[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › Immunoglobulins and antitoxins

[Pharmacology](https://durgical.com/en/pharmacology/) · Class

# Immunoglobulins and antitoxins

Ready-made antibodies, human or equine, that give immediate but temporary protection against a toxin, a virus or an antigen.

Updated 2026-11-01

## What they are

Antibody products for passive immunisation: normal immunoglobulin (pooled from many donors), human hyperimmune immunoglobulins (tetanus, rabies, anti-D), equine antitoxins (diphtheria, botulism) and monoclonal antibodies (palivizumab, nirsevimab, anti-rabies).

## Mechanism of action

The administered antibodies bind their antigen at once: they neutralise free toxins and viruses or, with anti-D, clear fetal red cells before the mother mounts her own response. They create no memory: protection lasts as long as the antibodies remain, longer for human IgG than for animal protein.

Target: Foreign antigens (toxins, viruses) or the RhD antigen on red cells

## Key points

- Passive immunisation = immediate protection with no memory; vaccines (active) take weeks but leave memory. In tetanus and rabies both are given, at different sites.
- Antitoxins only neutralise free toxin; toxin already fixed to tissue is not reversed, so they are given without waiting for laboratory confirmation.
- Horse-derived products can cause early anaphylaxis and late serum sickness.
- Immunoglobulins can blunt the response to live vaccines (measles, mumps, rubella, varicella).
- Human IgG stays in the circulation far longer than animal-derived antibody.

## Drugs in this class

- [**Anti-D immunoglobulin (Rho(D))** Human IgG against the RhD antigen. In an RhD-negative mother it clears RhD-positive fetal red cells before she forms… RhD antigen on fetal red cells](https://durgical.com/en/pharmacology/anti-d-immunoglobulin/)
- [**Rabies immunoglobulin** Antibodies against rabies virus that are infiltrated into the wound after severe exposures, while the vaccine builds… Rabies virus glycoprotein G](https://durgical.com/en/pharmacology/rabies-immunoglobulin/)
- [**Human tetanus immunoglobulin** Human IgG against tetanus toxin. It neutralises toxin not yet bound to nerves in tetanus-prone wounds and in the… Free tetanospasmin (tetanus toxin)](https://durgical.com/en/pharmacology/human-tetanus-immunoglobulin/)
- [**Normal human immunoglobulin (IVIG)** IgG pooled from the plasma of thousands of donors. It replaces antibodies in immunodeficiency and modulates the immune… Broad repertoire of antigens and Fc receptors](https://durgical.com/en/pharmacology/normal-human-immunoglobulin/)
- [**Diphtheria antitoxin (equine)** Horse antibodies that neutralise circulating diphtheria toxin. Given with antibiotics on clinical suspicion, without… Circulating diphtheria toxin](https://durgical.com/en/pharmacology/diphtheria-antitoxin/)

## Others in the class

- Botulism antitoxin
- Equine rabies immunoglobulin
- Anti-rabies monoclonal antibodies
- Palivizumab
- Nirsevimab

## Test yourself

Think of the answer, then tap the question to see it.

## What is the main difference between passive and active immunisation?

Passive transfers ready-made antibodies: it protects at once but leaves no memory. Active (a vaccine) takes time to protect but builds lasting memory.

## Why must an antitoxin be given early?

It only neutralises toxin circulating freely; toxin already bound to nerves or tissues cannot be removed.

## Which late reaction is typical of horse antisera?

Serum sickness: immune complexes against the equine protein cause fever, urticaria, joint pain and lymph-node swelling days to weeks later.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/classes/immunoglobulins-and-antitoxins/)

[← All of pharmacology](https://durgical.com/en/pharmacology/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/) (World Health Organization, 2025); Farmacología básica y clínica (Katzung), ch. 55 (McGraw Hill, 2025); Farmacología básica y clínica (Katzung), appendix (vaccines and immune globulins) (McGraw Hill, 2025); [Immune Globulin Intravenous (Human)(IVIG): MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a624082.html) (MedlinePlus (U.S. National Library of Medicine), 2025).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/classes/immunoglobulins-and-antitoxins/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/classes/immunoglobulins-and-antitoxins/