Pharmacology

Propofol

Propofol (Diprivan) is perhaps the most well known intravenous hypnotic used in perioperative and intensive care medicine. This “milk of amnesia” is prepared in a lecithin-based (purified egg yolk) emulsion. Similar to many other IV anesthetics, propofol potentiates GABA, one of the primary inhibitory neurotransmitters in the central nervous system, to hyperpolarize post-synaptic neurons. Its perfusion-dependent hepatic metabolism and favorable context-sensitive half-time make propofol infusions a wonderful option in a myriad of contexts.

As an intensivist, I most commonly use propofol (in combination with agents like fentanyl and dexmedetomidine) to provide sedation for patients on mechanical ventilation. I also use it for bedside procedures like dressing changes on patients who sustained large area burns.

As an anesthesiologist, propofol is the staple for nearly all of my general anesthetic inductions, the backbone of my total intravenous anesthesia (TIVA) cases, a great option for monitored anesthesia care (MAC) cases (remi-fol, keto-fol), a rescue antiemetic in the PACU, an anticonvulsant, a form of neuroprotection (ie, prior to deep hypothermic circulatory arrest), a way to quickly deepen an anesthetic prior to intense stimuli (ie, Mayfield skull pins), and in my opinion, a very “predictable” medication.

Although it’s a myocardial depressant, decreases afterload, and can create myoclonic movements, perhaps propofol’s most concerning side effect is PRIS – propofol infusion syndrome. This rare presentation is characterized by muscle breakdown, metabolic acidosis, kidney failure, high triglycerides, and heart failure.

Because of its lipid emulsion, propofol actually has 1.1 kcal/cc (which can add up with high dose infusions!) Also, phenolic metabolites can manifest as green urine!

Drop me a comment below with questions! 🙂

Related Articles

2 Comments

  1. I think I have heard you mention mixing propofol and epinephrine for induction on patients who may not be able to tolerate propofols’ myocardial depressant effects.
    Can you speak more to this strategy? What patients would you consider this on ? What dosing do you use

    1. With the patient population I care for (heart failure, pulmonary hypertension, etc.), I routinely use push dose pressors/inotropes during induction to offset the vasodilatory and myocardial depressant effects of propofol. I avoid answering dosing questions because there’s so much to consider (concurrent therapies, patient size/age, exaggerated response to vasoactive substances, other comorbidities, etc.), but tend to use anywhere from 5 to 20 mcg of norepinephrine and/or epinephrine, sometimes some calcium chloride, sometimes a unit or two of vasopressin. As the saying goes, you can always give more, but you can’t take it back.

Leave a Reply

Your email address will not be published. Required fields are marked *

Check Also
Close
Back to top button