Precipitation in Gallipoli: sugammadex / amiodarone & sugammadex / dobutamine & sugammadex / protamine.

ISSN © 2013 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. Dear Editor, Sugammadex is a modifi ed gamma cyclodextrin . Cyclodextrins are water soluble cyclic oligosaccharides with a lipophilic core. Sugammadex has quickly found a place in clinical use for selective antagonism of neuromuscular blockade with rocuronium . Sugammadex quickly encapsulates steroidal neuromuscular blockers, increasing the amount of encapsulated steroidal neuromuscular blockers in plasma and separating the blockers from the nicotinic acetylcholine receptors . Apart from its use with steroidal neuromuscular blockers, it is known that sugammadex interacts with over 40 lipophilic, steroidal and non-steroidal drugs. These drugs include: propofol, thiopental, fentanyl, remifentanil, vancomycin, gentamicin, salbutamol, aminophylline, atropine, digoxin, ephedrine, phentolamine, verapamil, cortisone and hydrocortisone . Previous research shows that, apart from steroidal muscle relaxants, sugammadex forms precipitates with protamine . There is no clinical data on whether sugammadex forms precipitates with other drugs, commonly used in clinical practice. The hypothesis of this study is to investigate whether the chemical and physical properties of sugammadex would contribute to a precipitation reaction with drugs commonly used in clinical practice. With this aim, simply 0.1 mL containing 100 mg.mL sugammadex was mixed on a glass slide with the same volume of a drug and the presence or absence of precipitation was determined under the microscope. The drugs investigated are all commonly used in clinical anesthesia practice. They include: adrenalin (1 mg.mL), atropine (1 mg.mL), amiodarone (50 mg.mL), aminophylline (24 mg.mL), ornidazole (500 mg.3 mL), bupivacaine (5 mg.mL), cefazolin sodium (250 mg.mL), dexmedetomine (100 μg.mL), dobutamine (12.5 mg.mL), dopamine (8 mg.mL), ephedrine (0.05 g.mL), esmolol (10 mg.mL), esomeprazole (40 mg.mL), etomidate (2 mg.mL), fentanyl (50 μg.mL), fl umazenil (0.1 mg.mL), furosemide (10 mg.mL), gentamicin (40 mg.mL), glyceryl trinitrate (5 mg.mL), heparin (1,000 IU.mL), hydrocortisone (250 mg.mL), crystallized insulin (100 IU.mL), Calcium (Calcium Gluconate Monohydrate 225 mg.10 mL + Calcium levulinate dihitrate 572 mg.10 mL), ketamine (50 mg.mL), levobupivacaine (7.5 mg.mL), magnesium sulphate (1.2 mEq.mL), metamizol sodium (0.5 g.mL), methylergobasin maleate (0.2 mg.mL), metoclopramide (5 mg.mL), metoprolol (1 mg.mL), morphine (0.01 g.mL), midazolam (5 mg.mL), n-acetylcysteine (100 mg.mL), naloxone (0.4 mg.mL), neostigmine (0.5 mg.mL), nitroprusside (12 mg.mL), noradrenaline (1 mg.mL), oxytocin (5 IU.mL), paracetamol (10 mg.mL), thiopental sodium (25 mg.mL), pethidine (50 mg.mL), pheniramine (22.75 mg.mL), phenytoin (50 mg.mL), piracetam (1 g.5 mL), prednisolone (25 mg), prilocaine (20 mg.mL), propafenone (3.5 mg.mL), pro tamine hydrochloride (1,000 IU.mL), potassium (1 mEq.mL), remifentanil (5 mg.mL), cefuroxime axetil (125 mg.mL), sulbactam-ampicillin (200 mg.mL), succinylcholine (20 mg.mL), tenoxicam (10 mg.mL), theophylline (24 mg. mL), tramadol (50 mg.mL), and vitamin K (10 mg.mL). A scale of 0-4 was used to evaluate the test, with 0 being no precipitation and 4+ being strong precipitation. Within seconds, sugammadex (100 mg.mL) scored 4+ precipitation with amidarone (50 mg.mL), dobutamine (12.5 mg. mL) and protamine hydrochloride (1,000 IU.mL). There are reports on the incompatibility and precipitation of anesthetic drugs . Thiopental, with basic pH, reacts with acidic muscle relaxants such as suxamethonium, mivacurium, vecuronium and rocuronium, causing precipitation . Similarly, thiopental causes precipitation with local anesthetics due to pH differences . Previous experimental studies have shown that thiopental reacting with various drugs may form thiopental acid crystals due to precipitation, which may cause pulmonary embolism . Sugammadex has a pH of 7.5 and the precipitation reaction with protamine may be related to the molecules’ ionic weight .