Indications
Interferon alfa-2a is an injectable medicine used for certain long-term viral infections and some cancers. Uses include chronic hepatitis B and hepatitis C (usually now replaced by newer tablets), hairy cell leukaemia, chronic myeloid leukaemia, certain lymphomas, Kaposi’s sarcoma, advanced kidney cancer and malignant melanoma.
How It Works
Interferons are proteins the body makes naturally to fight viruses. Interferon alfa-2a is a laboratory-made version. It switches on the body’s defences, making cells less able to let viruses multiply, slowing the growth of some cancer cells, and boosting the immune cells that attack infected or abnormal cells.
Dosage and Administration
Interferon alfa-2a is given as an injection under the skin or into a muscle. The dose, how often it is given and how long treatment lasts depend on the illness and are set by a specialist doctor; it is used as prescribed. The first injections are given or supervised by a doctor or nurse. Some patients are later taught to inject themselves at home.
Interactions
It can raise blood levels of Theophylline and some other medicines broken down by the liver. Using it with other drugs that suppress the bone marrow (such as Zidovudine or cancer medicines) increases the risk of low blood counts. Telbivudine should not be used with it because of nerve damage risk. Medicines that act on the brain, including sleeping pills and strong painkillers, may add to drowsiness or mood effects.
Contraindications
Not used in people with allergy to interferon alfa, severe heart disease, severe liver or kidney disease, decompensated cirrhosis, autoimmune hepatitis, a history of severe depression or suicidal thoughts, uncontrolled epilepsy, or uncontrolled thyroid disease.
Side Effects
Flu-like symptoms (fever, chills, muscle aches, headache, tiredness) are very common, especially at the start. Other effects include poor appetite, weight loss, nausea, diarrhoea, hair thinning, low blood counts, thyroid changes, low mood, irritability and trouble sleeping.
Get urgent medical help for thoughts of self-harm or severe depression, chest pain, irregular heartbeat, breathing problems, sudden vision changes, signs of infection with high fever, unusual bleeding or bruising, severe stomach pain, or yellow skin or eyes.
Pregnancy and Lactation
Interferon alfa-2a is generally avoided in pregnancy unless the specialist judges it essential. When it is combined with Ribavirin, pregnancy must be strictly avoided by women and the female partners of men during treatment and for several months after, as Ribavirin harms the unborn baby. Breastfeeding is not recommended during treatment.
Precautions and Warnings
Regular blood tests, liver and thyroid tests, and eye checks are needed. Mood should be watched closely by the patient, family and doctor. Drink plenty of fluids. Paracetamol taken as advised can ease flu-like symptoms. Tiredness may affect driving. Do not stop or change the dose without the doctor’s advice.
Overdose
Overdose may cause severe tiredness, drowsiness and other side effects. Contact a doctor or hospital; treatment is supportive and blood counts are checked.
Therapeutic Class
Immunomodulator, antiviral and antineoplastic (interferon).
Storage
Store in a refrigerator at 2 to 8°C, do not freeze. Keep in the original pack to protect from light. Keep out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.