Category: Pharmacology & Therapeutics
Keywords: nitroglycerin, administration set, drug sorption, PVC tubing, polyethylene, SCAPE (PubMed Search)
Posted: 6/8/2023 by Matthew Poremba
(Updated: 12/2/2023)
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Nitroglycerin easily migrates into polyvinyl chloride (PVC), a plastic commonly used in intravenous tubing due to its flexibility and low cost. A slow rate of flow and long tubing length increase the loss of nitroglycerin. While using less absorptive tubing (i.e. polyethylene or polypropylene) when administering nitroglycerin is recommended, most published clinical studies looking at nitroglycerin have used PVC tubing.
A 1989 study compared nitroglycerin delivery through PVC tubing and low sorbing tubing at various concentrations and flow rates.1 Samples were obtained from the nitroglycerin bottle and the distal end of the tubing at several time points.
A 2018 study enrolled 8 volunteers to receive nitroglycerin infusions through PVC tubing and low sorbing polyolefin tubing.2
Bottom Line: Most studies evaluating nitroglycerin use in various clinical scenarios have used PVC tubing. Doses based on use with PVC tubing may be too high when using less absorptive tubing. Employing more conservative dosing strategies when using low sorbing tubing can help mitigate the risk of adverse effects (i.e. hypotension, headache).
Category: Pharmacology & Therapeutics
Keywords: Myasthenia gravis, Myasthenic crisis, neuromuscular blocker, paralytic, rocuronium, vecuronium, succinylcholine (PubMed Search)
Posted: 4/1/2023 by Matthew Poremba
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Myasthenia gravis is an autoimmune disease of the neuromuscular junction, most commonly due to antibodies attacking acetylcholine receptors in the postsynaptic membrane. Up to 30% of patients with myasthenia gravis will experience a myasthenic crisis during their disease course. If rapid sequence intubation is indicated, the unique characteristics of this patient population must be considered in the event use of a paralytic is necessary. All paralytic agents can be expected to last significantly longer, and an unpredictable response may be seen with depolarizing agents - therefore non-depolarizing agents are preferred in this population.
Non-Depolarizing Agents (Rocuronium, Vecuronium)
Depolarizing Agents (Succinylcholine)
Roper J, Fleming ME, Long B, Koyfman A. Myasthenia Gravis and Crisis: Evaluation and Management in the Emergency Department. J Emerg Med. 2017;53(6):843-853.
Abel, Mark, and James B Eisenkraft. “Anesthetic implications of myasthenia gravis.” The Mount Sinai journal of medicine, New York vol. 69,1-2 (2002): 31-7.
Category: Pharmacology & Therapeutics
Keywords: magnesium, migraine, headache (PubMed Search)
Posted: 1/7/2023 by Matthew Poremba
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Magnesium has been associated with function of serotonin and vascular tone regulation, both of which are mechanisms that implicate there may be a role in treatment of migraine. As this is a well-tolerated medication with a good safety profile, there is interest in utilizing this medication in the treatment of migraines. However, studies comparing magnesium to standard migraine treatments are lacking.
A recent single-center, double-blinded, randomized controlled trial compared magnesium, metoclopramide and prochlorperazine for treatment of migraine in the ED. Patients received either magnesium sulfate 2 grams, metoclopramide 10 mg or prochlorperazine 10 mg intravenously over 20 minutes. Adjunctive and rescue medications could be used at the providers discretion.
Pain was assessed with the 11-point Numeric Rating Scale at baseline and at several timepoints after completion of the infusion. Median change in pain score was found to be -3 in all groups at 30 minutes. Post-hoc analysis found magnesium to be non-inferior to prochlorperazine and metoclopramide at this time point. No difference in ED length of stay was found between groups. Adverse events were reported in 5% of patients receiving magnesium, 4.5% in patients receiving metoclopramide and 11.5% in prochlorperazine patients (p = 0.51). The most common adverse events were dizziness, akathisias, and anxiety.
Bottom Line: Magnesium can be used as an adjunctive agent in the treatment of migraines, and may also be considered as an alternative agent when other options such as prochlorperazine and metoclopramide are not appropriate. A reasonable dose would be 2 grams IV infused over 20 minutes. The team should follow-up 30-60 minutes after infusion to assess response to therapy.
Kandil M, Jaber S, Desai D, et al. MAGraine: Magnesium compared to conventional therapy for treatment of migraines. Am J Emerg Med. 2021 Jan;39:28-33. doi: 10.1016/j.ajem.2020.09.033