Infergen Side Effects
Generic name: interferon alfacon-1
Note: This document provides detailed information about Infergen Side Effects associated with interferon alfacon-1. Some dosage forms listed on this page may not apply specifically to the brand name Infergen.
Applies to interferon alfacon-1: subcutaneous solution.
Important warnings
This medicine can cause some serious health issues
Subcutaneous route (solution)
May cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders.
Monitor closely and withdraw therapy with persistently severe or worsening signs or symptoms of the above disorders.
Use with ribavirin: Ribavirin may cause birth defects and fetal death; avoid pregnancy in female patients and in female partners of male patients.
Ribavirin causes hemolytic anemia, which may exacerbate cardiac disease.
Precautions
It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.
Using this medicine together with ribavirin while you are pregnant can harm your unborn baby. The medicine may also cause birth defects if the father is using it when his sexual partner becomes pregnant. If a pregnancy occurs while you are using this medicine, tell your doctor right away.
A negative pregnancy test is needed in women who are of childbearing age before starting combination treatment with interferon alfacon-1 (the active ingredient contained in Infergen) and ribavirin. Two forms of birth control must be used during treatment and for six months after treatment ends. You will need to have pregnancy tests done regularly to make sure you are not pregnant while being treated with these medicines and after your treatment ends.
This medicine commonly causes a flu-like reaction, with aching muscles, fever, chills, and headache. Using your shot at bedtime may allow you to sleep through the symptoms. Your doctor may want you to take a medicine for pain and fever (such as acetaminophen or ibuprofen) before or after each dose of interferon alfacon-1. Carefully follow your doctor's instructions about how to prevent or treat these symptoms.
This medicine may cause some people to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. If you or your caregiver notice any of these side effects, tell your doctor right away.
This medicine may lower the number of white blood cells in the blood. This will increase your chance of getting an infection. It can also lower the number of platelets in the blood. Platelets are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:
- If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
- Check with your doctor immediately if you notice any unusual bleeding or bruising; black, tarry stools; blood in the urine or stools; or pinpoint red spots on your skin.
- Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
- Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
- Be careful not to cut yourself when you are using sharp objects, such as a safety razor or fingernail or toenail cutters.
- Avoid contact sports or other situations where bruising or injury could occur.
This medicine may cause serious allergic reactions including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash; itching; hoarseness; trouble breathing; trouble swallowing; or any swelling of your hands, face, or mouth while you are using this medicine.
Stop using this medicine and check with your doctor right away if you have fever, stomach cramps, tenderness, pain, or watery or bloody diarrhea. These may be symptoms of a serious stomach problem called colitis.
Pancreatitis may occur while you are using this medicine. Tell your doctor right away if you have sudden and severe stomach pain, chills, constipation, nausea, vomiting, fever, or lightheadedness.
Check with your doctor immediately if blurred vision, difficulty in reading, or any other change in vision occurs during or after treatment. Your doctor may want you to have your eyes checked by an ophthalmologist (eye doctor).
Check with your doctor right away if you are having burning, numbness, tingling, or painful sensations in the arms, hands, legs, or feet. These could be symptoms of a condition called peripheral neuropathy.
Check with your doctor right away if you are having trouble breathing or if you experience a respiratory infection (such as pneumonia). This could result in a serious respiratory condition.
This medicine may cause high blood sugar levels. If you are diabetic and notice a change in the results of your blood or urine sugar tests, check with your doctor.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Serious side effects of Infergen
Along with its needed effects, interferon alfacon-1 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 alfacon-1:
More common side effects
- anxiety
- black, tarry stools
- blood in the urine or stools
- body aches or pain
- burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
- chest pain
- confusion
- congestion
- cough or hoarseness
- crying
- delusions
- dementia
- depersonalization
- depression
- diarrhea
- difficult or labored breathing
- dryness or soreness of the throat
- dysphoria
- euphoria
- feeling unusually cold
- fever or chills
- general feeling of discomfort or illness
- headache
- increased sweating
- joint pain
- loss of appetite
- lower back or side pain
- mental depression
- muscle aches and pains
- nausea
- nervousness
- painful or difficult urination
- paranoia
- pinpoint red spots on the skin
- quick to react or overreact emotionally
- rapidly changing moods
- redness at the place of injection
- runny nose
- shivering
- shortness of breath
- sore throat
- sweating
- tender, swollen glands in the neck
- tightness in the chest
- trouble with sleeping
- trouble with swallowing
- trouble with thinking or concentrating
- unusual bleeding or bruising
- unusual tiredness or weakness
- voice changes
- wheezing
Less common side effects
- irregular heartbeat
Rare side effects
- blurred vision or loss of vision
- skin rash, hives, or itching
Incidence not known
- abdominal or stomach pain
- bleeding gums
- bloody or black, tarry stools
- change in walking and balance
- clay-colored stools
- clumsiness or unsteadiness
- confusion
- constipation
- coughing up blood
- dark-colored urine
- decreased urination
- difficulty with breathing or swallowing
- dizziness
- dry mouth
- fainting
- fast heartbeat
- full or bloated feeling
- increase in heart rate
- increased menstrual flow or vaginal bleeding
- lightheadedness
- loss of consciousness
- muscle cramps or spasms
- nosebleeds
- paralysis
- pressure in the stomach
- prolonged bleeding from cuts
- rapid, shallow breathing
- red or black, tarry stools
- red or dark brown urine
- seizures
- severe stomach pain
- shakiness and unsteady walk
- shakiness in the legs, arms, hands, or feet
- sunken eyes
- swelling of the abdominal or stomach area
- thirst
- trembling or shaking of the hands or feet
- unpleasant breath odor
- unsteadiness, trembling, or other problems with muscle control or coordination
- vomiting of blood or material that looks like coffee grounds
- wrinkled skin
- yellow eyes or skin
Other side effects of Infergen
Some side effects of interferon alfacon-1 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 side effects
- acid or sour stomach
- aching muscles
- back pain
- belching
- decreased appetite
- difficulty with moving
- feeling of warmth
- general feeling of discomfort or illness
- hair loss
- heartburn or indigestion
- lack or loss of strength
- loss of memory
- muscle pain or stiffness
- pain in the back or joints
- pain in the limbs, muscles, or neck
- pain or tenderness around the eyes and cheekbones
- problems with memory
- redness of the face, neck, arms, and occasionally, upper chest
- sleeplessness
- stomach discomfort, upset, or pain
- stuffy nose
- sudden sweating
- swollen joints
- thinning of the hair
- unable to sleep
- weight loss
Incidence not known
- being forgetful
- 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
- blistering, peeling, or loosening of the skin
- bone pain
- burning feeling in the chest or stomach
- change in vision
- difficulty with moving
- difficulty with speaking
- false beliefs that cannot be changed by facts
- hearing loss
- pain, swelling, or redness in the joints
- red, irritated eyes
- red skin lesions, often with a purple center
- seeing, hearing, or feeling things that are not there
- sores, ulcers, or white spots in the mouth or on the lips
Interferon alfacon-1 may cause a temporary loss of some hair. After treatment has ended, normal hair growth should return.
For healthcare professionals
Applies to interferon alfacon-1: injectable solution.
General adverse events
A broad range of serious side effects have been reported with interferon alfacon-1 (the active ingredient contained in Infergen) alone or in combination with ribavirin. During clinical trials, more than 560 and 480 patients were exposed to monotherapy and combination therapy, respectively. In monotherapy studies, influenza-like symptoms (i.e., headache, fatigue, fever, rigors, myalgia, arthralgia, and increased sweating) were reported most often and depression was the most common side effect resulting in drug discontinuation. In the interferon alfacon-1 plus ribavirin combination therapy study, fatigue, nausea, influenza-like symptoms, headache, arthralgia, myalgia, neutropenia, leukopenia, insomnia, and depression were the most commonly reported side effects and fatigue, anemia, and depression were the most common side effects resulting in drug discontinuation. The most common serious adverse reactions reported with combination therapy were neutropenia, suicidal ideation, and hyperuricemia.[Ref]
Other
Other side effects have included fatigue (up to 77%), rigors (up to 66%), fever/pyrexia (up to 61%), body pain (up to 54%), influenza-like illness/symptoms (up to 42%), chest pain (up to 13%), malaise (up to 11%), asthenia (up to 10%), hot flushes, peripheral edema, access pain, earache, taste perversion, and otitis.[Ref]
Nervous system
Nervous system side effects have included headache (up to 82%), insomnia (up to 39%), dizziness (up to 25%), paresthesia (up to 13%), hypoesthesia (up to 10%), amnesia (up to 10%), hypertonia, somnolence, taste perversion, confusion, tinnitus, and hyperesthesia. Ischemic and hemorrhagic cerebrovascular events have been reported. Vestibular side effects associated with interferon alfacon-1 (the active ingredient contained in Infergen) have been mild and infrequent. Hearing loss, hearing impairment, speech disorder, ataxia, gait abnormal, convulsions, loss of consciousness, memory impairment, and tremors have been reported during postmarketing experience.[Ref]
Gastrointestinal
Gastrointestinal side effects have included nausea (up to 45%), abdominal pain (up to 41%), diarrhea (up to 29%), anorexia (up to 24%), dyspepsia (up to 21%), vomiting (up to 19%), decreased appetite (up to 18%), constipation (up to 10%), flatulence, toothache, decreased saliva output, ulcerative stomatitis, hemorrhoids, and gingivitis. Hemorrhagic/ischemic colitis (sometimes fatal) and pancreatitis (sometimes fatal) have been reported. Abdominal distention, gastrointestinal bleeding, and gastritis have been reported during postmarketing experience.[Ref]
Hematologic
Hematologic side effects have included leukopenia (up to 34%), neutropenia, thrombocytopenia, granulocytopenia, anemia, lymphocytosis, ecchymosis, lymphadenopathy, and increased prothrombin time. Decreases in hemoglobin (monotherapy: 4%; combination therapy: 88%), hematocrit (monotherapy: 5%), total white blood cell count, absolute neutrophil count (ANC), and platelet count have been reported. Hemolytic anemia (30%), ANC levels less than 0.75 x 10(9)/L (up to 27%), and lymphopenia (up to 14%) have been reported during combination therapy with ribavirin. Platelets decreased to less than 50 x 10(9) cells/L in 3% of patients during monotherapy and to less than 40 x 10(9)/L (but not less than 25 x 10(9)/L) in up to 3% of patients during combination therapy with ribavirin. Hemorrhage has been reported during postmarketing experience.[Ref]
Higher doses of interferon alfacon-1 were associated with a greater incidence of leukopenia and granulocytopenia and required dose reductions in 33% of patients receiving secondary therapy.
Decreases from baseline of 20% or more in hemoglobin or hematocrit were reported in less than or equal to 1% of patients during monotherapy trials. During the combination interferon alfacon-1 plus ribavirin trial, decreases in hemoglobin levels of greater than or equal to 2 g/dL from baseline were reported in 88% of patients. Of these, 27% had hemoglobin levels decrease to less than or equal to 10 g/dL, and underwent dose reductions of ribavirin.
By the end of initial monotherapy treatment, mean decreases from baseline of 19% for white blood cells (WBCs) and 23% for absolute neutrophil count (ANC) were reported. In patients subsequently retreated with monotherapy, mean decreases from baseline up to 23% for WBCs and up to 27% for ANC were reported.
Decreases in mean platelet count of 16% compared to baseline were observed by the end of monotherapy. Grade 4 thrombocytopenia was reported in one patient during the alfacon-1 plus ribavirin combination trial.[Ref]
Psychiatric
Psychiatric side effects have included nervousness (up to 31%), depression (up to 27%), irritability (up to 21%), abnormal thinking (up to 20%), anxiety (up to 19%), emotional lability (up to 12%), agitation, decreased libido, and apathy. Delusions and hallucinations have been reported during postmarketing experience.[Ref]
Depression was usually mild to moderate in severity in patients receiving interferon alfacon-1 therapy during clinical studies.[Ref]
Musculoskeletal
Musculoskeletal side effects have included myalgia (up to 58%), arthralgia (up to 51%), back pain (up to 42%), limb pain (up to 26%), skeletal pain (up to 14%), neck pain (up to 14%), and musculoskeletal disorder. Rhabdomyolysis, arthritis, and bone pain have been reported during postmarketing experience.
Cardiovascular
Cardiovascular side effects have included hypotension, arrhythmia, tachycardia, cardiomyopathy, angina pectoris, and myocardial infarction. Palpitation and hypertension have been reported. At least one case of irreversible pulmonary artery hypertension has been reported.[Ref]
A 36-year-old male with a history of intravenous drug use and alcoholism experienced irreversible pulmonary artery hypertension coincident with interferon alfacon-1 therapy. He was treated with interferon alfa-2a (3 million units/day) after he was found to have cirrhosis from Hepatitis C virus (HCV) and alcohol use. His viral load was 100,000 copies of stage IV fibrosis on liver biopsy. He was cleared of virus and received a liver transplant. Subsequently, he again became HCV positive (greater than 85,000 copies/mL) and was treated with interferon alfacon-1 (15 mcg/kg). Eight months into therapy, he developed progressive dyspnea on exertion, fatigue, and edema. He was found to have severe pulmonary hypertension on echocardiogram (PAP 81/30) with right heart failure. Other thromboembolic, inflammatory, and intrinsic cardiopulmonary causes were ruled out and interferon treatment was discontinued. He continues to experience severe refractory pulmonary hypertension.[Ref]
Ocular
Ocular side effects have included conjunctivitis, abnormal vision, and eye pain. Decrease or loss of vision, retinopathy (including macular edema, retinal artery or vein thrombosis, retinal hemorrhages, cotton wool spots), optic neuritis, papilledema, and serous retinal detachment have been induced or aggravated by treatment with interferon alfacon-1 (the active ingredient contained in Infergen) Retinal artery or vein obstruction has been reported rarely. Visual field defect has been reported during postmarketing experience.[Ref]
Immunologic
Immunologic side effects have included development of positive binding antibody responses (up to about 31%), development of low-titer neutralizing antibodies to interferon alfacon-1 (the active ingredient contained in Infergen) (up to 18%), and infection. Development or exacerbation of autoimmune disorders (e.g., autoimmune thrombocytopenia, idiopathic thrombocytopenia purpura, psoriasis, rheumatoid arthritis, thyroiditis, interstitial nephritis, systemic lupus erythematosus) has been reported. Sepsis has been reported during postmarketing experience.
Local
Local side effects have included injection site erythema (up to 23%), injection site reaction (up to 15%), pain, and ecchymosis. Injection site reaction, including injection site necrosis ulcer, and bruising have been reported during postmarketing experience.[Ref]
Metabolic
Metabolic side effects have included decreased weight (up to 22%), increased triglyceride levels (up to 7%), hypertriglyceridemia, hyperglycemia, and diabetes mellitus. Grade 4 uric acid levels (greater than 10 mg/dL) were reported in 49 patients during combination therapy with ribavirin. Dehydration has been reported during postmarketing experience.
Increases in serum triglyceride of 41% compared to baseline were observed at the end of monotherapy. During monotherapy treatment, 7% of patients developed values at least 3 times above pretreatment levels. Grade 3 or higher triglyceride elevations were reported in 2% of patients during the alfacon-1 plus ribavirin combination trial.
Serious adverse events related to elevated uric acid levels were reported in 4 patients during the alfacon-1 plus ribavirin combination trial.
Respiratory
Respiratory side effects have included pharyngitis (up to 34%), cough (up to 22%), dyspnea (up to 20%), sinusitis (up to 17%), upper respiratory infection, rhinitis, respiratory tract congestion, upper respiratory tract congestion, epistaxis, and bronchitis.
Dermatologic
Dermatologic side effects have included rash (up to 17%), pruritus (up to 15%), alopecia (up to 14%), increased sweating (up to 13%), erythema, dry skin, and wound. Bruising, pyoderma gangrenosum, and toxic epidermal necrolysis have been reported during postmarketing experience.
Endocrine
Endocrine side effects have included the occurrence or aggravation of hyperthyroidism or hypothyroidism. Abnormal thyroid function tests with increases in thyroid stimulating hormone (TSH) and decreases in thyroxine (T4) mean values have been reported. Increased TSH to greater than 7 mU/L was reported in 10% of patients treated with monotherapy during the treatment period or during the 24-week posttreatment period. During the interferon alfacon-1 (the active ingredient contained in Infergen) plus ribavirin combination trial, increased TSH levels were reported in up to 14% of patients at Week 12 and up to 54% at Week 48.[Ref]
Renal
Renal side effects have included increases in serum creatinine levels (including renal failure).
Hepatic
Hepatic side effects have included liver tenderness and hepatomegaly. Hepatic enzyme elevations (including ALT and AST elevations), abnormal hepatic function, hyperbilirubinemia, jaundice, ascites, and hepatic encephalopathy have been reported during postmarketing experience.[Ref]
Hypersensitivity
Hypersensitivity side effects have included allergic reactions. Urticaria, angioedema, bronchoconstriction, and anaphylaxis have been rarely reported.[Ref]
Genitourinary
Genitourinary side effects have included dysmenorrhea, vaginitis, menstrual disorder, menorrhagia, genital moniliasis, breast mass, and breast pain.
See also:
Epclusa
Epclusa treats chronic hepatitis C in adults and children 3+. This once-daily antiviral combines ...
Harvoni
Harvoni is used to treat hepatitis C virus (HCV) infections in adults and children aged 3 years and ...
Ozempic
Learn about Ozempic (semaglutide) for type 2 diabetes treatment, weight management, cardiovascular ...
Mavyret
Mavyret (glecaprevir/pibrentasvir) is an oral combination medicine containing fixed doses of two ...
Sovaldi
Sovaldi (sofosbuvir) is used to treat chronic hepatitis C virus (HCV) infection. Includes Sovaldi ...
Pegasys
Pegasys is used to treat chronic hepatitis B or C. Learn about side effects, interactions and ...
Vosevi
Vosevi (sofosbuvir,velpatasvir and voxilaprevir) is used to treat chronic hepatitis C. Includes ...
Glecaprevir/pibrentasvir
Glecaprevir/pibrentasvir (Mavyret) is an oral combination medicine containing fixed doses of 2 ...
Interferon alfa-2b
Interferon alfa-2b systemic is used for angioblastoma, condylomata acuminata, conjunctival ...
References
1. (2001) "Product Information. Infergen (interferon alfacon-1)." Amgen
2. Dhillon S, Baluch M, George M, Van Thiel DH (2003) "Irreversible pulmonary artery hypertension during interferon-alpha therapy for HCV infection: a case report." Am J Gastroenterol, 98(9S), S179-S180
3. Kleppinger EL, Ragan AP (2009) "Elevated hepatic transaminases associated with the use of interferon alfacon-1 and ribavirin." Am J Health Syst Pharm, 66, p. 465-8
More about Infergen (interferon alfacon-1)
- Check interactions
- Compare alternatives
- Dosage information
- During pregnancy
- Drug class: interferons
- Breastfeeding
Professional resources
Related treatment guides
Further information
Infergen side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.