Beta2-agonists for the treatment of uterine contractions in anaphylaxis
Published online: November 9, 2020
Anaphylaxis is a potentially severe and life-threatening event that may involve the cutaneous, respiratory, gastrointestinal or cardiovascular systems. Uterine contractions are also recognized as a potential manifestation of anaphylaxis; however, this symptom is often neglected as a miscellaneous manifestation. Literature on the topic is limited, often focusing on the risk of preterm labor and fetal distress during pregnancy, rather than on the symptom of lower pelvic pain and its treatment.
In an article recently published in The Journal of Allergy and Clinical Immunology: In Practice, D’Astous-Gauthier et al. describe 2 cases of non-pregnant patients presenting with severe uterine cramping as the main manifestation of anaphylaxis. In both cases, intra-muscular epinephrine was found ineffective at relieving the symptom. In 1 case, high doses of salbutamol were used to treat subsequent reactions with success. The authors also present a systematic review of the literature on potential treatment options for uterine contractions during anaphylaxis. This systematic review identified 19 studies reporting on 31 cases of painful uterine contractions occurring during anaphylaxis or other events associated with mast cell activation. Uterine cramps were associated with systemic symptoms in 24 cases and lasted an average of 2.4 hours, but as long as 8 hours. Pre-treatment with antihistamines and montelukast generally failed to prevent recurrence, but non-steroidal anti-inflammatory drugs were used successfully in some reports.
Importantly, response to intramuscular epinephrine was found to be inconsistent in the literature. In ex vivo models, epinephrine is shown to paradoxically increase uterine contractions through its alpha-receptor activity. Selective activation of beta-receptor on the other hand has been shown to induce the relaxation of uterine smooth muscle. Consistent with this observation, a small number of cases reported clinical improvement of uterine cramping following administration of beta-2-agonists.
The authors conclude that there is a lack of quality data on painful uterine contractions occurring in the context of anaphylactic reactions and a need for clinical trials to determine the optimal management. In the meantime, in absence of other indications for epinephrine, current evidence suggests that beta-2 agonists and premedication with non-steroidal anti-inflammatory drugs could be the preferred options.
The Journal of Allergy and Clinical Immunology: In Practice, is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.