Z

zafirlukast

za-fir-loo-kast

(Accolate)

Do not confuse Accolate with Accupril, Accutane, or Aclovate.

classification

PHARMACOTHERAPEUTIC: Leukotriene receptor antagonist. CLINICAL: Antiasthma (see p. 78C).

Action

Binds to leukotriene receptors, inhibiting bronchoconstriction due to sulfur dioxide, cold air, specific antigens (grass, cat dander, ragweed). Therapeutic Effect: Reduces airway edema, smooth muscle constriction; alters cellular activity associated with inflammatory process.

Pharmacokinetics

Rapidly absorbed after PO administration (food reduces absorption). Protein binding: 99%. Metabolized in liver. Primarily excreted in feces. Unknown if removed by hemodialysis. Half-life: 10 hrs.

Uses

Prophylaxis, chronic treatment of bronchial asthma in adults and children 5 yrs and older.

Precautions

Contraindications: Hepatic impairment. Cautions: Concomitant warfarin therapy.

 ​Lifespan considerations

Pregnancy/Lactation: Drug is distributed in breast milk. Do not administer to breastfeeding women. Pregnancy Category B. Children: Safety and efficacy not established in pts younger than 5 yrs. Elderly: No age-related precautions noted.

Interactions

DRUG: Erythromycin, theophylline may decrease concentration/effect. Aspirin may increase concentration/effect. Increases effect of warfarin (increases INR). HERBAL: None significant. FOOD: Food decreases bioavailability by 40%. LAB VALUES: None significant.

Availability (Rx)

Tablets: 10 mg, 20 mg.

Administration/handling

PO

• Give 1 hr before or 2 hrs after meals.

Indications/routes/dosage

Bronchial asthma

PO: ADULTS, ELDERLY, CHILDREN 12 YRS AND OLDER: 20 mg twice daily. CHILDREN 5–11 YRS: 10 mg twice daily.

Side effects

Frequent (13%): Headache. Occasional (3%): Nausea, diarrhea. Rare (Less Than 3%): Generalized pain, asthenia (loss of strength, energy), myalgia, fever, dyspepsia (heartburn, indigestion, epigastric pain), vomiting, dizziness.

Adverse effects/toxic reactions

Concurrent administration of inhaled corticosteroids increases risk of upper respiratory tract infection.

Nursing considerations

Baseline assessment

Obtain medication history. Assess serum hepatic function lab values.

Intervention/evaluation

Monitor rate, depth, rhythm, type of respiration; quality, rate of pulse. Assess lung sounds for rhonchi, wheezing, rales. Monitor serum hepatic function tests.

Patient/family teaching

• Increase fluid intake (decreases lung secretion viscosity). • Take as prescribed, even during symptom-free periods. • Do not use for acute asthma episodes. • Do not alter, stop other asthma medications. • Do not breastfeed. • Report nausea, jaundice, abdominal pain, flu-like symptoms, worsening of asthma.

zaleplon

zal-e-plon

(Sonata)

Do not confuse zaleplon with zolpidem.

classification

PHARMACOTHERAPEUTIC: Nonbenzodiazepine. (Schedule IV). CLINICAL: Hypnotic (see p. 149C).

Action

Enhances action of inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Therapeutic Effect: Induces sleep.

Pharmacokinetics

Rapidly, almost completely absorbed following PO administration. Protein binding: 45%–75%. Metabolized in liver. Primarily excreted in urine. Partially eliminated in feces. Half-life: 1 hr.

Uses

Short-term treatment of insomnia (7–10 days). Decreases sleep onset time (no effect on number of nocturnal awakenings, total sleep time).

Precautions

Contraindications: None known. Cautions: Mild to moderate hepatic impairment (avoid use in severe impairment), depression, history of drug dependence, elderly, compromised respiratory function, depression, risk for suicide.

 ​Lifespan considerations

Pregnancy/Lactation: Unknown if drug crosses placenta; distributed in breast milk. Pregnancy Category C. Children: Safety and efficacy not established. Elderly: May be more sensitive to zaleplon effects.

Interactions

DRUG: Alcohol, other CNS depressants may increase CNS depression. Cimetidine may increase concentration/effect. CYP3A4 inducers (e.g., carbamazepine, phenobarbital, phenytoin, rifampin) may decrease concentration. HERBAL: St. John’s wort may decrease levels/effect. Gotu kola, kava kava, St. John’s wort, valerian may increase CNS depression. FOOD: High-fat, heavy meals may delay onset of sleep by approximately 2 hrs. LAB VALUES: None significant.

Availability (Rx)

Capsules: 5 mg, 10 mg.

Administration/handling

PO

• Give immediately before bedtime. • Giving drug with or immediately after high-fat meal results in slower absorption. • Capsules may be emptied and mixed with food.

Indications/routes/dosage

Insomnia

PO: ADULTS: 10 mg at bedtime. Range: 5–20 mg. ELDERLY: 5 mg at bedtime. Maximum: 10 mg.

Dosage in hepatic impairment

Mild to moderate: 5 mg. Severe: Not recommended.

Side effects

Expected: Drowsiness, sedation, mild rebound insomnia (on first night after drug is discontinued). Frequent (28%–7%): Nausea, headache, myalgia, dizziness. Occasional (5%–3%): Abdominal pain, asthenia (loss of strength, energy), dyspepsia (heartburn, indigestion, epigastric pain), eye pain, paresthesia. Rare (2%): Tremor, amnesia, hyperacusis (acute sense of hearing), fever, dysmenorrhea.

Adverse effects/toxic reactions

May produce altered concentration/behavior changes, impaired memory. Taking medication while ambulating may result in hallucinations, impaired coordination, dizziness, light-headedness. Overdose results in drowsiness, confusion, diminished reflexes, coma.

Nursing considerations

Baseline assessment

Provide for safety; raise bed rails. Provide environment conducive to sleep (back rub, quiet environment, low lighting).

Intervention/evaluation

Assess sleep pattern.

Patient/family teaching

• Take right before bedtime or when in bed and not falling asleep. • Avoid tasks requiring alertness, motor skills until response to drug is established. • Do not exceed prescribed dosage. • Do not take with or immediately after a high-fat or heavy meal. • Rebound insomnia may occur when drug is discontinued after short-term therapy. • Avoid alcohol, other CNS depressants.

zanamivir

zan-am-i-veer

(Relenza)

classification

PHARMACOTHERAPEUTIC: Antiviral. CLINICAL: Anti-influenza (see p. 71C).

Action

Appears to inhibit influenza virus enzyme neuraminidase, essential for viral replication. Therapeutic Effect: Prevents viral release from infected cells.

Pharmacokinetics

Systemically absorbed, approximately 4%–17%. Protein binding: less than 10%. Not metabolized. Partially excreted unchanged in urine. Half-life: 2.5–5.1 hrs.

Uses

Treatment of uncomplicated acute illness due to influenza virus A and B in adults, children 7 yrs and older who have been symptomatic for less than 2 days. Prevention of influenza A and B in adults and children 5 yrs and older.

Precautions

Contraindications: None known. Cautions: COPD, asthma, severe renal/hepatic impairment.

 ​Lifespan considerations

Pregnancy/Lactation: Unknown if drug crosses placenta or is distributed in breast milk. Pregnancy Category C. Children: Safety and efficacy not established in those younger than 7 yrs. Elderly: No age-related precautions noted.

Interactions

DRUG: None significant. HERBAL: None significant. FOOD: None known. LAB VALUES: None significant.

Availability (Rx)

Powder for Inhalation: 5 mg/blister.

Administration/handling

Inhalation

• Instruct pt to use Diskhaler device provided, exhale completely; then, holding mouthpiece 1 inch away from lips, inhale and hold breath as long as possible before exhaling. • Rinse mouth with water immediately after inhalation (prevents mouth/throat dryness). • Store at room temperature.

Indications/routes/dosage

Treatment of influenza virus

Inhalation: ADULTS, ELDERLY, CHILDREN 7 YRS AND OLDER: 2 inhalations (one 5-mg blister per inhalation for total dose of 10 mg) twice daily (approximately 12 hrs apart) for 5 days.

Prevention of influenza virus

Inhalation: ADULTS, ELDERLY, CHILDREN 5 YRS AND OLDER: 2 inhalations (10 mg) once daily for duration of exposure period (10 days for household exposure, 28 days for community exposure).

Side effects

Occasional (3%–2%): Diarrhea, sinusitis, nausea, bronchitis, cough, dizziness, headache. Rare (Less Than 1.5%): Malaise, fatigue, fever, abdominal pain, myalgia, arthralgia, urticaria.

Adverse effects/toxic reactions

May produce neutropenia. Bronchospasm may occur in those with history of COPD, bronchial asthma.

Nursing considerations

Baseline assessment

Pts requiring an inhaled bronchodilator at same time as zanamivir should use the bronchodilator before zanamivir administration.

Intervention/evaluation

Provide assistance if dizziness occurs. Monitor daily pattern of bowel activity, stool consistency.

Patient/family teaching

• Follow manufacturer guidelines for use of delivery device. • Avoid contact with those who are at high risk for influenza. • Continue treatment for full 5-day course. • Doses should be evenly spaced. • In pts with respiratory disease, an inhaled bronchodilator should be readily available.

zidovudine

zye-doe-vue-deen

(Apo-Zidovudine , Novo-AZT , Retrovir)

BLACK BOX ALERT Neutropenia, severe anemia may occur. Lactic acidosis, severe hepatomegaly with steatosis (fatty liver), including fatalities, have occurred. Symptomatic myopathy, myositis associated with prolonged use.

Do not confuse Retrovir with acyclovir or ritonavir.

Fixed-combination(s)

Combivir: zidovudine/lamivudine (an antiviral): 300 mg/150 mg. Trizivir: zidovudine/lamivudine/abacavir (an antiviral): 300 mg/150 mg/300 mg.

classification

PHARMACOTHERAPEUTIC: Nucleoside reverse transcriptase inhibitors. CLINICAL: Antiviral (see pp. 71C, 118C).

Action

Interferes with viral RNA-dependent DNA polymerase, an enzyme necessary for viral HIV replication. Therapeutic Effect: Slows HIV replication, reducing progression of HIV infection.

Pharmacokinetics

Rapidly, completely absorbed from GI tract. Protein binding: 25%–38%. Metabolized in liver. Crosses blood-brain barrier and is widely distributed, including to CSF. Primarily excreted in urine. Minimal removal by hemodialysis. Half-life: 0.5–3 hrs (increased in renal impairment).

Uses

Treatment of HIV infection in combination with at least two other antiretroviral agents. Prevention of maternal/fetal HIV transmission. OFF-LABEL: Prophylaxis in health care workers at risk for acquiring HIV after occupational exposure.

Precautions

Contraindications: Life-threatening allergic reactions to zidovudine or its components. Cautions: Bone marrow compromise, renal/hepatic dysfunction, decreased hepatic blood flow.

 ​Lifespan considerations

Pregnancy/Lactation: Unknown if drug crosses placenta or is distributed in breast milk. Unknown if fetal harm or effects on fertility can occur. Pregnancy Category C. Children: No age-related precautions noted. Elderly: Information not available.

Interactions

DRUG: Bone marrow depressants, ganciclovir may increase myelosuppression. May be antagonistic with doxorubicin. Hematologic toxicities may occur with interferon alfa. HERBAL: None significant. FOOD: None known. LAB VALUES: May increase mean corpuscular volume (MCV).

Availability (Rx)

Capsules (Retrovir): 100 mg. Injection Solution (Retrovir): 10 mg/ml. Syrup (Retrovir): 50 mg/5 ml. Tablets: 300 mg.

Administration/handling

IV

Reconstitution • Must dilute before administration. • Remove calculated dose from vial and add to D₅W to provide concentration no greater than 4 mg/ml.

Rate of Administration • Infuse over 1 hr. May infuse over 30 min in neonates.

Storage • After dilution, IV solution is stable for 24 hrs at room temperature; 48 hrs if refrigerated. • Use within 8 hrs if stored at room temperature or 24 hrs if refrigerated to minimize potential for microbial-contaminated solution. • Do not use if solution is discolored or precipitate forms.

PO

• Keep capsules in cool, dry place. Protect from light. • Food, milk do not affect GI absorption. • Space doses evenly around the clock. • Pt should maintain an upright position when given medication to prevent esophageal ulceration.

IV incompatibility

None known.

IV compatibilities

Dexamethasone (Decadron), dobutamine (Dobutrex), dopamine (Intropin), heparin, lorazepam (Ativan), morphine, potassium chloride.

Indications/routes/dosage

HIV infection

PO: ADULTS, ELDERLY, CHILDREN OLDER THAN 12 YRS: 200 mg q8h or 300 mg q12h. CHILDREN 12 YRS AND YOUNGER: 160 mg/m²/dose (maximum: 200 mg)q8h or 240 mg/m² q12h (maximum: 300 mg). FULL-TERM NEONATES: 4 mg/kg/dose q12h. PREMATURE NEONATES: 2–4 mg/kg/dose q12h based on gestation at birth.

IV: ADULTS, ELDERLY, CHILDREN OLDER THAN 12 YRS: 1 mg/kg/dose q4h around the clock. CHILDREN 12 YRS AND YOUNGER: 120 mg/m²/dose q6h. Maximum: 160 mg/dose. FULL-TERM NEONATES: 3 mg/kg/dose q12h. PREMATURE NEONATES: 1.5–2.3 mg/kg/dose q12h based on gestation at birth.

Prevention of maternal/fetal HIV transmission

PO: ADULTS: 200 mg 3 times/day, or 300 mg 2 times/day. Begin at 14–34 wks’ gestation and continue until start of labor.

IV (During Labor and Delivery): 2 mg/kg loading dose, then IV infusion of 1 mg/kg/hr until umbilical cord clamped. NEONATAL: Begin 6–12 hrs after birth and continue for first 6 wks of life. Use IV route only until oral therapy can be administered.

PO: FULL-TERM INFANTS: 4 mg/kg/dose q12h (IV: 3 mg/kg/dose q12h). INFANTS 30–34 WKS’ GESTATION: 2 mg/kg/dose q12h; increase to 3 mg/kg/dose at 2 wks of age (IV: 1.5 mg/kg/dose q12h; increase to 2.3 mg/kg/dose at 2 wks of age). INFANTS LESS THAN 30 WKS’ GESTATION: 2 mg/kg/dose q12h; increase to 3 mg/kg/dose at 4 wks of age (IV: 1.5 mg/kg/dose q12h; increase to 2.3 mg/kg/dose at 4 wks of age).

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