#2 Neurological system Flashcards
Benzodiazepines
Help inhibit neurotransmission
• They allosterically bind to GABAA receptors (ligand ion gated channels aka ionotropic receptors). GABA receptors are inhibitory receptors which when GABA binds to GABA A receptors associated with cl- ions to enter the post synaptic neuron making the inside more negative inhibitory postsynaptic potential (IPSP)
• Temazepam(T)(OS), Diazepam(T)(OS)(RT)(INJ), Nitrazepam(T)(OS)
• Indications can include = Insomnia (hypnotic), anxiolytic(inhibits anxiety)
Z-drugs
- Facilitate and enhance binding of GABA to GABAA receptors which are associated with cl- ions, which allows the cl- ions in the cleft to enter the post synaptic neuron to make the inside more negative = IPSP
- Zopiclone (T)
- Indications can include = Insomnia (hypnotic),
First generation antipsychotic drugs =
= Decreases dopamine levels which results in a reduction of schizophrenia and other psychoses symptoms.
• Dopamine D2 receptor antagonist by binding to dopamine receptors (as well as other monoamine receptors) and prevents dopamine binding. D2 D3 & D4 receptor subtypes are linked to the inhibition of adenyl cyclase while D1 and D5 are linked to its activation.
• Carbamazepine hydrochloride (T) (OS) (INJ) (Sup), Prochlorperazine (T)(DII), Haloperidol(T)(C)(S)(DII) , Risperidone (T)(L)(ODT)
• Indications can include = Schizophrenia and other psychoses. mania, anxiety, antiemetic in palliative care
Second generation antipsychotic drugs
= Decreases dopamine levels which results in a reduction of schizophrenia and other psychoses symptoms.
• More selectivity for D2 receptors. Many also block to 5-HT2A (aka serotonin) receptors 1st don’t do this
• Clozapine (T)(ODT)(INJ), Olanzapine (T)(OS)(BSP), Quetiapine (T)
• Indications can include = Schizophrenia, mania, depression, preventing reoccurrence in in bipolar disorder
Tricyclic and related antidepressants
Inhibit neuronal reuptake of serotonin (5-HT) and noradrenaline (the monoamines). Muscarinic, histamine, -adrenergic and dopamine (D2) receptor inhibitor
• The more NA and 5-HT remain in synapses = improve mood. D2 is inhibited as it blocks acetylcholine
• Amitriptyline hydrochloride (T)(ODT), Imipramine HCl (T)(OS), Quetiapine
• Indications can include = Depressive illness (but not recommended), neuropathic pain (unlicensed), migraine prophylaxis (unlicensed) for AH, and the same ones but licensed for IM HCL
• Replaces MAOI as they bind irreversibly to the enzyme. Although phenelzine can still be used
Monoamine-oxidase inhibitors
Monoamine-oxidase inhibitors
• Monoamine oxidase is an enzyme responsible for serotonin, dopamine and norepinephrine inactivation.
• MAOI prevent inactivation of monoamines within a neuron, causing excess neurotransmitter to diffuse into the synaptic space. So there is more serotonin = increase mood
• Phenelzine (T), Moclobemide (T)
• Indications can include = Depressive illness, social anxiety disorder
Selective Serotonin re-uptake inhibitors
Inhibit neuronal reuptake of serotonin (5-HT)
• SSRIs work by inhibiting 5-HT reuptake, so increasing synaptic concentrations.
• It works by initially activating autoreceptors to inhibit neuronal release of 5-HT, but with chronic treatment autoreceptors desensitize, so enhancing 5-HT release.
• Have antimuscarinic effects, so safer in overdose than TCAs (An anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central and the peripheral nervous system. Anticholinergics inhibit parasympathetic nerve impulses by selectively blocking the binding of the neurotransmitter acetylcholine to its receptor in nerve cells.)
• They also do not cause the cheese reaction like MAOIs = hypertension revisit cheese
• Fluoxetine (T)(L), Citalopram (T) (ODT)
• Indications can include = Depressive illness, social anxiety disorder
Other antidepressant drugs:
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Mirtazapine:
Antagonist of inhibitory pre-synaptic 2-adrenoreceptors = increases availability of monoamines for neurotransmission
• Presynaptic a2 receptors inhibit the release of noradrenaline and thus serve as an important receptor in the negative feedback control of noradrenaline release.
• It increases central noradrenergic and serotonergic neurotransmission. It has few antimuscarinic effects. Causes sedation during initial treatment.
• Indications can include = Major depression(T)(ODT)(OS)
Venlafaxine:
Serotonin and noradrenaline reuptake inhibitor – increases availability of monoamines for neurotransmission
• Serotonin and noradrenaline re-uptake inhibitor. Lacks the sedative and antimuscarinic effects of the tricyclic antidepressants.
• Indications can include = Major depression, generalised anxiety disorder (T)(C)
Lithium:
Not fully understood
• Brand specific prescribing due to differences in Bioavailability. (T)(OS)(L)
• Indications can include = Treatment and prophylaxis of mania, bipolar disorder and recurrent depression, aggressive or self-harming behaviour. Is an antipsychotic drug.
Opioid analgesic and related
Opioid µ receptor agonist
• Mu, Delta δ and Kappa opioid receptors are G-protein coupled receptors which inhibit adenyl cyclase reduce cAMP = affects cell function and have inhibitory actions on the synaptic function of neurons by acting on ion channels. Mu μ And Delta δ cause K+ channels to open and diffuse out of the cell which hyperpolarizes nerves reducing neuronal excitability when an opioid binds to the opioid receptors.
• Kappa opioid receptors when activated inhibit the opening of Ca2+ channels which usually fuse with presynaptic membrane and allow the release of neurotransmitter into the synapse * extra info*
• Codeine(T)(SYR)(INJ) Tramadol(ODT)(ODT)(C)(INJ) Morphine (OS)(T)(MDT)(SUP)(INJ) Oxycodone (C)(OS)(COS)(INJ)(MRT)(L)Fentanyl(T)(SUB/BUC/LOZ)(FILM)(NS)(PATCH) Diamorphine (Heroin) (T)(INJ)
• Indications can include = Moderate to severe pain diarrhoea and cough suppression
Local anaesthesia
= Anaesthetic • Reversibly blocking conduction of action potentials. Block Na+ Voltage Operated Channels. = Nociceptive (pain) receptors cannot carry pain signals = analgesia occurs. Smaller & rapid neurones more likely to block • Have a lipid soluble hydrophobic aromatic group, and a charged hydrophilic amide group. The bond between these groups determine the class of drug amide/ester. Ester linkage more easily broken and so less stable in solution and so cannot be stored for as long. Amide are heat stable so can be heat sterilised, esters cant. • Lidocaine (lignocaine) (INJ) • Indications = Anaesthesia
Control of the epilepsies =
An epileptic seizure is the clinical manifestation of an abnormal and excessive discharge of a set of neurons in the brain. Partial and generalized seziure
Carbamazepine
Stabilises voltage-gated sodium channels (CT) (L) (SUP) (MRT) Brand specific – Bioavailability
• Powerful inducer of microsomal enzymes, accelerates the metabolism of many other drugs e.g. oral contraceptives, warfarin and corticosteroids
• Fewer unwanted effects than phenytoin
• Sedation, mental disturbances and water retention Broader therapeutic activity – useful against absence seizures
• Indications = Focal and secondary generalised tonic0clonic seizure, primary generalised tonic-clonic seizures
