150 likes | 278 Vues
Medicines and drugs. Analgesics. What is an analgesic? How do you feel pain? . Analgesics – reduce pain. Mild analgesics.
E N D
Medicines and drugs Analgesics
What is an analgesic? • How do you feel pain?
Mild analgesics Mild analgesics, such as aspirin and paracetamol, function by stopping the transmission of pain from source to brain as they intercept the pain stimulus at the source. They do this by interfering with the production of substances, such as prostaglandins, that are produced by injured tissues and that cause pain, swelling or fever.
Strong analgesics - opioids • Strong analgesics such as morphine and diamorphine (heroin) work by temporarily bonding to receptor sites to pain impulses in the brain or other parts of the central nervous system such as the spinal cord. • This prevents the transmission of pain impulses i.e. blocking the signal without depressing the central nervous system.
Structures of analgesics aspirin paracetamol phenyl/aromatic benzene hydroxyl amide carbonyl • phenyl/aromatic benzene • ester • carboxylic acid
Structure of analgesics ibuprofen • phenyl/aromatic benzene • carboxylic acid
Aspirin – a derivative salicylic acid…. into aspirin A derivative = a new compound from changing another compound To convert salicylic acid into aspirin the hydrogen atom of the OH group is replaced by a COCH3 group to form an ester functional group which made the compound less irritating to the stomach and easier to take.
morphine morphine
heroin- another derivative • Diamorphine or heroin is a derivative of morphine or a semi-synthetic opiate. An opiate is a chemical which has the same physiological effect as morphine. • Heroin’s structure is only slightly different from morphine. Both the hydroxyl or alcohol groups in morphine have been replaced with ester groups. This is achieved by reacting the morphine with ethanoic acid; as a result an esterification occurs during which also water is produced. • Also codeine is a morphine derivative.
Using morphine - advantages • strong analgesics and therefore can relieve extreme pain • wide therapeutic window • relieves anxiety • induces relaxation • can be administered intravenously which results in faster distribution of drug
Morphine - disadvantages • euphoria, lack of self-control even dangerous behaviour • kidney failure. • addiction or physical dependence which leads to withdrawal symptoms when drug is not taken e.g. restlessness, sweating, fever, cramping, … • tolerance can become an issue with this type of drug as more of the drug needs to be taken to achieve the same effect; in order to achieve the desired effect heroin users may take doses which exceed the lethal dose • Social: • heroin users are more likely to commit crimes to pay for gradually increasing doses of the drug • loss of job • diversion of energy and money • when administered intravenously can lead to transmission of dangerous infections e.g. AIDS.