GENERAL ANESTHETICS

List of drugs

Inhalation anesthetics: Diethyl ether, Halothane, Nitrous oxide

Intravenous anesthetics: Thiopental sodium, Ketamine, Sodium oxybate

Mechanism of action

Inhalation anesthetics produce two activities:

a) change the physicochemical properties of neuronal membranes thus resulting in decrease of excitability of neurons;

b) potentiate GABAergic inhibition of central nervous system.

The mechanism of action of intravenous anesthetics you should not study.

Pharmacological effects

These drugs induce the inhibition of central nervous system below normal state and produce the general anaesthesia (narcosis).

Indications

General anesthesia is essential to surgical practice, because it renders patients analgesic, amnesic, and unconscious, while causing muscle relaxation and suppression of undesirable reflexes.

1. Induction to anaesthesia: using of intravenous anesthetics before applying of inhalation anesthetics (Thiopental sodium, intravenous Ketamine).

2. Basal anaesthesia: using of intravenous anesthetics along with inhalation anesthetics (Thiopental sodium, intramuscular Ketamine, Sodium oxybate)

3. Mixed anaesthesia: combined using of inhalation anesthetics (e.g. Halothane + Nitrous oxide)

All of these approaches we need to use for decreasing of side effects of narcosis, producing more deeper anaesthesia etc.

Side effects:

Diethyl ether produces the irritative action on the upper respiratory tract (up to respiratory arrest) and on the cardiac system (up to cardiac arrest)

Ketamine can induce the postoperative hallucinations.

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ANALGESIC DRUGS

List of drugs

Opioid (narcotic) analgesics: Morphine hydrochloride, Trimeperidine, Fentanyl

Non-opioid (non-narcotic) analgesics: Acetylsalicylic acid, Paracetamol (Acetaminophen), Metamizole

Mechanism of action

Opioid (narcotic) analgesics produce stimulation of m-opioid receptors (m = “mu”).

Non-opioid analgesics produce inhibition of cyclooxygenase type 1 (COX-1) and, as result, impairment of prostaglandin synthesis.

Pharmacological effects

Opioid and non-opioid analgesics decrease the pain by blocking of the transmission of pain stimuli in the central nervous system without influencing all another types of sensation (tactile sense etc.)

Indications

1. Traumatic pain (any opioid analgesics)

Opioid analgesics → stimulation of m-opioid receptors → blockage of the transmission of pain stimuli in the central nervous system→ pain relieving.

2. Ischemic pain (any opioid analgesics, but more preferable is Fentanyl due to the most strong painkilling activity)

Opioid analgesics → stimulation of m-opioid receptors → blockage of the transmission of pain stimuli in the central nervous system→ pain relieving.

3. Inflammatory pain (e.g. toothache, headache etc.) (any non-opioid analgesics)

Non-opioid analgesics → inhibition of COX-1 and, as result, impairment of prostaglandin synthesis → blockage of the transmission of pain stimuli in the central nervous system→ pain relieving.

Side effects:

Morphine hydrochloride and Fentanyl can produce inhibition of respiratory center.

Non-opioid analgesics can produce the damage of gastric mucosa (gastritis, ulcer disease).

NB! In case of overdosage of opioid analgesics we should use Naloxone hydrochloride which produces the blockage of m-opioid receptors and thus inhibits the activity of opioid analgesics.

HYPNOTIC DRUGS

List of drugs

Nitrazepam, Zopiclone

Mechanism of action

Nitrazepam and Zopiclone bind to the GABA-receptors (not in the active site of receptors, but in additional (allosteric) site of receptors) and potentiate GABAergic inhibition of central nervous system.

NB! GABA-receptors = receptors for gamma-aminobutyric acid

Pharmacological effects

These drugs induce the inhibition of central nervous system below normal state and produce the sleeping.

Indications

1. Insomnia

Nitrazepam, Zopiclone → potentiation of GABAergic inhibition of central nervous system → producing of sleeping.

Date: 2015-12-18; view: 791