Common drugs and their effects Flashcards
What are the different causes of pain?
Cancer pain, neuropathic pain from damage within central nervous system to sensory pathways leading to sensitisation of these pathways with the result that normally innocuous stimuli are perceived as pain, musculoskeletal pain due to injury, trauma, sport, or a disorder such as arthritis, inflammation is usually accompanied by pain due to the release of locally acting chemical mediators, pressure on tissues and excessive heat or cold.
What is the purpose of pain?
To warn the body of damage and leads to response to avoid further pain.
What is the WHO analgesic ladder?
Non-opioid drugs (aspirin, paracetamol, and non-steroidal anti inflammatories (NSAIDs) such as ibuprofen) –> Weak opioids (Codeine) –> strong opioids (morphine, pethidine, diamorphine or methadone).
What are common side effects of opioid analgesics?
These vary between the different drugs, but the most common are nausea and vomiting, particularly in the early stages of use, also constipation, dry mouth and biliary spasm (pain in the gallbladder). At larger doses muscle rigidity, hypotension (low bp) and respiratory depression.
What are the characteristics of paracetamol?
Its an atypical nonsteroidal anti-inflammatory NSAID. Can be given IV, orally or rectally. No more than 4g should be given in 24 hours. It’s rapidly absorbed, distributed to all compartments and crosses the blood brain barrier. Its main effects are to relieve mild pain and pyrexia/ fever, and is also a weak anti-inflammatory. Metabolised by the liver.
What is a toxic dose or paracetamol and what are the signs?
Between 10-15g can cause fatal toxicity of the liver and kidney, the toxic metabolites accumulate in the liver and kidney tubules and lead to necrosis (premature cell death). The early features of poisoning are nausea and vomiting which would normally settle within 24 hours. If symptoms persist beyond this time often with the right subcostal pain and tenderness which indicates liver necrosis.
What do typical NSAIDs do?
Provide relief from fever, pain, and inflammation. Most have significant unwanted effects which can be particularly troublesome in the elderly.
What are the effects of morphine?
Morphine can also produce a range of other effects, increased pain transmission or hyperalgesia (abnormally increased sensitivity to pain), euphoria, respiratory depression, suppression of cough, nausea, and vomiting amongst others. Continued use of morphine can lead to tolerance and dependence.
How is morphine administered?
Morphine can be given by mouth but its absorption is slow and erratic, it is more commonly given by intravenous injections for acute severe pain. For chronic pain oral preperations are more commonly used. It can also be given intrathecally (injection into spinal canal).
How do drugs used for hypertension work?
they can reduce peripheral resistance by vasodilation,, reduce cardiac output, reducing heart rate or contraction power, and reducing blood volume. Beta blockers and long acting calcium channel blockers reduce heart rate and contractility. Diuretics are used to reduce blood volume.
What is the aim of antimicrobials?
To find a feature of the microbe that is different from the host, in this way the feature can be exploited to target the microbe either directly destroying it or making it the target of the immune system.
What is anti-microbial resistance?
The bacteria that are being targeted by antimicrobials have evolved, and have developed mechanisms to become resistant to the antibiotics. This is called anti-microbial resistance (AMR) and it is a great threat to the future control of infectious diseases resulting from bacteria.
How can you defend against viruses?
The most effective and safest form of defence against viruses is to develop immunity, this is where the human immune system detects and recognises an antigen and then mounts a specific response to it, usually through the production of antibodies specific to the antigen and also by a cell mediated response. This immunity can be developed either by exposure to the antigen or through the use of a vaccine which presents the antigen to the human immune system in a safe way so that it can be recognised and remembered.
