Relenza Diskhaler (zanamivir)

No dosing information is available for this tab.

Zanamivir powder for inhalation is administered only by oral inhalation using the inhaler (Diskhaler(R)) provided by the manufacturer.

Zanamivir has been administered IV+, but a parenteral dosage form of the drug is not available in the US.

Zanamivir powder for inhalation mustnotbe used to prepare an extemporaneous solution and mustnotbe administered using a nebulizer or mechanical ventilator. (See Administration Precautions under Cautions.)

No dosing information is available for this tab.

Zanamivir not metabolized by and does not affect cytochrome P-450 (CYP) enzymes, including CYP1A1, 1A2, 2A6, 2C9, 2C19, 2D6, 2E1, or 3A4. Drug interactions with drugs that are substrates or inhibitors of these enzymes unlikely.

Zanamivir is not a substrate of P-glycoprotein (P-gp).

Zanamivir does not inhibit organic anion transporter (OAT) 1, OAT2, OAT3, OAT4, organic cation transporter (OCT) 1, OCT2, OCT3, or urate transporter (URAT) 1.

Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

Selected Antiviral Agents/Influenza Virus Vaccine Live

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: Amantadine,(1) oseltamivir,(2) rimantadine,(3) zanamivir,(4) and baloxavir,(5) may inactivate the intranasal live influenza virus vaccine, preventing the body from developing an immune response.

CLINICAL EFFECTS: Administration of amantadine,(1) oseltamivir,(2) rimantadine,(3) zanamivir,(4) and baloxavir,(5) may render the intranasal live influenza virus vaccine ineffective.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The US manufacturers of amantadine,(1) oseltamivir,(2) rimantadine,(3) zanamivir(4), baloxavir(5), and the intranasal live influenza virus vaccine(6) state that these agents should not be initiated within 2 weeks of the administration of the intranasal live influenza virus vaccine and that the vaccine should not be administered within 48 hours of the discontinuation of these agents. Inactivated influenza vaccine may be used at any time.(1)

DISCUSSION: Because antiviral drugs such as amantadine,(1) oseltamivir,(2) rimantadine,(3) zanamivir,(4) and baloxavir (5) inhibit the replication of live viruses, these agents may interfere with the efficacy of the intranasal live influenza virus vaccine.

There are no severe interactions for this drug.

There are no moderate interactions for this drug.

*History of hypersensitivity reaction to zanamivir or any ingredient in the formulation (e.g., milk protein contained in the lactose vehicle).

• Exacerbation of chronic obstructive pulmonary disease
• Severe persistent asthma

• Chronic obstructive pulmonary disease

• Acute cognitive impairment
• Delirium
• Hallucinations
• Seizure disorder

Adverse effects occurring in 1-3% or more of adults and children 12 years of age or older include diarrhea; nausea; vomiting; nasal signs and symptoms; bronchitis; sinusitis; cough; ear, nose, and throat infections; headache; and dizziness. Adverse effects occurring in up to 5% of children 5-12 years of age include ear, nose, and throat infections; vomiting; nausea; and diarrhea. Bronchospasm and allergic-like reactions, including oropharyngeal edema and serious rash, have been reported. Some adverse effects may be related to the lactose vehicle (contains milk proteins) used in the powder for oral inhalation formulation.

Less Frequent

• Arthralgia
• Sore throat

Rare or Very Rare

• Anaphylaxis
• Bronchospastic pulmonary disease
• Cardiac arrhythmia
• Delirium
• Dyspnea
• Erythema multiforme
• Pharyngeal edema
• Seizure disorder
• Skin rash
• Stevens-johnson syndrome
• Syncope
• Toxic epidermal necrolysis
• Urticaria

More Frequent

• Cough
• Dizziness
• Nasal congestion
• Sinusitis

Less Frequent

• Chills
• Fever
• Nausea

Rare or Very Rare

• Acute abdominal pain
• Agitation
• Behavioral disorders
• Facial edema
• Fatigue
• Hallucinations
• Malaise
• Myalgia
• Nightmares
• Symptoms of anxiety

No enhanced messaging available.

Safety and efficacy for treatment of influenza have not been established in children younger than 7 years of age. Some clinical studies evaluating zanamivir have included children 5-6 years of age+; however, there is some evidence that the drug is not as effective in these children as in older children and adults.

Safety and efficacy for prophylaxis of influenza have not been established in children younger than 5 years of age. Safety and efficacy in adolescents and children 5 years of age or older for prophylaxis of influenza are similar to adults.

Some young children may have suboptimal inspiratory flow rates through the drug delivery system (Diskhaler(R)). When considering use of zanamivir in pediatric patients, clinicians should carefully evaluate the ability of the child to use the inhaler.

Children should receive zanamivir only under adult supervision and with close attention to proper use of the inhaler. The supervising adult should be instructed on proper use of the inhaler.

Available data from published studies suggest that the use of zanamivir during pregnancy is not associated with an increased risk of birth defects or adverse maternal or fetal outcomes; however, these studies had several limitations (e.g., lack of specific analyses for zanamivir, possible exposure and outcome misclassifications, small sample sizes) which preclude a definitive assessment of the risk.

In animal reproduction studies, no adverse maternal or embryofetal effects were observed in rats or rabbits treated with IV zanamivir at dosages that resulted in systemic exposures approximately 300 times those in humans receiving 10 mg of the drug twice daily by oral inhalation.

Pregnant women are at increased risk for severe complications from influenza, which may lead to adverse pregnancy and/or fetal outcomes including maternal death, stillbirths, birth defects, preterm delivery, low birthweight, and small size for gestational age.

Oseltamivir is the preferred antiviral for the treatment of suspected or confirmed influenza or prevention of influenza in women who are pregnant or up to 2 weeks postpartum.

It is not known whether zanamivir is distributed into human milk, affects milk production, or has any effects on breast-fed infants. Zanamivir is distributed into milk in rats.

The benefits of breast-feeding and the importance of zanamivir to the woman should be considered along with potential adverse effects on the breast-fed child from the drug or from the underlying maternal condition.

Safety and efficacy for treatment of influenza in geriatric adults 65 years of age or older is similar to that reported in younger adults.

Safety and efficacy for prophylaxis of influenza in geriatric adults 65 years of age or older in household or community settings are similar to that reported in younger adults. Efficacy has not been established for prophylaxis of influenza in geriatric individuals in nursing home settings.

The possibility exists of greater sensitivity to the drug in some older individuals.

Some geriatric patients may need assistance with the drug delivery system (Diskhaler(R)).