July 30, 2016


Zadaxin Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 1/10/2016

Zadaxin thymosin alpha 1 (thymalfasin) Injection is an amino acid peptide used to treat hepatitis B. Many people taking Zadaxin do not experience side effects. Common side effects of Zadaxin include redness and discomfort at the injection site, muscle atrophy, multiple joint aches and pains, and swelling and rash of the hand.

The recommended dosage of Zadaxin is 1.6 mg (900 g/m2) twice a week for 6 to 12 months. Other drugs may interact with Zadaxin. Tell your doctor all medications you take. Do not reuse any syringes or needles. If you are pregnant only take Zadaxin if clearly needed. Exercise caution when taking Zadaxin while breastfeeding.

Our Zadaxin thymosin alpha 1 (thymalfasin) Injection Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is Prescribing information?

The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.

Zadaxin FDA Prescribing Information: Side Effects
(Adverse Reactions)


ZADAXIN (thymalfasin) is well tolerated. During clinical experience involving over 2000 individuals with various diseases distributed over all age groups, no clinically significant adverse reactions attributable to thymosin alpha 1 administration were reported (see table below).

  Disease Adverse Event Rate
Viral Infection Chronic hepatitis B Chronic hepatitis C Human immunodeficiency < 1% drug related adverse events for all indications
Cancer Non-small cell lung cancer Melanoma  
Vaccine adjuvant Hepatitis B vaccine Influenza vaccine
Immune disorders Autoimmune liver disease Primary immune deficiency

Adverse experiences have been infrequent and mild, consisting primarily of local discomfort at the injection site, and rare instances of erythema, transient muscle atrophy, polyarthralgia combined with hand edema, and rash.

Read the entire FDA prescribing information for Zadaxin (Thymalfasin)

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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