Canterbury DHB


ATG/ALG Guidelines

Horse antilymphocyte globulin has been shown to be superior to rabbit ALG. Prescribe it by the name of ATGAM to avoid confusion:

In This Section

Test Dose

Administration following test dose

Side Effects

Treatment of Side Effects

Administration and Monitoring

Contraindications of ALG/ATG Treatment

Test Dose

Test dose - Add approximately 0.5 mL (25 mg) Atgam® to 100 mL normal saline and infuse intravenously over one hour.

For monitoring details, see Administration and Monitoring below.

The purpose of the test dose is to see if the patient develops anaphylaxis. The signs of anaphylaxis are tingling in the extremities and around the mouth, swelling of the lips and larynx, bronchospasm, urgency of defecation, hypotension. It is rare in patients not previously exposed medically to animal protein but is obviously potentially fatal. During the test dose a doctor must be present throughout. Have adrenaline, chlorphenamine and hydrocortisone drawn up beforehand. The reaction will normally stop immediately with hydrocortisone 100 mg IV plus chlorphenamine IV but adrenaline may be necessary.

A severe systemic reaction or anaphylaxis to the test dose needs to be discussed with the consultant before proceeding with treatment. It may be necessary to discontinue treatment with this product.

Administration following test dose

Therapeutic dose – Add prescribed dose (40 mg/kg) of Atgam® to 500 to 1000 mL normal saline and infuse intravenously over 12 to 18 hours. See notes above.

Atgam® is ideally diluted down to a concentration of 1 mg/mL, but should not ever exceed a concentration of 4 mg/mL. Give it within 12 hours of being made up. Precede each daily dose of ALG/ATG with:

Side Effects

Immediate (During administration)

Late (after administration = serum sickness)

Onset is 7 to 13 days after starting ALG/ATG.

Very rarely

Treatment of Side Effects

In cases of immediate reactions hydrocortisone and antihistamines can be given as required.

Immediate allergic side effects usually respond to an extra dose of hydrocortisone and chlorphenamine. Pethidine 12.5 to 50 mg IV is also useful for severe reactions. Consider adding paracetamol if fever and chills persist.

Pyrexia during ALG/ATG may also be due to infection, so in neutropenic patients broad spectrum IV antibiotics (as per departmental protocol for neutropenic patients) must be commenced after obtaining blood cultures and appropriate peripheral swabs.

Treat fluid retention promptly with IV frusemide as response to oral diuretics is usually poor, and review fluid balance later the same day. If patient is hypertensive, treat associated fluid retention as above, and use nifedipine. For anaphylaxis discontinue ALG/ATG immediately and treat anaphylaxis appropriately.

If bleeding occurs during ALG/ATG, stop the infusion and give platelets. Resume when bleeding resolved. Also check coagulation screen.

For a rash reaction give hydrocortisone and chlorphenamine 6 hourly. If the rash persists, add ranitidine 150 mg twice daily, give regularly for the duration of the treatment.

If serum sickness develops, stop tailing prednisone and increase dose if necessary after discussion with consultant.

Administration and Monitoring


Contraindications of ALG/ATG Treatment

About this Canterbury DHB document (27305):

Document Owner:

Not assigned (see Who's Who)

Last Reviewed:

November 2019

Next Review:

November 2022


Note: Only the electronic version is controlled. Once printed, this is no longer a controlled document. Disclaimer

Topic Code: 27305