Pharmacy Dosage Calculations Final Exam

Dosage Calculations

• Heparin math and weight-based reconstitution are important concepts in dosage calculations.

Antibiotic Therapy

• Broad-spectrum antibiotics are effective against both gram-positive and gram-negative bacteria.
• Examples of broad-spectrum antibiotics include tetracycline and cephalosporins.
• These antibiotics are frequently used when the offending microorganism has not been identified yet by culture and sensitivity.
• Narrow-spectrum antibiotics are primarily effective against one type of bacteria.
• Examples of narrow-spectrum antibiotics include penicillin and erythromycin.
• The goal of antibiotic therapy is to "match the drug to the bug".
• Host factors such as age, pregnancy, allergy, and morbidity must be considered when selecting an antibiotic.
• Bactericidal antibiotics are directly lethal to bacteria at clinically achievable concentrations.
• Bacteriostatic antibiotics slow microbial growth but do not directly cause cell death.
• Superinfections can occur when broad-spectrum agents kill off normal flora, allowing opportunistic pathogens to take over.

Antibiotic Side Effects

• Allergic reactions can occur, including hypersensitivity, rash, pruritus, hives, and anaphylactic shock.
• Superinfections can occur as a result of antibiotic therapy.
• Organ toxicity can occur, affecting the ears, liver, kidneys, mouth, skin, respiratory, and GI systems.

TB Drugs

• Two phases of treatment: induction phase (2 months) and continuation phase (longer duration).
• Induction phase drugs include isoniazid, rifampin, ethambutol, and pyrazinamide.
• Continuation phase drugs include isoniazid and rifampin.
• Multiple drugs are used in combination to treat more resistant cases.
• Direct observation therapy (DOT) is used to ensure compliance with TB treatment.

Isoniazid (INH)

• Used in combination with another agent for induction phase.
• Used alone for continuation phase.
• Adverse effects include peripheral neuropathy, hepatotoxicity, optic neuritis, and anemia.

Rifampin (Rifadin)

• Broad-spectrum antibiotic effective against TB, leprosy, H flu, Staph, and Legionella.
• Prophylaxis use.
• Adverse effects include hepatitis, discoloration of body fluids (orange), and increased levels of P450 enzymes.

Pyrazinamide

• Unknown mechanism of bacterial kill.
• Adverse effects include hepatotoxicity, hyperuricemia, arthralgia, and GI disturbances.

Ethambutol (Myambutol)

• Bacteriostatic antibiotic.
• Used in combination with other drugs for TB treatment.
• Adverse effects include optic neuritis, allergy, and hyperuricemia.
• Active against all strains of MT.

Antifungal

• Two major groups: systemic mycotic infections and superficial mycotic infections.
• Systemic mycotic infections include opportunistic candidiasis and aspergillosis.
• Superficial mycotic infections include candidiasis and dermatophytes.

Amphotericin B

• Broad-spectrum fungal agent effective against systemic infections.
• Destroys cell wall and attacks sterols.
• Highly toxic, with potential infusion reactions, nephrotoxicity, and hypokalemia.

Flucytosine/Ancobon

• Combines with amphotericin B for increased effectiveness.
• Converted to anti-metabolite after uptake by the fungi.
• Adverse effects include hematological effects and bone marrow suppression.

Mechanism of Action for Anti-Viral

• Stop viral replication.
• Reverse transcriptase inhibitors, integrase inhibitors, and HIV infusion inhibitors prevent viral entry into the cell.
• Protease inhibitors prevent final maturation and release of viral particles.
• Combination therapy decreases resistance and new meds have fewer side effects.

Flu Vaccines

• Oseltamivir/Tamiflu (A and B) stops viral replication, only works if given early.
• Effective if given within 2 days of symptoms appearing, with decreased effectiveness if given later.
• Adverse effects include N/V and others.