Antibiotics: Types and Superinfections

• Antibiotics are ineffective against viral illnesses, exposing patients to drug risks without benefits if used.

Bactericidal vs. Bacteriostatic Agents

• Bactericidal agents: Directly kill bacteria at clinically achievable concentrations.
• Bacteriostatic agents: Inhibit bacterial growth, requiring host defenses for elimination.

Narrow vs. Broad Spectrum Antibiotics

• Narrow-spectrum antibiotics are active against few microorganisms and are preferred to avoid killing normal flora and reduce resistance emergence.
• Broad-spectrum antibiotics affect many microbes, killing more competing organisms and normal flora and, thus, can lead to resistance.

Superinfection Risks

• Superinfections are new infections during primary treatment, indicating drug resistance.
• They develop when antibiotics eliminate normal flora, allowing secondary infectious agents to thrive.

Reasons for Using Multiple Antibiotics

• Used for initial therapy of severe infections of unknown etiology, mixed infections, resistance prevention, decreased toxicity, and enhanced antibacterial action.

Penicillin MOA

• Penicillins weaken bacterial cell walls, causing rupture by excessive water intake, effective only in growing and dividing bacteria.
• They inhibit transpeptidases (essential for cell wall synthesis) and activate autolysins (bacterial enzymes that cleave cell wall bonds).

Penicillin Allergy

• Alternative antibiotics: Vancomycin, erythromycin, or clindamycin can be used for patients with a penicillin allergy.
• Avoid: All penicillin family members and cephalosporins if there's a severe reaction.

Penicillin Allergy: Care Prioritization

• Immediate reactions occur 2-30 minutes post-administration, mediated by IgE antibodies, causing anaphylaxis, requiring epinephrine and respiratory support, and 30 minutes observation.
• Accelerated reactions occur within 1-72 hours, mediated by IgE antibodies.
• Delayed reactions occur days to weeks after administration.

Cephalosporin Generations

• Cephalosporin generations differ in antimicrobial spectrum and beta-lactamase susceptibility, based on introduction order.
• First-generation cephalosporins like Cephalexin are highly active against gram-positive bacteria with low resistance to beta-lactamases and poor cerebrospinal fluid distribution.
• Second-generation cephalosporins like Cefoxitin have higher activity against gram-negative bacteria and beta-lactamase resistance but poor cerebrospinal fluid distribution.
• Third-generation cephalosporins like Cefotaxime have higher gram-negative activity, beta-lactamase resistance, and good cerebrospinal fluid distribution.
• Fourth-generation cephalosporins like Cefepime have highest gram-negative activity, beta-lactamase resistance, and good cerebrospinal fluid distribution.
• Fifth-generation cephalosporins like Ceftaroline have high gram-negative activity, beta-lactamase resistance, and good cerebrospinal fluid distribution.

Surgical Prophylaxis

• First-generation cephalosporins like cephalexin are expected for surgical prophylaxis.

Vancomycin: Adverse Effects

• Renal failure: Major toxicity, dose-related, increased with nephrotoxic drugs.
• Ototoxicity: Rarely reversible, increased by prolonged treatment, renal impairment, ototoxic drugs.
• Rapid infusion: Causes flushing, rash, pruritus, urticaria, tachycardia, hypotension due to histamine release; prevent by infusing over 60 minutes.

C. Diff Treatment

• Treat with oral vancomycin or metronidazole, vigorous fluid/electrolyte replacement, and discontinue tetracyclines/clindamycin.

Doxycycline

• Avoid in children under 8 due to tooth discoloration risk.
• Renal impairment patients should use instead of other tetracyclines, as it is hepatically cleared.
• Causes increased skin sensitivity to UV light.
• Avoid taking with calcium, iron, magnesium, aluminum, or zinc; separate by at least 2 hours.
• Take on an empty stomach with a full glass of water.

Tetracyclines: Pregnancy/Lifespan

• Infants: Avoid in children under 8 due to risk of tooth discoloration.
• Pregnant: Avoid because animal studies show fetal harm.
• Breastfeeding: Avoid
• Older Adults: May interact with drugs, including digoxin; check interactions.

Gentamicin Dosing

• Toxic to kidneys and inner ears; use caution with nephrotoxic/ototoxic drugs.
• Gentamicin is inactivated by direct chemical interaction with penicillins in same IV solution.

Gentamicin Peaks And Troughs

• Once-Daily Dosing: Measure trough levels before next dose; peak levels unnecessary.
• Divided Doses: Take peak levels 30 minutes after IM injection or 30-minute IV infusion completion; take trough levels just before next dose.

Sulfonamides: Education

• Check for allergies, G6PD deficiency, renal impairment, pregnancy status.
• Contraindicated for patients with hypersensitivity to sulfonamides and related drugs (thiazide diuretics, oral hypoglycemics).
• Avoid during breastfeeding, pregnancy (near term/first trimester), and in infants under 2 months.
• Renal impairment may cause significant hemolysis.

Sulfonamides: Adverse Reactions

• Infants: Under 2 months: Risk of kernicterus.
• Pregnant: May cause birth defects, especially in the first trimester.
• Breastfeeding: Avoid in infants under 2 months.
• Older adults: Possible severe reactions, including neutropenia, Stevens-Johnson syndrome, toxic epidermal necrolysis.

UTIs

• Uncomplicated UTIs in women of childbearing age, not associated with predisposing factors.
• Acute uncomplicated pyelonephritis: kidney infection with fever, chills, flank pain, dysuria, frequency, urgency, pyuria.
• Uncomplicated cystitis: Lower UTI by bacteria.
• Complicated UTIs: In males/females, linked to predisposing factors like stones, prostatic hypertrophy, or indwelling catheters

UTI Terms

• Prostatic hypertrophy: enlarged prostate
• Renal Calculi: Kidney stones
• Nephrocalcinosis: Calcium accumulation in kidneys
• Ureteric Stricture: Narrowed ureter

UTI treatments

• Acute Cystitis: Treat with trimethoprim/sulfamethoxazole, nitrofurantoin, or fosfomycin.

TST Testing

• A positive reaction indicates a local immune response in individuals with an intact immune system exposed.
• Read 48-72 hours post-injection, a positive reaction is confirmed by a hardness region around injection area.

Rifampin

• Patients should receive a physical examination / chest radiograph to exclude active disease.
• High-risk contacts, residents and staff of prisons/jails, nursing homes, hospitals, homeless shelters, residential facilities for patients with AIDS, immigrants from countries with high TB prevalence, staff of mycobacteriology labs.

Ciprofloxacin

• Side effects include GI reactions (N/V, diarrhea, abdominal pain) and CNS effects (dizziness, headache, confusion).
• It can cause candida infections of the pharynx/vagina, seizures (rarely), and confusion/psychosis/visual disturbances in older adults.
• Should not be taken with cationic compounds (antacids, iron, zinc salts, sucralfate, calcium supplements, milk) within 6 hours before or 2 hours after.

MRSA Antibiotics

• Treat with daptomycin (cubicin).

Fluoroquinolones

• Rare adverse effects include tendon rupture, achilles tendon, phototoxicity, severe sunburn and C. Diff infection.

Antifungal Monitoring

• Labs: Monitor potassium, serum creatinine, LFTs, and RFTs. Caspofungin can decrease tacrolimus.
• Adverse: Infusion reactions, nephrotoxicity, hypokalemia, hematologic effects, cardiac suppression, liver injury.

Tinea Infections

• Dermatophytes cause ringworm.

Tinea Infections: Types

• Tinea pedis: athlete's foot; treat topically
• Tinea corporis: ringworm of the body treat topically
• Tinea cruris: jock itch (groin);
• Tinea capitis is on the scalp, difficult to treat, oral works is needed.

Influenza Prevention

• Antiviral drugs include adamantanes (amantadine, rimantadine) and neuraminidase inhibitors (oseltamivir, zanamivir, peramivir), also endonuclease inhibitor- baloxavir marboxil.
• Adamantanes is the 1st influenza drugs
• Neuraminidase inhibitors are Active against both A and B

Antiviral Agents

• Herpes simplex viruses, varicella-zoster virus, cytomegalovirus infection, hepatitis C and B, Influenza, respiratory syncytial virus (RSV), COVID. are treated with antiviral agents

CD4 Count

• CD4+ T lymphocytes in the blood are crucial for the immune system.
• It is a major factor in deciding when to initiate ART and changes drugs if the regimen is failing.

Protease Inhibitors

• Adverse effects include hyperglycemia, lipodystrophy, hyperlipidemia, bleeding in hemophiliacs, elevated transaminases, and decreased cardiac conduction.
• Clinical symptoms: circumoral/extremity paresthesias, taste alterations, N/V, diarrhea, jaundice, weakness, or tiredness.

Herpes Virus

• Vesicles will appear on the perianal skin, labia, vagina, cervix, foreskin of the clitoris or the penis
• Symptoms include painful urination and watery discharge
• systemic symptoms with fever, headache, myalgia, large painful ulcer like sores
• Treatment available with acyclovir (zovirax), famciclovir (famvir), valacyclovir (valtrex)
• Recurrent infection can be treated every day or just when symptoms appear (episodic)

Treponema Pallidum (Syphilis)

• Primary: 1-4 weeks primary lesion called a chancre: hard, red, protruding, painless sore
• Secondary: 2-6 weeks with skin lesions / flu symptoms
• Tertiary: 5-40 years with infection of brain (neurosyphilis), which can cause senility, paralysis, and severe psychiatric symptoms

Antiseptics and Disinfectants

• Antiseptics: applied to living tissue and used are prophylatic
• Disinfectants: are applied to objects and are too harsh for application on living tissue

Atovaquone/Proguanil

• Atovaquone/proguanil combination is highly effective for malaria prophylaxis and treatment in chloroquine-resistant areas.
• Both drugs are active against erythrocytic and exoerythrocytic plasmodial forms, including strains resistant to chloroquine, mefloquine, and pyrimethamine/sulfadoxine.

Mercury and Vaccines

• MMR Myths: Thimerosal, a mercury-based preservative found in some vaccines, but isn't a cause of autism
• Thimerosal is being phased out of vaccines (due to concerns of mercury exposure)

Injection Administration Sites

• IM sites: Vastus lateralis for infants <12 months; deltoid for children ≥12 months.

Methotrexate and Supplements

• Folic acid helps methotrexate inhibiting the metabolism of folic acid

Cyclosporine

• Dietary considerations of Grapefruit juice; inhibits metabolism of cyclosporine and can raise cyclosporine levels by 50% to 200%

Antihistamines

• MOA wise, Histamine 1 blockers binds selectively to H1-histaminic receptors
• Histamine 1 antagonists do not block H2 receptors, or block the release of histamine from mast cells or basophils

Antihistamines

• Recommendations advise to only use when clearly necessary and only when the benefits of treatment outweigh the potential risks to the fetus.

Diphenhydramine

• High effects in sleepiness and anticholinergic effects (lack of muscle contractions, glandular secretions, and nerve signals), nonsedative CNS effects, Gl effects, respiratory depression, local tissue injury
• Dietary considerations to give with food to help Gl effects

Montelukast

• Patient education includes taking it without regard to meals
• The medication may be taken without regard to meals
• If taking granules, can be poured directly into the mouth, dissolved in about 5mL of cold or room temp fluids or soft foods, take at night to decrease nocturnal awakening

Montelukast: Side Effects

• Generally well tolerated
• Side effects include: Postmarketing reports suggested between singulair and neuropsychiatric effects, especially mood changes and suicidality, rare side effects

Inhaled Corticosteroids

• Education: Spacers help prevent bronchospasm with sudden intake
• Adverse effects include: Thrush and hoarseness, speaking difficulty
• The patient should rinse mouth with water and gargle after each administrations
• Long term use may promote bone loss, take lowest dose that controls symptoms, adequate intake of calcium and vitamin D, participate in weight-bearing exercise

Acute Asthma: Hospital Treatment

• Includes oxygen, systemic glucocorticoids, nebulized high-dose SABA, nebulized ipratropium.

Short vs. Long Acting Bronchodilators

• Short-acting uses PRN to abort ongoing attack and provide quick relief.
• Long-acting is used for patients who experience frequent attacks, dosing is a fixed schedule but is Not a first line therapy

Viral Cold Medications

• The OTC decongestants available: Phenylephrine, Pseudoephedrine, Naphazoline, Oxymetazoline, Tetrahydrozoline, Xylometazoline. - Guaifenesin increases respiratory secretions.
• Analgesic medicines are also used
• As well as antihistamines and caffeine

Seasonal Allergies

• antihistamines is More effective when taken prophylactically and less helpful when taken after symptoms appear

Guifenesin

• Guifenesin is a Drug that renders cough more productive by stimulating the flow of respiratory tract secretions, doses higher than those normally employed may be needed