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Intravenous Anesthetics and Opoids (pharmacology and Indications)

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This section can be thought of as being an anesthetic bar with different cocktails. The IV Anesthetics, The Opoids and the Specials for the VIPs.

  1. The IV Anesthetics
    1. Propofol
      1. Widely used for induction of anesthesia because of its fast on and fast off property.
      2. The dose is 1.5 to 2 mg/kg in adults or 2 to 2.5 mg/kg of body weight in children because of their faster metabolism.
      3. Pro: fast on and fast off
      4. Con: Causes drop in BP.
      5. Propofol is also known as 'Milk of Amnesia' because of its white color. We can use this to think that children drink a lot more milk than adults to remember the dose. Also, Propofol sounds like Propo-fall. It causes a fall in BP.
    2. Etiomidate
      1. Read it like Etiomi-date; a pretty date for a fragile heart who reduces all our stress!
      2. Pro: Keeps BP stable.
      3. Con: Reduces the stress meaning cortisol supression meaning adreal gland supression. Be careful what you wish for!
    3. Thiopental and Methohexital
      1. These are barbiturites and the legal age to start to abuse barbiturites is 35! Just kidding but the dose used for these drugs is 3 - 5 mg/kg. Just a memory aid. The one disadvantage is that they can cause respiratory depression.
  2. Opoids: These are easy; all of them are fentanyls
    1. Fentanyl: nearly 100x more potent than morphine
    2. Alfentanyl: read as a-fentanyl (so reduced fentanyl; almost like apnea etc). So this is less potent than fentanyl itself.
    3. Remifentanyl: the ghost. I dont know why but this reminds me of Remi the Magician. He doesn't even exist; but okay. So Remifentanyl can be broken down by blood esterases so is cleared very fast.
    4. Sufentanyl: the most potent. only 0.1 - 0.5 ug/kg of body weight is enough.
    5. Notice that all of these are getting more potent as we come down and they are in alphabetical order after fentanyl (A, R and S).
  3. The Specials for the VIPs
    1. Ketamine
      1. Read it as Keta-moundain. It pushes the heart rete and bp up, just like going up the mountain. And it acts on NMDA receptors which you can remember by the word moundain.
      2. But why is it special? Because it causes dissociative anesthesia. The patient looks awake but isn't.
    2. Midazolam
      1. It is a benzodiazepine. Its special because it causes sedation and amnesia. Now the words midazolam and benzodiazepines, I don't know why, evoke the idea of maze in my mind. So, their antidote is flumazenil; we flew over the maze hurdles.

One point to mention here is the redistribution concept. The body does not eliminate all of the anesthetic but because a lot of it is redistributed into the fats and muscle and leaves the brain, the patient awakens.