Drugs and the nervous system Flashcards
Name drugs that act mainly on the nervous system
Anaesthetics Anxiolytics/hypnotic Neuromuscular blockers Antidepressants Antiparkinsonians Anticonvulsants
How are general anaesthetics administered?
By inhalation or intravenously
What do anaesthetics promote?
Analgesia
Unconsciousness
Amnesia
Loss of reflex
How do anaesthetics work?
Act on CNS to promote insensitivity. They are usually fat soluble so can cross blood-brain barrier.
Can act on membrane receptors and ion channels.
Side effects of anaesthetics
- Nausea and vomiting
- Decreased blood pressure & Cardiac output
- Shallow/rapid breathing
- Decreased kidney perfusion
- Loss of temp control
- Crosses the placenta
What drug can interact with anaesthetics and increase bleeding?
Aspirin and oral anticoagulants
What are the 4 stages of anaesthesia?
Stage 1- Analgesia
Stage 2- Excitement
Stage 3- Surgical anaesthesia (Skeletal muscle relaxation/loss of reflexes)
Stage 4- Medullary paralysis (loss of respiratory/vasomotor control)
Types of general anaesthetics
Barbiturates
Non-Barbiturates
Gases
Volatile liquids
What do you know about Nitrous Oxide (N2O)
- Used in maintaining anaesthesia with oxygen
- Used in combination with other drugs
- Potent analgesic (not potent enough to induce general anaesthesia on its own)
- Has pain relieving properties
Name some inhaled anaesthetics other than Nitrous oxide
Isoflurane
Desflurane
Sevoflurane
Side effects of some inhaled anaesthetics
Cardiovascular depression
Hypotension
Arrhythmia
Decrease CSF pressure
What do you know about Propofol?
Intravenous Anaesthetic Used for day surgery Non-Barbiturate Rapid action & recovery Can cause convulsions/ anaphylaxis
What do you know about Thiopental/Thiopentone?
Intravenous Anaesthetic
Used for brief procedures
Rapid awakening/ long lasting sedation
What do you know about Etomidate?
Anaesthetic alternative to thiopental.
Less hypotension
Negative: muscle movements, suppression of adrenocortical function.
What do you know about Ketamine?
Anaesthetic rarely used. Used mostly in children
Can be used in shocked patients
Negatives: Increases HR & BP, causes bad dreams and hallucinations during recovery.
Who are at most risk from bronchospasm and aspiration of fluid after anaesthesia?
Children
What do you know about Benzodiazepines?
Anxiolytic/ hypnotic
Cause amnesia
Negatives: No analgesic affect, Hypotension and Constipation.
What do you know about Midazolam?
Benzodiazepine/ Anxiolytic Pre-med (20 min before surgery) Can be used in children Causes sedation and induction of anaesthesia Can cause nausea and vomiting.
What do you know about Diazepam?
Benzodiazepine/Anxiolytic Used to treat anxiety Not used in children High doses can induce sleep Used prior to dental treatment
What are the disadvantages of Hypnotics?
- Can lead to dependence
- Can cause respiratory depression
- Benzodiazepines interact with alcohol
- Can cross the placenta
What do you know about Neuromuscular blocking drugs?
-Block transmission in motor nerves
-Muscle relaxants
-Reduce need for very deep anaesthetics
-Relax vocal cords
Negatives:
-Prolonged muscle paralysis/pain
-Histamine release
What do you know about Narcotic (opioid) analgesics?
Act on CNS to relieve pain Euphoric Negatives: -Nausea & vomiting -Constipation -Reduced breathing rate -Risk of addiction
Fentanyl, alfentanil, remifentanil and morphine are examples of…
Narcotic (opioid) analgesics
Local anaesthetics are used for…
Analgesia and paralysis
