INTERFERON,BETA-1A (Systemic)

Some commonly used brand names are:

In the U.S.?

• Avonex
• Rebif

In Canada?

• Avonex
• Rebif

Category

• Multiple sclerosis (MS) therapy agent
• Biological response modifier

Description

Interferon beta-1a (in-ter-FEER-onBAY-ta) is used to treat the relapsing forms of multiplesclerosis (MS). This medicine will not cure MS, but it may slow some disablingeffects and decrease the number of relapses of the disease.

Interferon beta-1a is also used to treat genital warts.

This medicine is available only with your doctor's prescription, in thefollowing dosage form(s):

Parenteral
• Injection (U.S. and Canada)

Before Using This Medicine

In deciding to use a medicine,the risks of taking the medicine must be weighed against the good it willdo. This is a decision you and your doctor will make. For interferon beta-1a,the following should be considered:

Allergies?Tell your doctor if you have ever had any unusual orallergic reaction to interferons or human albumin. Also tell your health careprofessional if you are allergic to any other substances, such as foods, preservatives,or dyes.

Pregnancy?Interferon beta-1a has not been studied in pregnantwomen. However, studies in animals have shown that interferon beta-1a maycause miscarriages. Be sure your doctor knows if you are pregnant or if youmay become pregnant.

Breast-feeding?It is not known whether interferon beta-1a passesinto breast milk. Because of the possibility of serious unwanted effects inthe nursing infant, it is important that you discuss the use of this medicinewith your doctor if you wish to breast-feed.

Children?Studies on this medicine have been done only in adultpatients, and there is no specific information comparing use of interferonbeta-1a in children with use in other age groups.

Older adults?Many medicines have not been studied specificallyin older people. Therefore, it may not be known whether they work exactlythe same way they do in younger adults. Although there is no specific informationcomparing use of interferon beta-1a in the elderly with use in other age groups,this medicine is not expected to cause different side effects or problemsin older people than it does in younger adults.

Other medicines?Although certain medicines should not be usedtogether at all, in other cases two different medicines may be used togethereven if an interaction might occur. In these cases, your doctor may want tochange the dose, or other precautions may be necessary. Tell your health careprofessional if you are taking any other prescription or nonprescription (over-the-counter[OTC]) medicine.

Other medical problems?The presence of other medicalproblems may affect the use of interferon beta-1a. Make sure you tell yourdoctor if you have any other medical problems, especially:

• Alcohol abuse or
• Higher concentration of a liver enzyme called SGPT
• Liver disease, active or in the past?This medicine should beused cautiously. You should tell your doctor if you have any of these conditions.If you start having symptoms of liver problems such as jaundice (yellow skinand eyes), tell your doctor right away; your medicine may need to be stopped.

• Heart disease?Some side effects of this medicine may be harmfulto patients with serious heart problems
• Mental depression or thoughts of suicide or
• Psychiatric disorders or
• Other mood disorders?This medicine may make the condition worse
• Seizure disorder?The risk of seizures may be increased

Proper Use of This Medicine

If you areinjecting this medicine yourself, use it exactly as directedby your doctor.

Special patient directions come with interferon beta-1a injection. Read the directions carefully before using the medicine.Make sure you understand:

• How to prepare the injection.
• Proper use of disposable syringes.
• How to give the injection.
• How long the injection is stable.

Dosing?If you are receiving interferonbeta-1a at home, follow your doctors orders or the directions on the label. If you have any questions about the proper dose of interferon beta-1a,ask your doctor.

• For injection dosage form:
  • For multiple sclerosis (MS):
    • Adults
      • For Avonex
        • 30 micrograms (mcg) once a week, injected into a muscle.
      • For Rebif
        • 22 micrograms (mcg) or 44 mcg 3 times a week, injected under theskin; your doctor may start you at a lower dose at first.
    • Children?Use and dose must be determined by the physician.
  • For genital warts:
    • Adults
      • For Rebif
        • 3.67 micrograms (mcg) per lesion 3 times a week for 3 weeks

Missed dose?If you miss a dose of this medicine, take it assoon as remembered. The next injection should be scheduled at least 48 hourslater.

Storage?To store this medicine:

• Keep out of the reach of children.
• Store away from direct light.
• Store prefilled syringes or vials of interferon beta-1a in the refrigerator.Do not freeze. If refrigeration is not available, the vials that have notbeen mixed with diluent may be kept for up to 30 days at room temperature,as long as the temperature does not go above 77 ?F.
• Do not keep outdated medicine or medicine no longer needed. Be surethat any discarded medicine is out of the reach of children.

Precautions While Using This Medicine

It isvery important that your doctor check your progress at regular visits to makesure that this medicine is working properly and to check for unwanted effects.

Importance of caretaker and/or patient informing doctor of any signs orsymptoms of depression or other mental or mood disturbances.

Check with your doctor right away if you experience dark urine, persistentloss of appetite, yellow eyes or skin, influenza (flu)-like symptoms, rightupper quadrant tenderness, headache, stomach pain, continuing vomiting, generalfeeling of tiredness or weakness, or light-colored stools. These could besymptoms of serious liver problems.

You should avoid alcohol while you are taking this medicine. It can causeserious liver problems.

This medicine commonly causes a flu-like reaction, with aching muscles,chills, fever, headache, joint pain, and nausea. Your doctor may ask you totake acetaminophen to help control these effects. Followyour doctor's instructions carefully about how much and when to take acetaminophen.

Side Effects of This Medicine

Along with its needed effects, a medicine maycause 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 as soon as possibleif any of the following side effects occur:

More common

Black, tarry stools; chest pain; chills; cough; diarrhea; fever; flu-likesymptoms including headache, joint pain, muscle aches, and nausea; pain; painful or difficult urination; shortness of breath; sores, ulcers, or white spots on lips or in mouth; swollen glands; unusual bleeding or bruising; unusual tiredness or weakness

Less common

Abdominal pain; chest pain; clumsiness or unsteadiness; convulsions(seizures); coughing; decreasedhearing; difficulty in swallowing; dizziness; fainting; flushing; hives or itching; moodchanges, especially with thoughts of suicide; musclespasms; pain or discharge from the vagina; pelvic discomfort, aching, or heaviness; redness, swelling, or tenderness at place of injection; runny or stuffy nose; skin lesions; sneezing; sore throat; speech problems; swelling of face, lips,or eyelids; troubled breathing; wheezing

Rare

Earache; general feeling of discomfortor illness; loss of appetite; painful blisters on trunk of body?also known as shingles; painful cold sores or blisters on lips, nose, eyes, or genitals

Incidence not known

Bleeding gums; blood in urine or stools; bloody nose; chest discomfort; confusion; constipation; continuing vomiting; convulsions; dark urine; decreased urine output; depressed mood; dilated neck veins; dry skin and hair; extreme fatigue; faintness; fast, irregular, or pounding heartbeat; feeling cold; general tiredness andweakness; hair loss; heaviermenstrual periods; high fever; hoarseness or husky voice; irregular breathing; light-colored stools; loss of bladdercontrol; mental depression; mood or other mental changes; muscle cramps and stiffness; muscle spasm or jerking of all extremities; nausea and vomiting; nervousness; pale skin; persistent anorexia; pinpoint red spots on skin; pruritus; puffiness or swelling of the eyelids, or aroundthe eyes, face, lips, or tongue; redness, blistering,peeling, or loosening of the skin; right upper quadranttenderness; sensitivity to heat; shortness of breath; skin rash; slowed heartbeat; stomach pain; sudden loss of consciousness; sweating; swelling of face, fingers, feet, or lower legs; swelling of the mouth or throat; tightnessin chest; tightness in throat; upper right abdominal pain; vesicular rash; weight gain; weight loss; yellow eyes and skin

Other side effects may occurthat usually do not need medical attention. These side effects may go awayduring treatment as your body adjusts to the medicine. However, check withyour doctor if any of the following side effects continue or are bothersome:

More common

Heartburn; indigestion; sour stomach

Less common

Hair loss; trouble in sleeping

Other side effects not listed abovemay also occur in some patients. If you notice any other effects, check withyour doctor.