Drug List Block 6 Flashcards
Amytriptiline
Amitriptyline, is a sedating antidepressant, and so can aide sleep patterns.
causes there to be a potentiation or prolonging of neuronal activity, since reuptake of norepinephrine and serotonin is important in termination of transmitting activity.
Ssri
Chloropormazine
Chlorpromazine is an antagonist on dopaminergic-receptors (subtypes D1, D2, D3 and D4), serotonergic-receptors (5-HT1 and 5-HT2), histaminergic-receptors (H1-receptors), alpha1/alpha2-receptors and muscarinic (cholinergic) M1/M2-receptors. Chlorpromazine’s antipsychotic actions are due to long-term adaptation by the brain to blocking dopamine receptors. Chlorpromazine has several other actions and therapeutic uses, including as an antiemetic and in the treatment of intractable hiccup
Clozapine
Clozapine is indicated for the treatment of schizophrenia. It is a selective monoaminergic antagonist with high affinity for 5HT2, and D2 receptors. D2 antagonism relieves positive symptoms while 5-HT2A antagonism alleviates negative symptoms. However it has been shown to bind to 1 and 2 adrenergic, muscarinic M1-5 receptors and H1 histaminergic receptors, which may explain its therapeutic and side effect profile.
Citalopram
Ssri
Citalopram is used to treat depression associated with mood disorders. The mechanism of action is via blocking the reuptake of serotonin at the serotonin reuptake pump of the neuronal membrane, with little effect on norepinephrine and dopamine reuptake. This enhances the actions of serotonin on 5HT1A autoreceptors. Citalopram does not inhibit monoamine oxidase.
SSRIs bind with significantly less affinity to histamine, acetylcholine, and norepinephrine receptors than tricyclic antidepressant drugs.
Diazepam
Benzodiazepines generates the same active metabolite as chlordiazepoxide and clorazepate and binds nonspecifically to benzodiazepine receptors (BR). These receptors mediate sleep, affects muscle relaxation, anticonvulsant activity, motor coordination, and memory. The BRs are believed to be linked to the GABA-A receptors, and activation of the BRs lead to increasing the affinity of GABA for its receptor, enhancing its effects. Binding of GABA to its receptor opens the chloride channel, causing hyperpolarisation and preventing further cell excitation.
Haloperidol
Haloperidol is a psychotropic agent, with sedative and antiemetic activity used to treat schizophrenia
1) Depressing the CNS thereby interrupting the impulse between the diencephalon and the cortex
2) Antagonizing the actions of glutamic acid within the extrapyramidal system,
3) Inhibiting catecholamine receptors
4) Inhibiting the reuptake of various neurotransmitters in the midbrain
5) Directly affect the chemoreceptor trigger zone (CTZ) through the blocking of dopamine receptors.
Lithium
Lithium is used in the treatment of bipolar disorder, as it counteracts both mania and depression. The active principle is the lithium ion Li+, which can displace K+, Na+ and even Ca2+, in several critical neuronal enzymes and neurotransmitter receptors. However, the exact mechanism of action is still unknown. Lithium’s therapeutic action may be due to a number of effects, ranging from inhibition of enzymes such as glycogen synthase kinase 3, inositol phosphatases, or modulation of glutamate receptors.
Phenelzine
Antidepressant
is believed to irreversibly inhibit monoamine oxidase (MAO). There are two forms of MAO, (A+B). MAO-A is found in cells in the periphery, whilst MAO-B is found extracellularly and predominately in the brain. The two subtypes are different substrates, with MAO-A catalysing the breakdown of serotonin, norepinephrine, epinephrine, dopamine and tyramine, whilst MAO-B acts on phenylethylamine, norepinephrine, epinephrine, dopamine and tyramine. As Phenelzine inhibits MAO, it therefore increases the concentration of free amines, most specifically serotonin and norepinephrine. MAO A inhibition is thought to be more relevant to antidepressant activity as selective MAO B inhibitors (selegiline), have no antidepressant effects.
Risperidone
Risperidone is an atypical antipsychotic therapy, used to treat delusional psychosis, bipolar disorder and psychotic depression. Its mechanism of action is inhibition of
1) Dopaminergic D2 receptors in the limbic system which alleviates symptoms of schizophrenia.
2) Serotonergic 5-HT2 receptors in the mesocortical tract. This causes an excess of dopamine and an increase in dopamine transmission and an elimination of core negative symptoms. Usefully dopamine receptors in the nigrostriatal pathway are not affected and therefore extrapyramidal effects are avoided.
3) Alpha (1), alpha (2) adrenergic receptors and histamine H1 receptors.
Venlafaxine
The exact mechanism of action of venlafaxine is unknown. However venlafaxine and its metabolite, O-desmethylvenlafaxine (ODV) potently inhibit serotonin and norepinephrine reuptake and weakly inhibit dopamine reuptake. This is associated with a potentiation of neurotransmitter activity in the CNS.
Similar to SSRIs, Venlafaxine is not active at histaminergic, muscarinic, or 1-adrenergic receptors, nor does it inhibit monoamine oxidase (MAO) activity.
Zoplicone
Zopiclone is a nonbenzodiazepine hypnotic indicated for the short-term treatment of insomnia. Zopiclone’s mechanism of action is via by binding the α1, α2, α3 and α5 GABAA containing receptors as full agonists modulating the GABABZ receptor chloride channel macromolecular complex. This enhances the inhibitory actions of GABA to produce the hypnotic and anxiolytic effects of zopiclone.
