Type your drug name (like Atorvastatin, Sildenafil, etc)
Intron A
Specialty Drug
INTERFERON ALFA-2b is a man-made protein. Natural interferons are produced in the body to help the immune system fight viral infections and certain cancer growths. This medicine has similar actions to natural interferons and is used to treat AIDS-related Kaposi's sarcoma, certain types of hepatitis or certain cancers. This medicine may also be used to treat genital or perianal warts. Compare interferon alphas.
Prescription Settings
10 million IU
10 vials
Intron A(brand)
10 million IU
10 vials

Intron A Side Effects

What should I watch for?

Visit your doctor or health care professional for regular checks on your progress. You will need regular blood checks.

Do not change brands of this medicine without consulting your doctor or health care professional. Different brands of this medicine can act differently in your body. Check with your pharmacist if your refills do not look like your original product.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol can make you more drowsy or dizzy, increase confusion and lightheadedness. Avoid alcoholic drinks.

This medicine can cause flu-like symptoms and make you feel generally unwell. If you get a fever or sore throat that do not go away after the first few weeks of treatment, do not treat yourself. Report any of the above side effects, but continue your course of medicine even though you feel ill, unless your doctor or health care professional tells you to stop.

This medicine may decrease your body's ability to fight certain types of infections. This may be more of a concern if you are receiving high doses or other chemotherapy agents. Other signs of infection include lower back or side pain, pain or difficulty passing urine.

This medicine can cause blood problems or increase your risk to bruise or bleed. Call your doctor or health care professional if you notice any unusual bleeding. Be careful not to cut, bruise, or injure yourself because you may get an infection and bleed more than usual.


Common and Rare Side Effects

Along with its needed effects, a medicine 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:

More common


difficult or labored breathing

swelling or puffiness of the face

tightness in the chest

weight loss

Less common

Back, leg, or stomach pains

bleeding, tender, or enlarged gums

bloody, black, or tarry stools

bloody nose

bloody or cloudy urine

blurred vision

change in personality

changes in behavior

chest pain, discomfort, or heaviness


clay-colored stools

confusion as to time, place, or person


cough producing mucus

coughing or spitting up blood

dark urine

decreased urination


difficult or painful urination

dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position



fast, slow, pounding, irregular, or racing heartbeat or pulse

feeling, seeing, or hearing things that are not there

feeling that others are watching you or controlling your behavior

feeling that others can hear your thoughts




hearing loss

heavier menstrual periods

hives or rash

hoarseness or husky voice

inability to speak

increased thirst

increased urination



itching, pain, redness, or swelling of the skin

light-colored stools


loss of appetite

loss of consciousness

loss of hearing

lower back or side pain

metallic taste

muscle aches or cramps

nausea or vomiting

pale skin

passing of gas

pinpoint red spots on the skin


severe mood or mental changes

severe stomach pain with nausea and vomiting

slow speech


sores, ulcers, or white spots on the lips or tongue or inside the mouth

stiffness of the limbs

stomach cramps, tenderness, or discomfort

stomach pain, continuing

stomach upset


swelling around the eyes

swelling of the face, fingers, hands, ankles, feet, or lower legs

swollen, painful, or tender lymph glands in the neck, armpit, or groin

thoughts of hurting or killing oneself

trouble sleeping

unusual behavior

unusual bleeding or bruising

unusual tiredness or weakness

weight gain

yellowing of the eyes or skin

Some side effects 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

Acid or sour stomach

bleeding gums

blistering, crusting, irritation, itching, or reddening of the skin

body aches or pain

burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings

change in taste, or bad, unusual, or unpleasant (after) taste

cracked, dry, or scaly skin

hair loss or thinning of the hair

irritation in the mouth

joint pain

lack or loss of strength

loss of memory

muscle or bone pain

pain or tenderness around the eyes and cheekbones

poor concentration

problems with memory

redness and swelling of the gums

stuffy or runny nose

swollen joints

Less common

Abnormal ejaculation

absent, missed, or irregular menstrual periods

bleeding, burning, inflammation, itching, or pain at the injection site

bone deformity

burning, itching, and pain in the hairy areas, pus at the root of the hair

burning, numbness, pain, or tingling in all fingers except smallest finger

cold and clammy skin

decrease in height

decreased interest in sexual intercourse

degenerative disease of the joint

difficulty with moving or walking

discoloration of the skin

inability to have or keep an erection

increased clear or white vaginal discharge

increased sensitivity of the skin to sunlight

itching or pain of the genital area

leg cramps

longer menstrual periods

loss in sexual ability, desire, drive, or performance

multiple swollen and inflamed skin lesions

pain in the ankles or knees

pain in the ribs

pain, inflammation, or swelling in the calves, shoulders, or hands

painful, red lumps under the skin, mostly on the legs

pelvic pain

rash with flat lesions or small raised lesions on the skin

red or irritated eyes

redness or swelling in the arms or legs

redness, tenderness, itching, burning, or peeling of the skin

severe sunburn


skin rash, encrusted, scaly, and oozing small lumps under the skin

small lumps under the skin

soreness of the muscles

stopping of menstrual bleeding

swelling or redness in the joints

tanning or blue-gray discoloration of the skin

tearing of the eyes

underactive reflexes

unexpected menstrual bleeding

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

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