B5 Flashcards
Alendronic acid (alendronate)
Nitrogen-containing, second generation bisphosphonate
MoA: Inhibit farnesyl pyrophosphate (FPP) synthase. Inhibition of this enzyme in osteoclasts prevents the post-translational farnesylation and geranylgeranylation of small GTPase signalling proteins, such as Rac and Rho. This causes a reduction in osteoclast activity reducing bone resorption and turnover. Furthermore osteoclast survival is also affected, further increasing the ability of the bone to be rebuilt.
Use: Strengthens bone. Used to treat corticosteroid-induced osteoporosis + Paget’s disease, and to prevent osteoporosis in postmenopausal women.
Calciferol
Bioactive vitamin D is a steroid hormone required for regulating body levels of Ca2+ and phosphorus, and in mineralization of bone.
MoA: Vitamin D3 is activated by 25-hydroxylation catalysed by the 25-hydroxylase in the liver.
The active form of vitamin D3 (calcitriol) binds to the vitamin D receptor, forms a complex with another intracellular receptor, the retinoid-X receptor, that then function as transcription factors to generally activate gene expression.
Calcitriol increases the serum Ca2+ concentrations.
Raloxifene
Selective oestrogen receptor modulator
MoA: Produces oestrogen-like effects on bone + lipid metabolism. Whilst antagonising effects of oestrogen on breast + uterine tissue.
Use: Inhibits proliferation of preosteoclastic cells
Codeine
Synthetic opiate agonist
MoA: Opiate receptor agonist in the CNS
Clinical difference between morphine and pethidine?
Pethidine has a more rapid onset of action that morphine but has a shorter duration of action
Lidocaine
Anaesthetic agent (sodium channel blocker)
MoA: Lidocaine alters signal conduction in neurons by blocking the signal propagation fast voltage gated sodium channels in the neuronal cell membrane. With sufficient blockage the membrane of the postsynaptic neuron will not depolarize and will thus fail to transmit an action potential. This creates the anaesthetic effect by both preventing the initiation of the pain signal, and the prevention of the propagation of that signal to the brain.
Use: Lidocaine is used to treat ventricular tachyarrhythmias associated with Myocardial infarction. Lidocaine depresses ventricular excitability and increases the stimulation threshold of the ventricle during diastole. The sinoatrial node is, however, unaffected.
Tramadol
Multi-target analgesic
MoA not clear
Arnica montana
Homeopathic therapy used for bruising + trauma (possibly works due to manganese levels)
Dobutamine
Beta- 1-adrenergic agonist
Direct-acting inotropic agent
MoA: Via stimulation of 1-adrenergic receptors, with little effect on beta-2 or alpha-adrenergic receptors. This leads to increase myocardial contractility and stroke volume, resulting in increased cardiac output.
Isoprenaline
Beta-adrenergic agonist.
Isoproterenol is a relatively selective 2-adrenergic bronchodilator.
MoA: stimulation intracellular adenyl cyclase, elevatation of cAMP levels, therefore the relaxation of bronchial smooth muscle + inhibition of release of mediators of immediate hypersensitivity from cells, especially from mast cells
Use: Treatment of bronchospasm associated with COPD
Salbutamol
Beta-2-adrenergic agonist
MoA: stimulates beta-2-adrenergic receptors –> adenyl cyclase activation –> increases in cAMP concentration –> activation of cAMP-dependent protein kinase A. PKA modulates myosin phosphorylation + lowers intracellular calcium concentrations causing smooth muscle relaxation and bronchodilation
Use: In addition to bronchodilation, salbutamol inhibits the release of bronchoconstriction agents from mast cells, inhibits microvascular leakage, and enhances mucociliary clearance.
Norepinephrine
Alpha-adrenergic agonist
MoA: Norepinephrine functions as a peripheral vasoconstrictor by acting on both alpha-1 + alpha-2-adrenergic receptors.
It is also an inotropic stimulator of the heart and dilator of coronary arteries as a result of it’s activity at the beta-adrenergic receptors.
Phenoxybenamine
Alpha-adrenergic antagonist
MoA: Phenoxybenzamine blocks the alpha-adrenergic receptors which leads to muscle relaxation + blood vessel dilatation. This widening of the blood vessels results in a lowering of blood pressure
Use: Hypertension treatment + sweating associated with pheochromocytoma
Doxazosin
selective inhibitor of the alpha-1-adrenoceptors
Use: Hypertension treatment
Note: Prazosin has replaced doxazosin.
Muscarine
Muscarinic cholinergic receptor agonist
MoA: Muscarine binds the muscarinic acetylcholine receptors and so mimics the effects of acetylcholine.
Pilocarpine
Muscarinic cholinergic receptor agonist.
MoA: Stimulation of muscarinic receptors leading to contraction of the iris sphincter muscle and ciliary muscle.
Atracurium
Atracurium is a non-depolarising skeletal muscle relaxant
Competitive cholinergic receptor antagonist
MoA: Antagonises the neurotransmitter action of ACh by binding competitively w/ cholinergic receptor sites on the motor end-plate í muscle relaxation
What can reverse action of atracurium?
Acetylcholinesterase inhibitors such as neostigmine, edrophonium, pyridostigmine
Pilocarpine
Glaucoma treatment
Pilocarpine is a slowly hydrolysed muscarinic agonist
Botulinum A toxin
Acetylcholine release inhibitor
MoA: By binding pre-synapticly to high-affinity recognition sites on the cholinergic nerve terminals.
Causes a decrease in the release of acetylcholine, causing a neuromuscular blocking effect
Recovery occurs through proximal axonal sprouting and muscle re-innervation by formation of a new neuromuscular junction
Cocaine
Noradrenaline reuptake inhibitor/sodium channel blocker.
MoA: Cocaine produces anaesthesia by inhibiting excitation of nerve endings or by blocking conduction in peripheral nerves. This is achieved by reversibly binding to and inactivating sodium channels, which are necessary for the depolarization of nerve cell membranes and subsequent propagation of impulses along the course of the nerve.
Use: Local anaesthetic indicated for the introduction of local (topical) anaesthesia of accessible mucous membranes of the oral, laryngeal + nasal cavities.
Note: Cocaine is the only local anaesthetic with vasoconstrictive properties.
This is a result of its blockade of norepinephrine reuptake in the autonomic nervous system. Cocaine binds differentially to the dopamine, serotonin, and norepinephrine transport proteins and directly prevents the re-uptake of dopamine, serotonin, and norepinephrine into pre-synaptic neurons.
Dexamphetamine
Noradrenaline releaser
It is an amphetamine
MoA: Peripheral actions include elevations of systolic + diastolic blood pressures and weak bronchodilator and respiratory stimulant action
Dopamine
Dopamine is a precursor to norepinephrine in noradrenergic nerves and is also a neurotransmitter in the central nervous system.
MoA: In the brain, dopamine act as an agonist to the 5 dopamine receptor subtypes (D1, D2, D3, D4, D5) on beta-adrenoceptors and indirectly by causing release of norepinephrine from storage sites in sympathetic nerve endings producing positive chronotropic and inotropic effects on the myocardium, resulting in increased heart rate and cardiac contractility
Fuoxetine
Selective serotonin re-uptake inhibitor
Use: Treat depression, bulimia nervosa, premenstrual dysphoric disorder, panic disorder and post-traumatic stress
MoA: Inhibition of the re-uptake or serotonin at the serotonin re-uptake pump of the neuronal membrane, enhancing the actions of serotonin on 5HT1A autoreceptors.
SSRIs bind with significantly less affinity to histamine, acetylcholine, and norepinephrine receptors than tricyclic antidepressant drugs.
Imipramine
Catecholamine uptake inhibitor
MoA: Inhibition of the sodium-dependent serotonin transporter + sodium-dependent norepinephrine transporter preventing or reducing the reuptake of norepinephrine and serotonin by nerve cells. This leads to enhanced serotonergic transmission
Use: Imipramine is a tricyclic antidepressant
Levodopa
Dopamine replacement therapy
MoA: Levodopa is a natural form of dihydroxyphenylalanine (immediate dopamine precursor)
Use: Replace dopamine lost in parkinson’s disease
Nicotine
Nicotinic acetylcholine agonist
It is a highly addictive stimulant
MoA: Is an agonist at nicotinic acetylcholine receptors on autonomic ganglia, the adrenal medulla, neuromuscular junctions and in the brain. Dopamine binding to its receptors is responsible the euphoric and addictive properties of nicotine.
Use: Nicotine inhalers and patches are used to treat smoking withdrawal syndrome.
Phenelzine
Monoamine oxidase inhibitor
Use: Antidepressant
Pralidoxime
Cholinesterase reactivator
Use: Pralidoxime is an antidote to organophosphate pesticides and chemicals.
Sarin
Irreversible cholinesterase inhibitor
It is a nerve agent
Extremely toxic + rapid effect
Tropicamide
Muscarinic cholinergic receptor antagonist
MoA: Inhibition of the muscarinic receptor M4 –> this inhibition leads to pupil dilation and relaxation of the lens.
Use: Tropicamide is used to treat mydriasis and cycloplegia.
