Medications Exam 2

Question 1

Amoxicillin (Amoxil)
Classification: aminopenicillin

Answer 1

Antibacterial used to treat infections caused by susceptible organisms in the ears, nose, throat, genitourinary tract, skin, and structures.

Action: Binds to bacterial cell wall, causing cell death

Pharmacokinetics
Absorbed: from the duodenum (75-90%).
Distribution: Diffuses readily into most body tissues and fluids.
Metabolized/Excreted: 70% excreted in the urine, 30% metabolized by the liver

PO, Onset: 30 min; Peak: 1-2hr; Duration: 8-12 hr

Contraindication:
Hypersensitivity to penicillin; or allergic. Use cautiously with renal impairment.

Common Side Effects:
- GI upset
- Allergic reactions
- Rash

Interactions:
Aminoglycosides (IV) and clavulanic acid: Increased bacterial killing (additive effect)
* Methotrexate: Decreased renal elimination, leading to increased methotrexate levels
* NSAIDs: Compete for protein binding, potentially increasing free penicillin (may be beneficial)
* Oral contraceptives: Possible decreased contraceptive efficacy (mechanism uncertain)
* Probenecid: Competes for elimination, prolonging penicillin effects
* Rifampin: May inhibit penicillin’s bactericidal activity
* Warfarin: Enhanced anticoagulant effect due to reduced vitamin K from gut flora

Nursing Considerations:
- Complete full course of therapy
- Assess for allergic reactions (rash, anaphylaxis)
Additional info:
Amoxicillin can be combined with clavulanic acid (Augmentin), a beta-lactamase inhibitor

Question 2

Fluconazole (Diflucan)

Answer 2

Generic: fluconazole; Brand: Diflucan Class: Synthetic triazole antifungal

PO, IV/injectible

Indications:
Antifungal (thrush, yeast infections, ringworm, athlete’s foot)
-Fungal infections caused by susceptible organisms, including Oropharyngeal or esophageal candidiasis, Urinary Tract Infections, and Cryptococcal meningitis.
-Prevention of candidiasis in patients who have undergone bone marrow transplant
Effective for the treatment of vaginal candidiasis infections

Action: Inhibits synthesis of fungal sterols, a necessary component of the cell membrane.

Contraindications:
- Renal or hepatic dysfunction
- Drug allergy

Interactions:
-Increase risk of bleeding with warfarin
- Increase the risk of toxicity with antidepressants, losartan, amlodipine, felodipine, flurbiprofen, and more.

Common Side Effects:
- GI upset - nausea, vomiting, diarrhea, stomach pain
- Increased liver enzyme levels, dizziness

Nursing consideration:
- Monitor liver function
- Assess for improvement in symptoms of fungal infections
- Use with caution in patients with renal or hepatic dysfunction

Pharmacokinetics
Absorption: Well absorbed after oral administration
Distribution: Widely distributed; good penetration into the cerebrospinal fluid, saliva, sputum, vaginal fluid, skin, eye, and peritoneum
Metabolism & Excretion: Less than 80% excreted unchanged by the kidneys; Less than 10% metabolized by the liver.

PO; Onset of action: 1hr; Peak: 1-2hr; Duration: Variable

Question 3

Acyclovir (Zovirax):

Answer 3

Generic: acyclovir; Brand: Zovirax; Class: Antiherpevirus

PO, topical, and injectable

Indications:
Antiviral (Varicella aka chicken pox, Herpes virus)
-HSV-1 and HSV-2 infection, including genital herpes, mucocutaneous herpes, herpes encephalitis; herpes zoster (shingles); higher-dose therapy for acute episodes; and lower-dose therapy for viral suppression.

• Considered the drug of choice for the treatment of both initial and recurrent episodes of viral infections

Action:
A synthetic nucleoside analogue that is used to mainly suppress the replication of HSV-1, HSV-2, and VZV. - Interferes with viral DNA synthesis
Contraindications: Drug allergy, Renal impairment/failure

Side effects/adverse effects:
Nausea, diarrhea, headache, burning when topically applied

Contraindication:
- Drug allergy
- Renal impairment

Interaction:
interferon= Additive antiviral effects.
probenecid Increased acyclovir levels as a result of decreasing renal clearance.
Zidovudine Increased risk for neurotoxicity.

Nursing Consideration:
- Hydrate patient well
- Monitor kidney function
- Instruct patient to complete the full course

Pharmacokinetics
Absorption: Despite poor absorption (15-30%), therapeutic plasma concentration are achieved.
Distribution: Widely distributed. Cerebrospinal fluid concentrationare 50% of plasma
Metabolism and Excretion: Less than 90% eliminated unchanged by kidneys; remainder metabolized by liver.

PO- Onset: 1.2-2 hr; Peak: 1.5-2hr; Duration 10-15hr

Question 4

Digoxin