Atropine is an anticholinergic (specifically an antimuscarinic) that works by inhibiting the parasympathetic nervous system. It can be administered IV, IM, SC, and even down an endotracheal tube! However, since atropine crosses the blood-brain barrier,...

Albumin is the most abundant globular plasma protein, an important transport protein, and the primary determinant of oncotic pressure (the colloid osmotic pressure that opposes hydrostatic pressure in determining transcapillary flow). The colloid versus...

Neostigmine is a polar acetylcholinesterase inhibitor (does NOT cross the blood-brain barrier) that is routinely used to reverse non-depolarizing neuromuscular blocking agents (NMBA) like rocuronium, vecuronium, and cisatracurium. These NMBAs are competitive inhibitors at...

Calcium chloride (CaCl2) is an ionic form of intravenous calcium repletion with roughly three times more bioavailable calcium than its organic counterpart - calcium gluconate. The teaching that one needs a functional liver to metabolize...

Glycopyrrolate (Robinul) is an anticholinergic (specifically an anti-muscarinic) that works on peripheral acetylcholine receptors in the heart (SA node, AV node), exocrine glands, and smooth muscle. Because of its polar, quaternary amine structure, it...

Dexamethasone (Decadron) is synthetic adrenocortical steroid roughly 25 times more potent than hydrocortisone and devoid of mineralcorticoid (“sodium retaining”) properties. Therefore, it's primarily used for long acting, anti-inflammatory effects. In the ICU, I most commonly...

Flumazenil (Romazicon) is a reversal agent for benzodiazepines ("benzos") through competitive inhibition at the GABA(A)/benzo receptor complex. Since it serves as an antidote for benzos, we have to consider the effects of acute withdrawal...

Potassium chloride (KCl) is a form of intravenous electrolyte repletion in hypokalemia - the most common electrolyte disorder in hospitalized patients often caused by diarrhea, vomiting, loop/thiazide diuretics, steroids, and poor intake among many...