PHARMACOLOGY Flashcards
What drug class is codeine?
an opiate receptor agonsit
what are codeines 2 mechanisms of action?
Opioids decrease intracellular cAMP by inhibiting adenylate cyclase. Subsequently, the release of the nociceptive neurotransmitters substance P, GABA, dopamine, acetylcholine and noradrenaline and the hormones vasopressin, somatostatin, insulin and glucagon is inhibited.
Opioids also close N-type voltage-operated calcium channels and open calcium-dependent inwardly rectifying potassium channels. This results in hyperpolarization and reduced neuronal excitability.
what are indications of codeine?
diarrhoea, mild to moderate pain, dry or painful cough
what are the side effects of codeine?
Arrhythmias; confusion; constipation; dizziness; drowsiness; dry mouth; euphoric mood; flushing; hallucination; headache; hyperhidrosis; hypotension (with high doses); miosis; nausea (more common on initiation); palpitations; respiratory depression (with high doses); skin reactions; urinary retention; vertigo; visual impairment; vomiting (more common on initiation); withdrawal syndrome
what drug class is pethidine?
a synthetic kappa-opiate recptoragonist
what are the indications for pethidine/meperidine?
acute pain, obstetric analgesia, premedication and postoperative pain
how does pethidine compare with morphine?
its onset of action is more rapid but it has a shorter duration of action
it also has a greater affinity for the kappa-receptor than morphine
what is pethidines mechanism of action?
it binds to opiate receptors which are coupled with G-protein receptors, which activate adenylate cyclase and the production of cAMP. Opioids decrease intracellular cAMP by inhibiting adenylate cyclase. Subsequently, the release of the nociceptive neurotransmitters substance P, GABA, dopamine, acetylcholine and noradrenaline and the hormones vasopressin, somatostatin, insulin and glucagon is inhibited.
Furthermore opioids can close N-type voltage-operated calcium channels and open calcium-dependent inwardly rectifying potassium channels resulting in reduced neuronal excitability.
what are the side effects of pethidine?
Arrhythmias; confusion; constipation; dizziness; drowsiness; dry mouth; euphoric mood; flushing; hallucination; headache; hyperhidrosis; hypotension (with high doses); miosis; nausea (more common on initiation); palpitations; respiratory depression (with high doses); skin reactions; urinary retention; vertigo; visual impairment; vomiting (more common on initiation); withdrawal syndrome
what drug class is lidocaine?
an anaesthetic agent/ a sodium channel blocker
what is lidocaine’s mechanism of action?
Lidocaine alters signal conduction in neurons by blocking the signal propagation fast voltage gated sodium channels in the neuronal cell membrane. postsynaptic neuron will not depolarize and will fail to transmit an action potential. This prevents the initiation of the pain signal, and the prevention of the propagation of that signal to the brain.
In addition Lidocaine is a class Ib drug that blocks voltage-sensitive sodium channels during phase 0 of the cardiac action potential, thus slowing and depressing impulse conduction. In tissue that is depolarised, or firing at a high frequency, dissociation between pulses is decreased, promoting channel blockade and depression of conduction.
what are the side effects of lidocaine?
anxiety; arrhythmias; atrioventricular block; cardiac arrest; circulatory collapse; confusion; dizziness; drowsiness; euphoric mood; headache; hypotension (may lead to cardiac arrest); loss of consciousness; methaemoglobinaemia; muscle twitching; myocardial contractility decreased; nausea; neurological effects; nystagmus; pain; psychosis; respiratory disorders; seizure; sensation abnormal; temperature sensation altered; tinnitus; tremor; vision blurred; vomiting
what are the indications of lidocaine?
cardiopulmonary resuscitation, ventricular arrhythmias, infiltration anaesthesia, intravenous regional anaesthesia and nerve backer, dental practice, relief of pain in oral lesions, , pain relief, sore nipples from breast feeding
what drug class is tramadol?
a multi-target analgesic
what are the proposed mechanisms of tramadol’s action?
Tramadol is a centrally-acting analgesic. It is metabolised to O-desmethyl metabolite (M1). it is thought Tramadol works by binding of parent and M1 metabolite to μ-opioid receptors or
Weak inhibition of reuptake of norepinephrine and serotonin in the CNS
