Popular drugs & their actions Flashcards
Lidocaine
- local anesthetic
- anti-arrhythmia agent
- voltage-gated sodium channel blocker
Nicotine
- Ganglionic stimulant
(Agents that mimic neural transmission by stimulation of the nicotinic receptors on postganglionic autonomic neurons. Drugs that indirectly augment ganglionic transmission by increasing the release or slowing the breakdown of acetylcholine or by non-nicotinic effects on postganglionic neurons are not included here nor are the nonspecific cholinergic agonists.)
- Nicotinic agonist
Drugs that bind to and activate nicotinic cholinergic receptors (RECEPTORS, NICOTINIC). Nicotinic agonists act at postganglionic nicotinic receptors, at neuroeffector junctions in the peripheral nervous system, and at nicotinic receptors in the central nervous system. Agents that function as neuromuscular depolarizing blocking agents are included here because they activate nicotinic receptors, although they are used clinically to block nicotinic transmission.
Morphine
- Opioid
(Compounds with activity like OPIATE ALKALOIDS, acting at OPIOID RECEPTORS. Properties include induction of ANALGESIA or NARCOSIS.)
- Narcotic
(Agents that induce NARCOSIS. This term is considered outdated due to imprecision but continues to be widely used. Originally, agents that caused somnolence or induced sleep (STUPOR); now, any derivative, natural or synthetic, of OPIUM or MORPHINE or any substance that has their effects. Narcotics are potent inducers of ANALGESIA and OPIOID-RELATED DISORDERS.)
Botulinum toxin
Botulinum toxin is a protein and neurotoxin produced by the bacterium Clostridium botulinum.[1][2] It is the most acutely toxic substance known, with an estimated human median lethal dose (LD-50) of 1.3–2.1 ng/kg intravenously or intramuscularly and 10–13 ng/kg when inhaled.[3] Botulinum toxin (BTX) can cause botulism, a serious and life-threatening illness in humans and animals. Three forms of botulinum toxin type A (Botox, Dysport and Xeomin) and one form of botulinum toxin type B (MyoBloc) are available commercially for various cosmetic and medical procedures.
Mechanism:
The heavy chain of the toxin is particularly important for targeting the toxin to specific types of axon terminals. The toxin must get inside the axon terminals to cause paralysis. Following the attachment of the toxin heavy chain to proteins on the surface of axon terminals, the toxin can be taken into neurons by endocytosis. The light chain is able to cleave endocytotic vesicles and reach the cytoplasm. The light chain of the toxin has protease activity. The type A toxin proteolytically degrades the SNAP-25 protein, a type of SNARE protein. The SNAP-25 protein is required for vesicle fusion that releases neurotransmitters from the axon endings (in particular acetylcholine).[66] Botulinum toxin specifically cleaves these SNAREs, so prevents neurosecretory vesicles from docking/fusing with the nerve synapse plasma membrane and releasing their neurotransmitters.
Risperidone
- Antipsychotic
- Dopamine Antagonist
- Serotonin Antagonist
Risperidone is used to treat the manifestations of psychotic disorders. It appears to produce a significant improvement in both the positive and negative symptoms of schizophrenia. /Included in US product label/
Fluoxetine
(Prozac)
- Serotonin Uptake inhibitor (inhibits its target: Sodium-dependent serotonin transporter)
- at least 60-80% of an oral dose appears to be absorbed
Compounds that specifically inhibit the reuptake of serotonin in the brain. This increases the serotonin concentration in the synaptic cleft which then activates serotonin receptors to a greater extent. These agents have been used in treatment of depression, panic disorder, obsessive-compulsive behavior, and alcoholism, as analgesics, and to treat obesity and bulimia. Many of the ADRENERGIC UPTAKE INHIBITORS also inhibit serotonin uptake; they are not included here.
Clozapine
- GABA antagonist
- Serotonin antagonist
- Dopamine antagonist
- antipsychotic
Ziconotide (Conotoxin)
- Analgesic (non-narcotic)
- Ca channnel blocker
Ziconotide is used intrathecally for the management of severe chronic pain in patients who are intolerant of or do not obtain adequate pain relief from other therapies (e.g., systemic analgesics, adjunctive therapies, intrathecal morphine therapy) when intrathecal therapy is warranted.
Ziconotide acts as a selective N-type voltage-gated calcium channel blocker.[4][5] This action inhibits the release of pro-nociceptive neurochemicals like glutamate, calcitonin gene-related peptide (CGRP), and substance P in the brain and spinal cord, resulting in pain relief.
Diazepam (e.g. Valium)
- adjuvant anasthetic
- anti-anxiety agent
- GABA modulator
Substances that do not act as agonists or antagonists but do affect the GAMMA-AMINOBUTYRIC ACID receptor-ionophore complex. GABA-A receptors (RECEPTORS, GABA-A) appear to have at least three allosteric sites at which modulators act: a site at which BENZODIAZEPINES act by increasing the opening frequency of GAMMA-AMINOBUTYRIC ACID-activated chloride channels; a site at which BARBITURATES act to prolong the duration of channel opening; and a site at which some steroids may act. GENERAL ANESTHETICS probably act at least partly by potentiating GABAergic responses, but they are not included here.
- muscle relaxant
Phenobarbital
- GABA modulator
- Excitatory amino acid antagonist
- Hypnotic/Sedative
- Anticonvulsant
A barbituric acid derivative that acts as a nonselective central nervous system depressant. It promotes binding to inhibitory GAMMA-AMINOBUTYRIC ACID subtype receptors, and modulates chloride currents through receptor channels. It also inhibits glutamate induced depolarizations.
Bicuculline
- Convulsant
- GABA A receptor antagonist
An isoquinoline alkaloid obtained from Dicentra cucullaria and other plants. It is a competitive antagonist for GABA-A receptors.
Year introduced: 1980(1975)
Ketamine
- NMDA antagonist (channel blocker)
- Analgesic
- Dissociative
A cyclohexanone derivative used for induction of anesthesia. Its mechanism of action is not well understood, but ketamine can block NMDA receptors and may interact with sigma receptors.
Year introduced: 1973
Note: presumed action - decreased Ca influx, changes in kinases, changes in transcription factors leading to increase in BDNF secretion
Mecamylamine
- Nicotinic ACh antagonist (channel blocker)
A nicotinic antagonist that is well absorbed from the gastrointestinal tract and crosses the blood-brain barrier. Mecamylamine has been used as a ganglionic blocker in treating hypertension, but, like most ganglionic blockers, is more often used now as a research tool.
Ganglionic Blockers - Agents having as their major action the interruption of neural transmission at nicotinic receptors on postganglionic autonomic neurons. Because their actions are so broad, including blocking of sympathetic and parasympathetic systems, their therapeutic use has been largely supplanted by more specific drugs. They may still be used in the control of blood pressure in patients with acute dissecting aortic aneurysm and for the induction of hypotension in surgery.
Memantine
- Probably blocks extrasynaptic (not at the synapse, but at the soma) NMDA receptors
- probably prevents excitotoxicity
- only approved non-acetylChesterase inhibitor treatment for Alzheimer’s
MK 801 (Dizocilpine Maleate)
- non-competitive NMDA antagonist
A potent noncompetitive antagonist of the NMDA receptor (RECEPTORS, N-METHYL-D-ASPARTATE) used mainly as a research tool. The drug has been considered for the wide variety of neurodegenerative conditions or disorders in which NMDA receptors may play an important role. Its use has been primarily limited to animal and tissue experiments because of its psychotropic effects.
Year introduced: 1991
PCP (Phencyclidine)
- NMDA antagonist
A hallucinogen formerly used as a veterinary anesthetic, and briefly as a general anesthetic for humans. Phencyclidine is similar to KETAMINE in structure and in many of its effects. Like ketamine, it can produce a dissociative state. It exerts its pharmacological action through inhibition of NMDA receptors (RECEPTORS, N-METHYL-D-ASPARTATE). As a drug of abuse, it is known as PCP and Angel Dust.
Year introduced: 1973(1964)
Caffeine
- inhibits PDE breakdown of cAMP
A methylxanthine naturally occurring in some beverages and also used as a pharmacological agent. Caffeine’s most notable pharmacological effect is as a central nervous system stimulant, increasing alertness and producing agitation. It also relaxes SMOOTH MUSCLE, stimulates CARDIAC MUSCLE, stimulates DIURESIS, and appears to be useful in the treatment of some types of headache. Several cellular actions of caffeine have been observed, but it is not entirely clear how each contributes to its pharmacological profile. Among the most important are inhibition of cyclic nucleotide PHOSPHODIESTERASES, antagonism of ADENOSINE RECEPTORS, and modulation of intracellular calcium handling.
Sildenafil (viagra) (but also tadalafil and vardenafil)
Sildenfail is a vasoactive agent used to treat erectile dysfunction and reduce symptoms in patients with pulmonary arterial hypertension (PAH). Sildenafil elevates levels of the second messenger, cGMP, by inhibiting its breakdown via phosphodiesterase type 5 (PDE5). PDE5 is found in particularly high concentrations in the corpus cavernosum, erectile tissue of the penis. It is also found in the retina and vascular endothelium. Increased cGMP results in vasodilation which facilitates generation and maintenance of an erection.
Scopolamine
- cholinergic & muscarinic antagonist
An alkaloid from SOLANACEAE, especially DATURA and SCOPOLIA. Scopolamine and its quaternary derivatives act as antimuscarinics like ATROPINE, but may have more central nervous system effects. Among the many uses are as an anesthetic premedication, in URINARY INCONTINENCE, in MOTION SICKNESS, as an antispasmodic, and as a mydriatic and cycloplegic.
MDMA
(Ecstasy, Methylenedioxymethamphetamine)
An N-substituted amphetamine analog. It is a widely abused drug classified as a hallucinogen and causes marked, long-lasting changes in brain serotonergic systems. It is commonly referred to as MDMA or ecstasy.
MDMA acts as a releasing agent of serotonin, norepinephrine, and dopamine.[105] It enters neurons via carriage by the monoamine transporters.[105] Once inside, MDMA inhibits the vesicular monoamine transporter, which results in increased concentrations of serotonin, norepinephrine, and dopamine in the cytoplasm,[106] and induces their release by reversing their respective transporters through a process known as phosphorylation.
Safrole, a colorless or slightly yellow oily liquid, extracted from the root-bark or the fruit of the sassafras tree is the primary precursor for all manufacture of MDMA.
Donepezil
Donepezil (Aricept), is a centrally acting reversible acetyl cholinesterase inhibitor. Its main therapeutic use is in the treatment of Alzheimer’s disease where it is used to increase cortical acetylcholine. Donepezil is postulated to exert its therapeutic effect by enhancing cholinergic function. This is accomplished by increasing the concentration of acetylcholine through reversible inhibition of its hydrolysis by acetylcholinesterase. If this proposed mechanism of action is correct, donepezil’s effect may lessen as the disease process advances and fewer cholinergic neurons remain functionally intact. Donepezil has been tested in other cognitive disorders including Lewy body dementia and Vascular dementia, but it is not currently approved for these indications. Donepezil has also been studied in patients with Mild Cognitive Impairment, schizophrenia, attention deficit disorder, post-coronary bypass cognitive impairment, cognitive impairment associated with multiple sclerosis, and Down syndrome.
Tetrahydrocannabinol
Cannabinoid receptor agonist
A psychoactive compound extracted from the resin of Cannabis sativa (marihuana, hashish). The isomer delta-9-tetrahydrocannabinol (THC) is considered the most active form, producing characteristic mood and perceptual changes associated with this compound. Dronabinol is a synthetic form of delta-9-THC.
Lysergic Acid Diethylamide
- Serotonic agonist
Semisynthetic derivative of ergot (Claviceps purpurea). It has complex effects on serotonergic systems including antagonism at some peripheral serotonin receptors, both agonist and antagonist actions at central nervous system serotonin receptors, and possibly effects on serotonin turnover. It is a potent hallucinogen, but the mechanisms of that effect are not well understood.
Cocaine
- Dopamine uptake inhibitor
An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake.
Psilocybin
- possibly activate inhibitory GABA neurons
- decreases in cerebral bloodflow (most active regions before psilocybin became least active after the drug)
The major of two hallucinogenic components of Teonanacatl, the sacred mushroom of Mexico, the other component being psilocin. (From Merck Index, 11th ed)
Naloxone
A specific opiate antagonist that has no agonist activity. It is a competitive antagonist at mu, delta, and kappa opioid receptors.
