Interferon alfa-2a Side Effects

Medically reviewed by Drugs.com. Last updated on Mar 23, 2023.

Applies to interferon alfa-2a: subcutaneous solution.

Serious side effects of Interferon alfa-2a

Along with its needed effects, interferon alfa-2a may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking interferon alfa-2a:

More common

• Blurred vision
• burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
• chest pain
• chills
• cough
• depression
• diarrhea
• discouragement
• dizziness
• dry skin
• fainting
• fast, slow, or irregular heartbeat
• feeling sad or empty
• fever or chills
• general feeling of discomfort or illness
• headache
• irritability
• itching
• joint pain
• lack of appetite
• loss of interest or pleasure
• muscle aches and pains
• nausea
• nervousness
• pounding in the ears
• rash
• runny nose
• shivering
• shortness of breath
• sneezing
• sore throat
• sweating
• thickening of bronchial secretions
• tightness in the chest
• tiredness
• trouble with concentrating
• trouble with sleeping
• troubled breathing
• unusual tiredness or weakness
• vomiting
• weight loss
• wheezing

Less common

• Back, leg, or stomach pains
• black, tarry stools
• bladder pain
• bleeding gums
• bloating
• bloody nose
• bloody or cloudy urine
• changes in skin color
• chest discomfort
• cold feeling
• collection of blood under the skin
• confusion
• constipation
• convulsions
• darkened urine
• deep, dark purple bruise
• difficult or labored breathing
• difficult, burning, or painful urination
• difficulty with breathing
• difficulty with moving
• dizziness, faintness, or lightheadedness when getting up from a lying or sitting position suddenly
• eye pain
• fear
• feeling cold
• feeling of constant movement of self or surroundings
• frequent urge to urinate
• general body swelling
• hair loss
• hoarseness or husky voice
• increased sweating
• indigestion
• itching, pain, redness, or swelling
• loss of bladder control
• lower back or side pain
• muscle cramps and stiffness
• muscle spasm or jerking of all extremities
• noisy breathing
• nosebleeds
• pain
• pain, swelling, or redness in the joints
• pain, tenderness, or swelling of the foot or leg
• pains in the stomach, side, or abdomen, possibly radiating to the back
• pale skin
• poor concentration
• redness, soreness, or itching skin
• sensation of spinning
• shaking
• sores, ulcers, or white spots on the lips or in the mouth
• sores, welting, or blisters
• stomach cramps
• stuffy nose
• sudden loss of consciousness
• swelling or inflammation of the mouth
• swollen or painful glands
• tenderness
• unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
• vomiting of blood or material that looks like coffee grounds
• watery or bloody diarrhea
• weakness in the arms or legs
• weight gain
• yellow eyes or skin

Rare

• Agitation
• bluish color of the fingernails, lips, skin, palms, or nail beds
• change in consciousness
• changes in the patterns and rhythms of speech
• coma
• dandruff
• decreased vision
• double vision
• drowsiness
• earache
• feeling of warmth
• generalized slowing of mental and physical activity
• inability to move the arms, legs, or facial muscles
• inability to speak
• lack of feeling or emotion
• light-colored stools
• loss of ability to use or understand speech or language
• loss of consciousness
• loss of memory
• oily skin
• pain or discomfort in the arms, jaw, back, or neck
• pain or tenderness around the eyes and cheekbones
• paleness or cold feeling in the fingertips and toes
• problems with memory
• problems with speech or speaking
• rapid, shallow breathing
• red, scaling, or crusted skin
• red, sore eyes
• redness of the face, neck, arms, and occasionally, upper chest
• restlessness
• seeing, hearing, or feeling things that are not there
• sensation of pins and needles
• shakiness and unsteady walk
• skin rash, encrusted, scaly, and oozing
• slow speech
• slurred speech
• stabbing pain
• stiff neck
• sudden sweating
• tingling or pain in the fingers or toes when exposed to cold
• trouble sitting still
• uncaring
• unsteadiness, trembling, or other problems with muscle control or coordination
• upper right abdominal pain

Incidence not known

• Blindness
• change in ability to see colors, especially blue or yellow
• coughing that sometimes produces a pink frothy sputum
• difficult, fast, or noisy breathing, sometimes with wheezing
• heavier menstrual periods
• migraine headache

Other side effects of Interferon alfa-2a

Some side effects of interferon alfa-2a may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

• Bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
• hair loss or thinning of the hair
• lack or loss of strength
• sleeplessness
• unable to sleep

Less common

• Abnormal ejaculation
• change in taste or bad unusual or unpleasant (after) taste
• decreased interest in sexual intercourse
• decreased sexual performance or desire
• excess air or gas in the stomach or intestines
• full feeling
• inability to have or keep an erection
• irregular menstrual period
• loss in sexual ability, desire, drive, or performance
• passing gas

For Healthcare Professionals

Applies to interferon alfa-2a: injectable powder for injection, injectable solution.

Psychiatric

Psychiatric side effects have included depression (16% to 28%) and suicidal behavior including suicidal ideation, suicide attempts, and suicides. Irritability (15%), insomnia (14%), anxiety (5% to 6%), and behavioral disturbances (3%) have also been reported. In a study of patients (n=25) with chronic myelogenous leukemia conducted to evaluate the neuropsychological symptoms related to the treatment with interferon alfa, a disproportionate number of these patients scored in the impaired range on tests of verbal memory, delayed visual memory, verbal fluency, visual scanning and sequencing, executive function, and motor dexterity for the preferred hand when compared to controls. Besides the mentioned cognitive deficits, the patients receiving interferon alfa also showed signs of personality and mood disturbances.^[Ref]

Depression has been reported to have sometimes continued after decreases in dosage or discontinuation of therapy.

Results of a recent study (n=14) of patients affected by chronic hepatitis C who received interferon alfa-2b suggests that the development of the interferon alfa-induced depressive symptoms may arise through depletion of central and peripheral 5-HT and reduction of tryptophan plasma levels.^[Ref]

Other

Other side effects have included flu like symptoms such as fatigue (58% to 95%), fever (25% to 92%), myalgia (68% to 71%), headache (44% to 66%), chills (23% to 64%), arthralgia/bone pain (25% to 47%), asthenia (6%), sweating (5%), leg cramps (3%), and malaise (1%). Weight loss (25% to 33%), change in taste or smell (3% to 25%), pain (24%), back pain (16%), night sweats (8%), menstrual irregularity (4%), reversible hearing loss, and tinnitus have also been reported.^[Ref]

Flu like symptoms may be especially prevalent during the first week of therapy.^[Ref]

Gastrointestinal

Gastrointestinal (GI) side effects have included anorexia (14% to 65%), diarrhea (20% to 42%), nausea/vomiting (33% to 39%), abdominal pain (12% to 15%), flatulence (3%), liver pain (3%), impaired digestion (2%), gingival bleeding (2%), and GI hemorrhage.^[Ref]

Nervous system

Most of the central nervous system adverse effects have been mild and reversible within a few days to 3 weeks after dose reduction or discontinuation of therapy.

A 49-year-old female with a history of chronic myeloid leukemia experienced myorhythmia coincident with interferon alfa-2a therapy. She was treated with increasing doses of subcutaneous interferon alfa-2a up to 6 megaunits daily, with good clinical and hematologic response. After 1.5 years on the interferon, she had a gradual onset of involuntary facial movements. Movements on her forehead and both sides of her lower face were noted by her family members. Brain magnetic resonance imaging (MRI) did not show any structural abnormality. The patient was asked to discontinue interferon. Within 2 weeks, she reported improvement of the facial movements, and at 1 month there was almost complete resolution of her symptoms.

A 44-year-old female with metastatic renal cell cancer experienced encephalopathy coincident with interferon alfa-2a therapy. She presented with progressive apathy and slight subjective memory loss as well as two seizures. Electroencephalogram showed multifocal epileptiform discharges. Lumbar puncture results were normal. MRI demonstrated hyperintensities in the basal ganglia and the adjacent white matter but no other significant lesions. After stopping interferon therapy, the patients clinical state normalized, as did MRI 3 weeks later.^[Ref]

Nervous system side effects have included headache (44% to 64%), dizziness (11% to 40%), decreased mental status (10% to 17%), paresthesias (7% to 12%), numbness (3% to 12%), sleep disturbances (10% to 11%), confusion (5% to 8%), involuntary movements (7%), lethargy (6%), sleep disturbances (5%), and impaired concentration (4%). At least one case of myorhythmia has also been reported, in addition to a case of encephalopathy.^[Ref]

Dermatologic

Dermatologic side effects have included skin rash (8% to 44%), injection site reaction (29%), diaphoresis (7% to 22%), partial alopecia (17% to 22%), dry skin (7% to 17%), pruritus (7% to 13%), hematoma (1%). Psoriasis, cutaneous eruptions, eczema, and seborrhea have also been reported in less than 1% of patients.^[Ref]

Respiratory

Respiratory side effects have included cough (19% to 27%), throat irritation (21%), coughing (16%), rhinorrhea (12%), dyspnea (8% to 12%), pneumonia (11%), sinusitis (greater than 1% to 11%), dryness or inflammation of the oropharynx (6%), epistaxis (4%), and rhinitis (3%).^[Ref]

Cardiovascular

Cardiovascular side effects have included hypertension (11%), edema (9% to 11%), chest pain (4% to 11%), dysrhythmia (7%), hypotension (4%), and arrhythmia (1%). Myocardial infarction has been reported rarely. Cases of cardiomyopathy have been reported rarely in patients treated with alpha interferons.^[Ref]

Ocular

Ocular side effects have included visual disturbance (5% to 6%) and conjunctivitis (4%).^[Ref]

Musculoskeletal

Musculoskeletal side effects have included arthritis or polyarthritis (5%).^[Ref]

Hepatic

Hepatic side effects have included transient increases of liver transaminase or alkaline phosphatase in up to 50% of studied patients diagnosed with chronic myelogenous leukemia receiving interferon alfa-2a. Other hepatic side effects rarely reported have included pancreatitis, hypertriglyceridemia, and hepatitis.^[Ref]

Severe chronic active hepatitis has been reported in a patient post completion of interferon alfa-2a therapy and successful treatment of chronic active hepatitis B.^[Ref]

Hematologic

The incidence of neutropenia (WHO grades III or IV) among chronic hepatitis C patients was over twice as high in those treated with 6 million international units thrice weekly (21%) as those treated with 3 million international units three times weekly (10%).^[Ref]

Hematologic side effects have included decreases in WBC (including neutropenia), hematocrit, and platelet counts.^[Ref]

Endocrine

Endocrine side effects have included thyroid disorders (hyperthyroidism or hypothyroidism).^[Ref]

Metabolic

Metabolic side effects have included hyperglycemia.^[Ref]

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

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