Zanamivir

These indications are based on manufacturer information for both originator and generic products. For product specific registered indications, please refer to product specific manufacturer information

Registered South African indications:  

• Treatment and prophylaxis of Influenza A and B in adults and children (>5 years)

Contraindications

• Hypersensitivity to the active ingredient or any of its excipients
• Hypersensitivity to lactose or milk protein

Cautions

• Pregnancy
• Breastfeeding 
• Elderly
• Severe asthma or other chronic respiratory disease
• Immunocompromised patients
• Unstable chronic illnesses
• Administration as an extemporaneous solution by nebulisation or mechanical ventilation
• Illness caused by viruses other than influenza
• Galactose intolerance
• Lapp lactase deficiency
• Glucose-galactose malabsorption
• Neuropsychiatric events

Forms avail. in SA and covered in this monograph: inh

Treatment of influenza A and B

• Oral (inh): 10mg (2 inhalations), 12hrly; Treatment duration: 5 days

Treatment should begin as soon as possible, within 36hrs after onset of symptoms

Prevention of influenza A and B
- Post-exposure prophylaxis 

• Oral (inh): 10mg (2 inhalations), dly; Treatment duration: 10 days

- Seasonal prophylaxis, community outbreak 

• Oral (inh): 10mg (2 inhalations), dly; Treatment duration: 28 days

Treatment should begin as soon as possible, within 36hrs after onset of symptoms

 Initiate treatment within 5 days of an outbreak

Zanamivir is not a substitute for influenza vaccination

Not established for use in children below 5 years

Pregnancy

• Caution; not recommended
• Systemic exposure to zanamivir is low following administration by inhalation; however, there is no information on the placental transfer of zanamivir in humans
• There is a limited amount of data (less than 300 pregnancy outcomes) from the use of zanamivir in pregnant women
• Animal studies do not indicate direct or indirect harmful effects with respect to reproductive toxicity
• As a precautionary measure, it is preferable to avoid the use of zanamivir during pregnancy, unless the clinical condition of the woman is such that the potential benefit to the mother significantly outweighs the possible risk to the foetus 

Breastfeeding 

• Caution; not recommended 
• Systemic exposure to zanamivir is low following administration by inhalation; however there is no informatioon on the secretion of zanamivir into human breast milk
• A risk to the breastfed child cannot be excluded. A decision must be made whether to discontinue breastfeeding or to discontinue/abstain from zanamivir therapy, taking into account the benefit of breastfeeding the child and the benefit of therapy for the woman

Ferility

• Animal studies indicate no clinically meaningful effects of zanamivir on male or female fertility

Renal Impairment

• No dose adjustment recommended 

Hepatic Impairment

• No dose adjustment recommended

Elderly

• Caution; no dose adjustment recommended

Porphyria Information

• Not porphyrinogenic (NP)

Central Nervous System Disorders

• Seizures 
• Depressed level of consciousness
• Abnormal behaviour
• Hallucinations
• Delirium

Cardiovascular Disorders

• Vasovagal episodes

Respiratory Disorders

• Bronchospasm
• Dyspnoea
• Throat constriction

Endocrine and Metabolic Disorders

• Dehydration

Skin and Subcutaneous Tissue Disorders

• Facial oedema
• Rash
• Urticaria
• Erythema multiforme
• Stevens-Johnson syndrome
• Toxic epidermal necrolysis

Immune, Blood and Lymphatic System Disorders

• Allergic reactions
• Anaphylactic reactions 
• Anaphylactoid reactions
• Fever

No information available 

None routine. Specific cases may require 

• Respiratory examination

The use of antivirals for the treatment and prevention of influenza should take into consideration official recommendations, the variability of epidemiology, and the impact of the disease in different geographical areas and patient populations

The proposed mechanism of action of zanamivir is via inhibition of influenza virus neuraminidase with the possibility of alteration of virus particle aggregation and release. The drug renders the influenza virus unable to escape its host cell and infect others by binding and inhibiting the neuraminidase protein.

Inhalation powder (per blister) 5mg

• Relenza (GSK)