Atgam ( Lymphocyte immunoglobulin antithymocyte) injection from Pfizer is used for ;
1. Prevention and treatment of acute renal allograft rejection
2. Prevention of graft-vs-host disease (GVHD) in bone marrow transplant (BMT) patients.
3. Treatment of aplastic anemia in patients not suitable for BMT.
Dose and Administration:
A test dose (0.1 mL of a freshly prepared 0.05 mg/mL solution in NS) may be given intradermally. The patient and injection site is examined every 15 min for one hr. However, a negative test does not guarantee a reaction-free administration. Also, a positive reaction does not always mean that the drug cannont be used with extreme caution if it is absolutely essential (risk/benefit analysis is necessary).
Before each dose, the patient may be pretreated with diphenhydramine (Benadryl) and acetaminophen (Tylenol).
The ATGAM dose must be diluted in normal saline or 1/2 normal saline to a concentration not exceeding 4 mg/mL. If the drug is to be given via a peripheral line (not recommended) the concentration should be less than 1 mg/mL.
The ATGAM dose should be administered via iv infusion into a central line over a minimum of 4 – 8 hrs. Infusion should be stopped immediately if a systemic reaction (dyspnea, tachycardia, hypotension, or a generalized skin reaction) or anaphylaxis occurs.
Acute Renal Allograft Rejection: 15 mg / kg q24h for 14 days, then give q48h for 7 more doses for a total of 21 doses in 28 days. Therapy should be discontinued if severe thrombocytopenia or leukopenia occurs.
Aplastic Anemia: 15 mg / kg q24h for 10 days, then give q48h for 7 more doses. Another protocol which is used only in adults calls simply for 40 mg/kg q24h for 4 days.
No pharmacokinetic drug interactions have been described.
Excessive immunosuppression can occur when used in combination with other immunosuppressive agents.