Topical nitroglycerin ointment as salvage therapy for peripheral tissue ischemia in newborns: a systematic review

BACKGROUND: Topical nitroglycerin (TNG) ointment has been used for almost 3 decades to treat neonatal peripheral tissue ischemia, but this product is now no longer being produced by its Canadian manufacturer. Our aim was to investigate the efficacy and safety of TNG products in newborns in neonatal intensive care units. METHODS: In this systematic review we searched Embase, CINAHL, MEDLINE, PubMed and Web of Science from inception to April 2020 for studies on the use of TNG products (TNG ointment, TNG spray, glyceryl trinitrate [GTN] patch) for the treatment of neonatal tissue ischemia. We did not apply language or study design limitations. Animal studies and duplicate records were excluded. Two reviewers screened and extracted data. The Tool for Evaluating the Methodological Quality of Case Reports and Case Series was used to assess the risk of bias of individual studies. RESULTS: We included 23 articles (20 case reports, 2 case series and 1 retrospective audit) describing the use of TNG ointment, TNG spray or GTN patch in the treatment of 39 tissue ischemia events in 37 newborns. Twenty-three (62.2%), 12 (32.4%), 1 (2.7%) and 1 (2.7%) infants received TNG ointment, GTN patch, both TNG ointment and GTN patch, and TNG spray, respectively. Nineteen (76.0%) and 7 (53.8%) injuries treated with TNG ointment and GTN patch showed complete recovery, respectively. Two (16.7%) infants treated with GTN patch experienced adverse events (i.e., methemoglobinemia) requiring treatment discontinuation. INTERPRETATION: TNG ointment presents a safe therapeutic modality for salvage therapy of neonatal tissue ischemia. Engagement of stakeholders is essential to address its recent commercial inaccessibility in Canada.