- Differential Diagnosis
Drug Information for Pharmalgen (ALK-Abello A S): Warnings
- Clinical Pharmacology 1
- Indications and Usage
- Adverse Reactions
- Dosage and Administration
- How Supplied
- PRINCIPAL DISPLAY PANEL
- External Links Related to Pharmalgen (ALK-Abello A S)
See additional warnings given in the box at the beginning of this insert.
Some patients are highly sensitive to Hymenoptera venoms and, for such patients, it must be anticipated that even a small skin test dose could result in a serious systemic reaction. Adequate means to treat such reactions must be immediately available, including the following equipment8: stethoscope and sphygmomanometer; tourniquets, syringes, hypodermic needles, and large-bore (14 gauge) needles; aqueous epinephrine HCl, 1:1000; oxygen, intravenous fluids, and the equipment for administering them; oral airway; diphenhydramine or similar antihistamine; aminophylline and corticosteroids for intravenous injection; vasopressor.
Patients are most at risk of serious systemic reactions:
- During skin testing and the build-up to maintenance dose, before tolerance of the extract is established. Do not begin immunotherapy without establishing the appropriate initial dose by skin testing (see Dosage and Administration), and do not inject the undiluted extract concentrate at any time unless tolerance has been demonstrated.
- When changing to a freshly-reconstituted extract; all extracts lose potency over time, and a fresh extract could have an effective potency that is substantially greater than that of the old extract. Reduce the dose by at least 50% when switching a patient to a freshly-reconstituted extract; this is particularly important when the previous extract was near its expiration date.
- When changing to an extract from a different manufacturer. Processing and source materials may differ markedly among manufacturers, and extracts from different manufacturers should not be considered interchangeable. Such changes should not be made without establishing the proper dosage by skin testing.
- If an error in dosage occurs, take care to properly prepare, label, store, and control all dilutions.
Observe the patient for at least 30 minutes after injection, and be alert for the signs of impending reaction. Make sure the patient understands that serious delayed reactions can occur later on, how to recognize them, and what to do if they occur.
Patients who are receiving beta-blocking medication are high-risk patients for immunotherapy, because systemic reactions to the extract may be more severe in such patients9, and because the beta-blocker may impair the ability to reverse the reaction10. In such patients, this risk should be carefully weighed before a decision to treat is reached.
Treatment with ACE-inhibitors should be stopped at least 24 hours prior to injection due to an increased risk of anaphylactic reaction based on inhibition of the angiotensin metabolism 12, 13, 14.
Do not inject this or any allergenic extract intravenously. Before injecting the extract subcutaneously, retract the plunger on the syringe slightly and verify that no blood enters the syringe. If it does, remove the syringe and repeat the procedure at a different site.
This and any allergenic extract should be temporarily withheld or its dosage reduced under any of these conditions11:
- When the patient has an unexpectedly severe local or any systemic reaction to the previous dose.
- If the patient is experiencing allergic symptoms such as rhinitis or asthma, or is ill with flu or infection accompanied by fever.
- If an unusually long time has passed since the previous injection.
Allergic patients differ widely in their sensitivity to this or any allergenic extract, and no single dosage regimen can be recommended for all patients. The treatment schedule described under Dosage and Administration, below, is suitable for the majority of patients, but is based on a rather rapid build-up to the maintenance dosage and will have to be adjusted for sensitive patients. Progression to the next higher dose requires tolerance of the previous one, and the regimen must be modified if any of the conditions described above occur. Such modifications should include weaker dilutions and smaller dosage increments.
- Drug Information Provided by National Library of Medicine (NLM).