Generic Name

Zalcitabine

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Classification

FDA Approved Indications

• Treatment of HIV-1 infection in combination with other antiretroviral agents

Mechanism of Action

Zalcitabine is a nucleoside analog reverse transcriptase inhibitor that incorporates into viral DNA during replication, leading to chain termination and inhibition of HIV replication.

Dosage and Administration

Adult: Typically 0.75 mg orally every 8 hours, in combination with other antiretrovirals; dosage adjustments may be necessary based on renal function.

Pediatric: Dosing varies; consult specific pediatric guidelines.

Geriatric: Use with caution due to potential renal impairment.

Renal Impairment: Adjust dose based on degree of renal dysfunction, as the drug is primarily renally excreted.

Hepatic Impairment: No specific adjustment; use with caution.

Pharmacokinetics

Absorption: Well absorbed orally.

Distribution: Distributed widely; crosses blood-brain barrier.

Metabolism: Minimal hepatic metabolism.

Excretion: Primarily renal excretion of unchanged drug.

Half Life: Approximately 8 hours.

Contraindications

• Hypersensitivity to zalcitabine or any component of the formulation.

Precautions

• Use with caution in renal impairment, as accumulation may occur.
• Monitor for signs of peripheral neuropathy, pancreatitis, and lipoatrophy.
• Not recommended during pregnancy unless potential benefit outweighs risk; use effective contraception.

Adverse Reactions - Common

• Peripheral neuropathy (Common)
• Headache (Common)
• Lipoatrophy (Less common)

Adverse Reactions - Serious

• Pancreatitis (Serious (rare))
• Peripheral neuropathy leading to disability (Serious (rare))
• Myelosuppression, including anemia and granulocytopenia (Serious (rare))

Drug-Drug Interactions

• Other nephrotoxic or neurotoxic drugs
• Didanosine (increased risk of peripheral neuropathy)

Drug-Food Interactions

• None specifically known

Drug-Herb Interactions

• Limited data; avoid combining with St. John's Wort due to potential pharmacokinetic interactions

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed.
• Report symptoms of neuropathy, pancreatitis, unexplained weakness, or neurological changes.
• Maintain regular follow-up appointments.
• Avoid alcohol and toxic substances.

Special Considerations

Black Box Warnings:

• Lactic acidosis and severe hepatomegaly with steatosis—rare but serious risk associated with NRTIs including zalcitabine.

Genetic Factors: Limited data.

Lab Test Interference: May cause elevated amylase or lipase if pancreatitis develops.

Overdose Management

Signs/Symptoms: Severe peripheral neuropathy, pancreatitis, lactic acidosis, la hepatitis.

Treatment: Provide supportive care; hemodialysis may be considered to enhance drug elimination in overdose.

Storage and Handling

Storage: Store at room temperature 20-25°C (68-77°F).

Stability: Stable under recommended conditions; protect from excessive heat and moisture.