Tarantula Envenomation Medication

Updated: Jun 19, 2020
  • Author: Scott D Fell, DO; Chief Editor: Joe Alcock, MD, MS  more...
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Medication Summary

No existing medications are specific to treat tarantula injuries occurring in the United States. Medical therapy is directed mainly at symptom relief.

One species of the funnel web spider (Atrax robustus) of Australia produces highly toxic venom that is neurotoxic and potentially fatal. Antivenom specific to Atrax has been developed and is used in Australia.



Class Summary

Antihistamines prevent but do not reverse histamine-mediated responses, particularly in smooth muscle of the bronchi, GI tract, uterus, and blood vessels. They prevent histamine responses in sensory nerve endings. Antihistamines are commonly used for temporary relief of symptoms caused by allergic conditions.

Diphenhydramine (Benadryl)

Diphenhydramine competes with histamine for cell receptor sites on effector cells; it has anticholinergic (drying) and sedative adverse effects.

Cetirizine (Zyrtec)

Cetirizine forms a complex with histamine to block H1-receptor sites on target cells in the blood vessels, GI tract, and respiratory tract.



Class Summary

Corticosteroids modify the body's immune response to diverse stimuli. They suppress the migration of polymorphonuclear (PMN) leukocytes and reverse increased capillary permeability, reducing inflammatory processes. Corticosteroids can cause profound and varied metabolic effects.

Prednisone (Deltasone, Sterapred, Orasone)

Prednisone has potent antiinflammatory effects in disorders of many organ systems.


Ophthalmic agents

Class Summary

Ophthalmic agents are used for inflammatory conditions in which corticosteroids are indicated and risk of infection exists.

Neomycin/polymyxin B/bacitracin topical (Cortisporin)

Hydrocortisone suppresses the inflammatory response. Because it also may inhibit the body's defense mechanism against infection, a concomitant antimicrobial drug may be used, giving rationale for the combination. Anti-infective components are included to provide action against specific susceptible organisms.