Pharmacology: Anti-Infectives & Antibiotics

What are Gram-Positive Bacteria?

Bacteria with a thick peptidoglycan wall that retains purple stain.

What are Gram-Negative Bacteria?

Bacteria with a thin cell wall that loses purple stain.

How do Aerobic and Anaerobic Bacteria differ?

Aerobic bacteria require oxygen to survive; anaerobic bacteria do not.

What is the purpose of Culture and Sensitivity Testing?

Culture identifies the causative organism; sensitivity determines effective drug treatments.

What is Empiric Therapy?

Treatment initiated based on likely pathogens before exact organism identification.

What are the Four Antibiotic Mechanism Families?

Cell wall, protein, DNA/RNA, and folic acid synthesis inhibitors.

What is the mechanism of Cell Wall Inhibitors?

Weakens bacterial wall, causing osmotic swelling and cell lysis.

What allows for the Selective Toxicity of Cell Wall Inhibitors?

Human cells lack cell walls, providing a drug target unique to bacteria.

What is the mechanism and key drugs of Penicillin?

Inhibits cell wall synthesis; includes amoxicillin, penicillin G, and Augmentin.

What is the function of Clavulanic Acid?

Protects amoxicillin from destruction by bacterial penicillinase enzymes.

What is the trend across Cephalosporin Generations?

Higher generations gain greater gram-negative coverage and better CNS penetration.

What is the cross-sensitivity risk between Penicillins and Cephalosporins?

Patients allergic to penicillin risk hypersensitivity reactions with cephalosporins.

What is the spectrum and drug interaction of Carbapenems?

Broadest beta-lactams; combining with valproic acid increases seizure risk.

What are the features of Aztreonam (Monobactam)?

Covers gram-negative bacteria only; safe for penicillin-allergic patients.

What precaution is required for Vancomycin Infusion?

Must be infused slowly to prevent red man syndrome.

What are the Boxed Warnings for Aminoglycosides?

Causes severe ototoxicity (ear damage) and nephrotoxicity (kidney damage).

What are the age and pregnancy restrictions for Tetracyclines?

Contraindicated in pregnancy and children under 8 due to bone/tooth effects.

What mineral interactions affect Tetracyclines?

Calcium, iron, dairy, and antacids bind tetracyclines, blocking GI absorption.

What is the clinical role of Macrolides?

Protein synthesis inhibitors used as classic alternatives for penicillin-allergic patients.

What is the major risk associated with Clindamycin?

High risk of causing Clostridioides difficile pseudomembranous colitis (C-diff).

What is the drug class risk for Linezolid & Tedizolid?

Oxazolidinones act as MAO inhibitors; tyramine foods risk serotonin syndrome.

What are the Boxed Warnings for Fluoroquinolones?

Causes tendinitis, tendon rupture, peripheral neuropathy, and CNS toxicity.

What is the age cutoff for Fluoroquinolones?

Avoided in patients under age 18 due to risk of cartilage damage.

What are the anchor drugs for Antituberculosis treatment?

Isoniazid (INH) and rifampin, given in multi-drug regimens for 6+ months.

What is a notable side effect of Rifampin?

Harmlessly turns bodily fluids orange (urine, sweat, tears).

What is the mechanism of action of Trimethoprim-Sulfamethoxazole (Bactrim)?

Inhibits bacterial folic acid synthesis needed for nucleic acid production.

What is the pregnancy risk of Sulfonamides?

Contraindicated near term due to risk of severe infant kernicterus.

What cross-reactivity risks exist with Sulfonamides?

Allergies may cross-react with sulfonylurea antidiabetics and thiazide/loop diuretics.

How does a UTI typically present in older adults?

Often presents as acute confusion or altered mental status rather than dysuria.

Why are Antivirals hard to develop?

Viruses replicate inside human host cells without distinct targets.

What is the mechanism of action and administration window for Neuraminidase Inhibitors?

Inhibits viral release; must start within 48 hours of symptom onset.

What causes the adverse effects of Oseltamivir (Tamiflu)?

CNS side effects linked to altered dopamine levels in brain tissue.

What is the excretion route and safety profile of Acyclovir?

Excreted unchanged in urine; drug of choice for pediatric herpes infections.

Why are Cidofovir and Probenecid co-administered?

Probenecid reduces cidofovir uptake in renal tubules, protecting against nephrotoxicity.

What is the main side effect of Ganciclovir?

Causes bone marrow suppression requiring complete blood count monitoring.

What is the standard approach for HIV Pharmacotherapy?

Always treated with combination antiretroviral therapy; does not cure HIV.

What is the recommendation for maternal HIV and breastfeeding?

HIV-positive mothers should avoid breastfeeding to prevent vertical viral transmission.

What is the mechanism of action of Azole Antifungals?

Binds to ergosterol in fungal cell walls to disrupt structural integrity.

How do Ketoconazole and Fluconazole toxicity compare?

Ketoconazole causes endocrine disorders and LFT changes; fluconazole does not.

What is the target and route of administration for Echinocandins?

Inhibits glucan synthesis; administered IV-only for severe systemic fungal infections.

What is the clinical role and toxicity of Amphotericin B?

Reserved for life-threatening fungal infections due to severe nephrotoxicity and organ damage.

How is Nystatin administered for oral thrush?

Swish and swallow liquid; acts topically without systemic GI absorption.

What parasite and vector cause Malaria?

Caused by Plasmodium parasite transmitted through female Anopheles mosquito bites.

What are the symptoms of Cinchonism?

Quinine toxicity marked by nausea, vomiting, tinnitus, and vertigo.

What interaction occurs between Metronidazole and alcohol?

Causes severe disulfiram-like reaction; avoid alcohol during and 3 days post-treatment.

What reaction occurs when combining Metronidazole and Disulfiram?

Combining metronidazole with disulfiram (Antabuse) causes life-threatening psychotic reactions.

How is a Helminthic Infection diagnosed?

Requires stool examination for ova (eggs) and parasites.

What measures are required for Pinworm control?

Treat all household members, wash hands, and launder bed linens in hot water.

How is Trichinosis transmitted?

Caused by consuming raw or undercooked infected pork containing encysted larvae.

What is the safety warning for Ivermectin?

Toxic to infants; contraindicated in breastfeeding mothers and useless against viruses.

What are the three basic parts of a cell?

The nucleus, cell membrane, and cytoplasm.

How do DNA and RNA differ in cellular function?

DNA holds master instructions inside the nucleus; RNA carries working copies to cytoplasm.

What are Histocompatibility Antigens?

Surface proteins that mark a cell as 'self' so the immune system leaves it alone.

What happens when Lysosomes are released during tissue injury?

Dying cell lysosomes rupture and release digestive enzymes, damaging surrounding healthy tissue.

How do Hypertonic and Hypotonic Solutions differ in cellular effect?

Hypertonic solutions draw water out causing cell shrinkage; hypotonic solutions move water in causing swelling.

How does the Sodium-Potassium Pump function?

Active transport mechanism requiring ATP to keep potassium high and sodium low inside cells.

What are the five phases of the cell cycle?

G0 (resting), G1 (RNA/protein synthesis), S (DNA replication), G2 (spindle production), and M (mitosis).

How do Cancer Cells in G0 Phase evade chemotherapy?

Resting G0 cells evade chemo targeting active division, requiring repeated treatment cycles over time.