Neurotransmitters within the body include excitatory and inhibitory, noradrenalin, dopamine, serotonin; acetylcholine and glutamate are examples of excitatory neurotransmitters. GABA and glycine are examples of inhibitory neurotransmitters.
General anaesthetics act mainly on the central nervous system to stop information processing; these may be given by inhalation or intravenously.
Nitrous oxide or laughing gas is used in maintain anaesthesia with oxygen and is often used in combination with other drugs. It is a potent analgesic or pain reliever. Other inhaled anaesthetics include isoflurane, desflurane and sevoflurane.
Commonly used intravenous anaesthetics include propofol, a rapid action and rapid recovery without a patient hangover. Thiopental is used in very brief procedures and has a sedative like affect. Ketamine is often used for patients in shock, it increases heart rate and blood pressure, it can lead to bad dreams and hallucinations during recovery and is also a known abused drug,
Anaesthetics work on the central nervous system to promote insensitivity to the feeling of pain. They are usually fat soluble and can cross the blood brain barrier. They can also work on the cell membrane receptors to reduce the excitability of neurones.
Typical side effects include nausea, vomiting, shallow breathing, reduced blood pressure and cardiac output, loss of temperature control, decrease kidney profusion and can cross the placenta during pregnancy.
Anxiolytics and hypnotics (Benzodiazepines)
These drugs potentiate the inhibitory effects of the neurotransmitter GABA they may act in the spinal cord and the supraspinal sites to produce muscle relaxation. these drugs also reduce the excitability of specific neurones. These drugs are part of the benzodiazepine group and include midazolam, diazepam (vallium) and loroazepam.
Further important points...