLINES Tetracyclines are indicated for treatment of infections caused by Rickettsiae, Mycoplasma pneumoniae, Borrelia recurrentis, H. infl uenzae, Haemophilus ducreyi, Pasteurella pestis, Pasteurella tularensis, Bartonella bacilliformis, Bacteroides species, Vibrio comma, Vibrio fetus, Brucella species, E. coli, E. aerogenes, Shigella species, Acinetobacter calcoaceticus, Klebsiella species, Diplococcus pneumoniae, and S. aureus; against agents that cause psittacosis, ornithosis, lymphogranuloma venereum, and granuloma inguinale  TETRACYCLINES Pharmacokinetics: Absorption: Generally well-absorbed; absorption can be reduced by food, antacids, and minerals (calcium, magnesium). Distribution: Widely distributed in tissues; penetrates well into the CNS and other fluids. Metabolism: Metabolized in the liver; some are excreted unchanged in urine. Excretion: Renal and biliary; dose adjustments may be necessary in severe renal impairment.  TETRACYCLINES Side Effects: Gastrointestinal: Nausea, vomiting, diarrhea, and esophageal irritation. Photosensitivity: Increased risk of sunburn and skin reactions. Tooth Discoloration: Permanent discoloration of teeth in children. Adverse Effects: Hepatotoxicity: Rarely, can cause liver damage. Pseudomembranous Colitis: Risk of C. difficile infection with prolonged use. Intracranial Hypertension: Rare but can occur, especially with high doses of doxycycline.  TETRACYCLINES Contraindications: Allergy to Tetracyclines: Avoid in patients with a known hypersensitivity. Pregnancy: Generally contraindicated due to potential harm to the fetus (tooth discoloration). Children Under 8 Years: Risk of permanent tooth discoloration.  TETRACYCLINES Nursing Considerations: 1. Monitor for Side Effects: Assess for gastrointestinal symptoms and photosensitivity reactions. 2. Educate Patients: Instruct on sun protection and avoiding antacids or supplements within 2 hours of taking the medication. 3. Assess Liver Function: Monitor liver function tests if prolonged therapy is anticipated. 4. Hydration: Encourage fluid intake to prevent esophageal irritation.  ANTIMYCOBACTERIALS Antimycobacterials: Overview Mechanism of Action: Bactericidal/Bacteriostatic Action: Antimycobacterials (e.g., isoniazid, rifampicin) target various bacterial processes: o Isoniazid: Inhibits mycolic acid synthesis, essential for mycobacterial cell walls. o Rifampicin: Inhibits bacterial RNA polymerase, preventing RNA synthesis. Pharmacodynamics: Concentration-Dependent Killing: The effectiveness is enhanced at higher concentrations, particularly for rifampicin.  ANTIMYCOBACTERIALS Common Drugs and Dosage: 1. Isoniazid (INH): o Dosage: 300 mg orally daily; can be given as 15 mg/kg for children. o Uses: Tuberculosis (TB) treatment and prevention. 2. Rifampicin: o Dosage: 10 mg/kg orally daily (maximum 600 mg). o Uses: Tuberculosis, leprosy, and some staphylococcal infections. 3. Pyrazinamide: o Dosage: 15 mg/kg orally daily (maximum 2 g). o Uses: Tuberculosis (part of combination therapy). 4. Ethambutol: o Dosage: 15 mg/kg orally daily. o Uses: Tuberculosis, often used in combination therapy.  ANTIMYCOBACTERIALS Clinical Uses: Tuberculosis: First-line agents for treating active and latent TB. Leprosy: Used in combination therapy for leprosy. Other Mycobacterial Infections: Certain atypical mycobacterial infections. Pharmacokinetics: Absorption: Well-absorbed orally; some are affected by food. Distribution: Good penetration into body tissues, including the lungs and CNS. Metabolism: Primarily hepatic; isoniazid is acetylated by the liver. Excretion: Mostly renal; dose adjustments may be needed in hepatic impairment.  ANTIMYCOBACTERIALS Side Effects: Gastrointestinal: Nausea, vomiting, loss of appetite. Neuropathy: Isoniazid can cause peripheral neuropathy (often preventable with pyridoxine). Hepatotoxicity: Risk of liver damage, especially with isoniazid and rifampicin. Adverse Effects: Rifampicin: Can cause orange-red discoloration of urine, sweat, and tears; hepatotoxicity. Isoniazid: Risk of seizures and encephalopathy in overdose situations.  ANTIMYCOBACTERIALS Nursing Considerations: 1. Monitor Liver Function: Regular liver function tests in patients on isoniazid and rifampicin. 2. Educate Patients: Inform about potential side effects, especially discoloration of body fluids with rifampicin. 3. Assess for Neuropathy: Monitor for symptoms of peripheral neuropathy in patients on isoniazid. 4. Compliance: Stress the importance of adherence to the full course of therapy for TB treatment  ANTIMYCOBACTERIALS Contraindications: Allergy: Avoid in patients with a known hypersensitivity to these drugs. Severe Liver Disease: Caution with use in patients with significant hepatic impairment.