Usage
- Thymosin alpha 1 (thymalfasin) is primarily prescribed as an adjunct therapy for chronic hepatitis B and C in patients with compensated liver disease. It is also used in the treatment of various cancers (e.g., hepatocellular carcinoma, non-small cell lung cancer, malignant melanoma) and as an immune booster for conditions like HIV/AIDS, cystic fibrosis, and DiGeorge’s syndrome, and as an adjunct to boost response to vaccines. It may also be used to block steroid-induced apoptosis of thymocytes and support geriatric immune function, as well as for other conditions requiring immunomodulation.
- Pharmacological Classification: Immunomodulatory agent.
- Mechanism of Action: Thymosin alpha 1 acts by modulating and enhancing the immune system’s response. It promotes T-cell maturation and differentiation, enhances cytokine production (e.g., interferon-gamma), and increases natural killer (NK) cell activity.
Alternate Names
- Thymalfasin
- Brand Names: Zadaxin, Immunocin Alpha Plus, Imualfa
How It Works
- Pharmacodynamics: Thymosin alpha 1 primarily affects the immune system. It enhances cell-mediated immunity by promoting the maturation and differentiation of T lymphocytes. It stimulates the production of cytokines like interferon-gamma, interleukin-2, and interleukin-12, which further amplify the immune response. Increased NK cell cytotoxic activity is also observed.
- Pharmacokinetics: Administered subcutaneously, thymosin alpha 1 is absorbed rapidly, reaching peak serum levels within 1-2 hours. It has a short half-life of approximately 2 hours. It is metabolized and excreted primarily via renal pathways, with 31-60% of the dose excreted in urine.
- Mode of Action: Thymosin alpha 1 binds to specific receptors on the surface of lymphocytes, triggering intracellular signaling cascades that lead to enhanced T-cell function and cytokine production. The precise receptor and detailed downstream signaling pathways are still under investigation.
- Elimination Pathways: Primarily renal excretion with some hepatic metabolism.
Dosage
Standard Dosage
Adults:
- 1.6 mg subcutaneously twice weekly for 6-12 months for chronic hepatitis B. Alternative dosing regimens include 1.5 mg subcutaneously every third day. Dosages may range from 0.8-6.4 mg for single doses, and 1.6-16 mg daily for 5-7 days for multiple doses.
- For patients <40 kg: 40 mcg/kg twice weekly.
Children:
- Safety and efficacy have not been established in patients below the age of 18 years.
Special Cases:
- Elderly Patients: Use with caution; no specific dosage adjustment recommendations.
- Patients with Renal Impairment: Use with caution; dosage adjustments may be needed.
- Patients with Hepatic Dysfunction: Use with caution in decompensated liver disease; monitor liver function tests. May continue therapy unless signs of liver failure occur.
- Patients with Comorbid Conditions: Use with caution in autoimmune disorders; potential for exacerbation.
Clinical Use Cases
- Intubation, Surgical Procedures, Mechanical Ventilation, ICU Use, Emergency Situations: No specific dosing guidelines provided in source material. Dosage must be determined by healthcare provider.
Dosage Adjustments:
- Adjust dosage based on patient weight, renal and hepatic function, and response to therapy.
Side Effects
Common Side Effects:
- Local injection site reactions (redness, discomfort, pain)
Rare but Serious Side Effects:
- Erythema, transient muscle atrophy, polyarthralgia, hand edema, rash, allergic reactions (itching, rash, difficulty breathing), increased ALT levels
Long-Term Effects:
Adverse Drug Reactions (ADR):
- Severe allergic reactions (anaphylaxis), significant liver dysfunction
Contraindications
- Hypersensitivity to thymosin alpha 1
- Immunosuppressed patients (e.g., organ transplant recipients) unless benefits outweigh risks
- Pregnancy and breastfeeding (use caution)
Drug Interactions
- Limited data available; caution advised with other immunomodulating agents. Do not mix in same syringe with other medications.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: C (animal studies have not demonstrated adverse effects, but no adequate human studies). Avoid unless clearly needed.
- Breastfeeding: Unknown if excreted in breast milk; use caution.
Drug Profile Summary
- Mechanism of Action: Enhances T-cell function, cytokine production, and NK cell activity.
- Side Effects: Primarily injection site reactions; rare systemic effects.
- Contraindications: Hypersensitivity, immunosuppression, pregnancy (caution).
- Drug Interactions: Limited information, potential interactions with immunosuppressants.
- Pregnancy & Breastfeeding: Use with caution.
- Dosage: 1.6 mg SC twice weekly (chronic hepatitis B). Variations exist; see above.
- Monitoring Parameters: Liver function tests, HBeAg, HBsAg, HBV DNA, ALT.
Popular Combinations
- Interferon alpha for chronic hepatitis B and C
Precautions
- Monitor for hypersensitivity reactions, liver function abnormalities, and signs of infection. Pregnant/breastfeeding women should consult a doctor. Children: Safety and efficacy not established. Exercise caution in patients with autoimmune diseases.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Thymosin alpha?
A: For chronic hepatitis B in adults, 1.6 mg subcutaneously twice a week for 6-12 months is common. Alternative dosing regimens exist.
Q2: What are the common side effects?
A: Local injection site reactions (redness, pain, discomfort).
Q3: Is it safe to use during pregnancy?
A: Use with caution; only if clearly needed. Pregnancy Safety Category C.
Q4: How is Thymosin alpha 1 administered?
A: Subcutaneous injection.
Q5: What conditions is Thymosin alpha 1 used for?
A: Chronic hepatitis B and C, certain cancers, immune deficiencies, as an adjunct to improve response to vaccinations.
Q6: Are there any contraindications?
A: Hypersensitivity, immunosuppressed patients (except when benefits outweigh risks), pregnancy (with caution).
Q7: Does Thymosin alpha 1 interact with other medications?
A: Limited data available. Use with caution when co-administering with other immunomodulatory drugs.
Q8: How long should treatment with Thymosin alpha 1 last?
A: Treatment duration varies depending on the condition being treated. For chronic hepatitis B, 6-12 months is common.
Q9: What are the monitoring parameters during treatment?
A: Liver function tests (ALT, albumin, bilirubin), hepatitis B markers (HBeAg, HBsAg, HBV DNA), and ALT levels.
