Z
zafirlukast
Brand Name(s): Accolate
Clinical Pharmacology:Mechanism of Action: An antiasthmatic that binds to leukotriene receptors, inhibiting bronchoconstriction due to sulfur dioxide, cold air, and specific antigens, such as grass, cat dander, and ragweed. Therapeutic Effect: Reduces airway edema and smooth muscle constriction; alters cellular activity associated with the inflammatory process.
Pharmacokinetics: Rapidly absorbed after PO administration (food reduces absorption). Protein binding: 99%. Extensively metabolized in the liver. Primarily excreted in feces. Unknown if removed by hemodialysis. Half-life: 10 hr.
Available Forms:
Indications and Dosages:
Unlabeled Uses: Exercise-induced bronchospasm
Contraindications: None known.
Side Effects
Serious Reactions
Patient/Family Education
Monitoring Parameters
• Observe the patient’s fingernails and lips for cyanosis, manifested as a blue or dusky color in light-skinned patients and a gray color in dark-skinned patients
Geriatric side effects at a glance:
U.S. Regulatory Considerations
zalcitabine
Brand Name(s): Hivid
Clinical Pharmacology:Mechanism of Action: A nucleoside reverse transcriptase inhibitor that inhibits viral DNA synthesis. Therapeutic Effect: Prevents replication of HIV-1.
Pharmacokinetics: Readily absorbed from the GI tract (absorption decreased by food). Protein binding: less than 4%. Undergoes phosphorylation intracellularly to the active metabolite. Primarily excreted in urine. Removed by hemodialysis. Half-life: 1-3 hr; metabolite, 2.6-10 hr (increased in impaired renal function).
Available Forms:
Indications and Dosages:| Creatinine Clearance | Dose |
|---|---|
| 10-40 ml/min | 0.75 mg q12h |
| less than 10 ml/min | 0.75 mg q24h |
Contraindications: Moderate or severe peripheral neuropathy
Side Effects
Occasional (10%-5%)
Diarrhea, abdominal pain, oral ulcers, cough, pruritus, myalgia, weight loss, nausea, vomiting
Serious Reactions
• Peripheral neuropathy (characterized by numbness, tingling, burning, and pain in the lower extremities) occurs in 17% to 31% of patients. These symptoms may be followed by sharp, shooting pain and progress to a severe, continuous, burning pain that may be irreversible if the drug is not discontinued in time.
Patient/Family Education
Monitoring Parameters
• Serum amylase and triglyceride concentrations in patients with history of elevated amylase, pancreatitis, ethanol abuse, or receiving parenteral nutrition
• Assess the patient for evidence of potentially fatal pancreatitis, including abdominal pain, nausea and vomiting, and increasing serum amylase and triglyceride levels. If the patient develops any of these signs or symptoms, particularly abdominal pain, withhold the drug.
Geriatric side effects at a glance:
U.S. Regulatory Considerations
zaleplon
Brand Name(s): Sonata
Clinical Pharmacology:Mechanism of Action: A nonbenzodiazepine that enhances the action of the inhibitory neurotransmitter gamma-aminobutyric acid. Therapeutic Effect: Induces sleep.
Pharmacokinetics: Rapidly and almost completely absorbed following PO administration. Protein binding: 60%. Metabolized in liver. Primarily excreted in urine. Partially eliminated in feces. Half-life: 1 hr.
Available Forms:
Indications and Dosages:
Contraindications: Severe hepatic impairment
Side Effects
Serious Reactions
• Taking the drug while up and about may result in adverse CNS effects, such as hallucinations, impaired coordination, dizziness, and light-headedness.
Special Considerations
• Because of the short half-life, agent best for problems with sleep latency, rather than duration of sleep or number of awakenings (e.g., shift workers)
Patient/Family Education
• Timing of administration: Immediately before bedtime or after the patient has gone to bed and has experienced difficulty falling asleep
Monitoring Parameters
Geriatric side effects at a glance:
Use with caution in older patients with: COPD; untreated sleep apnea
U.S. Regulatory Considerations
Other Uses in Geriatric Patient: Hypnotic
Side Effects:
Geriatric Considerations – Summary: Zaleplon is similar in efficacy and side-effect profile to a short-acting benzodiazepine. Zaleplon should be reserved for short-term use. Sedating antidepressants (e.g., trazodone) or eszopiclone are preferred for long-term management of sleep problems. Although this agent may cause falls, this has not been well studied. Because zaleplon is a substrate of CYP C3A, it should be used with caution, especially with drugs such as nefazodone, clarithromycin, or amiodarone. When initiating therapy, zaleplon should be titrated carefully to avoid oversedation. In addition, zaleplon has the potential to induce withdrawal symptoms (e.g., anxiety and/or agitation) when discontinued abruptly.zanamivir
Brand Name(s): Relenza
Clinical Pharmacology:Mechanism of Action: An antiviral that appears to inhibit the influenza virus enzyme neuraminidase, which is essential for viral replication. Therapeutic Effect: Prevents viral release from infected cells.
Pharmacokinetics: Systemically absorbed, approximately 4%-17%. Protein binding: Low. Not metabolized. Partially excreted unchanged in urine. Half-life: 1.6-5.1 hr.
Available Forms:
Indications and Dosages:Influenza virus: Inhalation 2 inhalations (one 5-mg blister per inhalation for a total dose of 10 mg) twice a day (approximately 12 hr apart) for 5 days.
Prevention of influenza virus: Inhalation 2 inhalations once a day for the duration of the exposure period.
Unlabeled Uses: Influenza prophylaxis
Contraindications: None known.
Side Effects
Serious Reactions
Patient/Family Education
• Influenza vaccine remains the best way to prevent influenza and use of zanamivir should not affect the evaluation of individuals for annual influenza vaccination
• Patients scheduled to use an inhaled bronchodilator at the same time as zanamivir should use their bronchodilator before taking zanamivir
Monitoring Parameters
Geriatric side effects at a glance:
U.S. Regulatory Considerations
zidovudine
Brand Name(s): Retrovir
Clinical Pharmacology:Mechanism of Action: A nucleoside reverse transcriptase inhibitor that interferes with viral RNA-dependent DNA polymerase, an enzyme necessary for viral HIV replication. Therapeutic Effect: Interferes with HIV replication, slowing the progression of HIV infection.
Pharmacokinetics: Rapidly and completely absorbed from the GI tract. Protein binding: 25%-38%. Undergoes first-pass metabolism in the liver. Crosses the blood-brain barrier and is widely distributed, including to cerebrospinal fluid (CSF). Primarily excreted in urine. Minimal removal by hemodialysis. Half-life: 0.8-1.2 hr (increased in impaired renal function).
Available Forms:
