Opioid Receptor Antagonist
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Opioid Receptor Antagonist
An opioid antagonist, or opioid receptor antagonist, is a receptor antagonist that acts on one or more of the opioid receptors. Naloxone and naltrexone are commonly used opioid antagonist drugs which are competitive antagonists that bind to the opioid receptors with higher affinity than agonists but do not activate the receptors. This effectively blocks the receptor, preventing the body from responding to opioids and endorphins. Some opioid antagonists are not pure antagonists but do produce some weak opioid partial agonist effects, and can produce analgesic effects when administered in high doses to opioid-naive individuals. Examples of such compounds include nalorphine and levallorphan. However, the analgesic effects from these specific drugs are limited and tend to be accompanied by dysphoria, most likely due to additional agonist action at the κ-opioid receptor. As they induce opioid withdrawal effects in people who are taking, or have recently used, opioid full agonists, the ...
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Receptor Antagonist
A receptor antagonist is a type of receptor ligand or drug that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it like an agonist. Antagonist drugs interfere in the natural operation of receptor proteins.Pharmacology Guide: In vitro pharmacology: concentration-response curves
" '' GlaxoWellcome.'' Retrieved on December 6, 2007.
They are sometimes called blockers; examples include alpha blockers,

Sedative
A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are CNS depressants and interact with brain activity causing its deceleration. Various kinds of sedatives can be distinguished, but the majority of them affect the neurotransmitter gamma-aminobutyric acid (GABA). In spite of the fact that each sedative acts in its own way, most produce relaxing effects by increasing GABA activity. This group is related to hypnotics. The term ''sedative'' describes drugs that serve to calm or relieve anxiety, whereas the term ''hypnotic'' describes drugs whose main purpose is to initiate, sustain, or lengthen sleep. Because these two functions frequently overlap, and because drugs in this class generally produce dose-dependent effects (ranging from anxiolysis to loss of consciousness) they are often referred to collectively as ''sedative-hypnotic'' drugs. Sedatives can be used to produce an overly-calming effect ( alcohol being the m ...
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Buprenorphine
Buprenorphine is an opioid used to treat opioid use disorder, acute pain, and chronic pain. It can be used under the tongue (sublingual), in the cheek (buccal), by injection (intravenous and subcutaneous), as a skin patch (transdermal), or as an implant. For opioid use disorder, it is typically started when withdrawal symptoms have begun and for the first two days of treatment under direct observation of a health-care provider. In the United States, the combination formulation of buprenorphine/naloxone (Suboxone) is usually prescribed to discourage misuse by injection. Maximum pain relief is generally within an hour with effects up to 24 hours. Buprenorphine affects different types of opioid receptors in different ways. Depending on the type of receptor, it may be an agonist, partial agonist, or antagonist. In the treatment of opioid use disorder buprenorphine is an agonist/antagonist, meaning that it relieves withdrawal symptoms from other opioids and induces some e ...
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Methadone
Methadone, sold under the brand names Dolophine and Methadose among others, is a synthetic opioid agonist used for chronic pain and also for opioid dependence. It is used to treat chronic pain, and it is also used to treat addiction to heroin or other opioids. Prescribed for daily use, the medicine relieves cravings and removes withdrawal symptoms. Detoxification using methadone can be accomplished in less than a month, or it may be done gradually over as long as six months. While a single dose has a rapid effect, maximum effect can take up to five days of use. The pain-relieving effects last about six hours after a single dose. After long-term use, in people with normal liver function, effects last 8 to 36 hours. Methadone is usually taken by mouth and rarely by injection into a muscle or vein. Side effects are similar to those of other opioids. These frequently include dizziness, sleepiness, vomiting, and sweating. Serious risks include opioid abuse and respiratory depre ...
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Anxiety
Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat whereas the latter is defined as the emotional response to a real threat. It is often accompanied by nervous behavior such as pacing back and forth, somatic complaints, and rumination. Anxiety is a feeling of uneasiness and worry, usually generalized and unfocused as an overreaction to a situation that is only subjectively seen as menacing. It is often accompanied by muscular tension, restlessness, fatigue, inability to catch one's breath, tightness in the abdominal region, nausea, and problems in concentration. Anxiety is closely related to fear, which is a response to a real or perceived immediate threat (fight or flight response); anxiety involves the expectation of future threat including dread. People facing anxiety may withdraw fro ...
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Depression (mood)
Depression is a mental state of low mood and aversion to activity, which affects more than 280 million people of all ages (about 3.5% of the global population). Classified medically as a mental and behavioral disorder, the experience of depression affects a person's thoughts, behavior, motivation, feelings, and sense of well-being. The core symptom of depression is said to be anhedonia, which refers to loss of interest or a loss of feeling of pleasure in certain activities that usually bring joy to people. Depressed mood is a symptom of some mood disorders such as major depressive disorder and dysthymia; it is a normal temporary reaction to life events, such as the loss of a loved one; and it is also a symptom of some physical diseases and a side effect of some drugs and medical treatments. It may feature sadness, difficulty in thinking and concentration and a significant increase or decrease in appetite and time spent sleeping. People experiencing depression may have ...
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Post Acute Withdrawal Syndrome
Post-acute withdrawal syndrome (PAWS) is a hypothesized set of persistent impairments that occur after withdrawal from alcohol, opiates, benzodiazepines, antidepressants, and other substances. Infants born to mothers who used substances of dependence during pregnancy may also experience a post-acute withdrawal syndrome. While post-acute withdrawal syndrome has been reported by those in the recovery community, there have been few scientific studies supporting its existence outside of protracted benzodiazepine withdrawal. Because of this, the disorder is not recognized by the ''Diagnostic and Statistical Manual of Mental Disorders'' or major medical associations. Drug use, including alcohol and prescription drugs, can induce symptomatology which resembles mental illness. This can occur both in the intoxicated state and during the withdrawal state. In some cases these substance-induced psychiatric disorders can persist long after detoxification from amphetamine, cocaine, opioid, a ...
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Homeostasis
In biology, homeostasis (British English, British also homoeostasis) Help:IPA/English, (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physics, physical, and chemistry, chemical conditions maintained by organism, living systems. This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits (homeostatic range). Other variables include the pH of extracellular fluid, the concentrations of sodium, potassium and calcium ions, as well as that of the blood sugar level, and these need to be regulated despite changes in the environment, diet, or level of activity. Each of these variables is controlled by one or more regulators or homeostatic mechanisms, which together maintain life. Homeostasis is brought about by a natural resistance to change when already in the optimal conditions, and equilibrium is maintained by many regulatory mechanisms: it is thought to be ...
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Low-dose Naltrexone
Low-dose naltrexone describes the off-label, experimental use of the medication naltrexone at low doses for diseases such as Crohn's disease and multiple sclerosis. Naltrexone is typically prescribed for opioid dependence or alcohol dependence, as it is a strong opioid antagonist. It has been suggested that low-dose naltrexone might operate as an anti-inflammatory agent and therefore could be used to treat some chronic conditions involving immune system dysregulation. Anecdotal reports have suggested that low-dose naltrexone may be effective in treating a wide range of diseases, including cancer, chronic Lyme Disease, chronic fatigue syndrome HIV/AIDS, fibromyalgia patients, arthritis, and immunity for immunosuppressed patients. Its use is increasing due to its anti-inflammatory properties and minimal side effects. LDN's mechanism of action (if any) is still incompletely understood. Mechanism of action Action of naltrexone at normal dose Naltrexone and its active metabolite 6- ...
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Opioid Addiction
Opioid use disorder (OUD) is a substance use disorder characterized by cravings for opioids, continued use despite physical and/or psychological deterioration, increased tolerance with use, and withdrawal symptoms after discontinuing opioids. Opioid withdrawal symptoms include nausea, muscle aches, diarrhea, trouble sleeping, agitation, and a low mood. Addiction and dependence are important components of OUD. Risk factors for OUD include a history of opioid misuse, current opioid misuse, young age, socioeconomic status, race, untreated psychiatric disorders, and environments that promote misuse (social, family, professional, etc.). Complications may include opioid overdose, suicide, HIV/AIDS, hepatitis C, and problems meeting social or professional responsibilities. Diagnosis may be based on criteria by the American Psychiatric Association in the DSM-5. If more than two of 11 criteria are present during a year, the diagnosis is said to be present. Opioids include substances suc ...
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Antidote
An antidote is a substance that can counteract a form of poisoning. The term ultimately derives from the Greek term φάρμακον ἀντίδοτον ''(pharmakon) antidoton'', "(medicine) given as a remedy". Antidotes for anticoagulants are sometimes referred to as reversal agents. The antidotes for some particular toxins are manufactured by injecting the toxin into an animal in small doses and extracting the resulting antibodies from the host animals' blood. This results in an antivenom that can be used to counteract venom produced by certain species of snakes, spiders, and other venomous animals. Some animal venoms, especially those produced by arthropods (such as certain spiders, scorpions, and bees) are only potentially lethal when they provoke allergic reactions and induce anaphylactic shock; as such, there is no "antidote" for these venoms; however anaphylactic shock can be treated (e.g. with epinephrine). Some other toxins have no known antidote. For example, the pois ...
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μ-opioid Receptor
The μ-opioid receptors (MOR) are a class of opioid receptors with a high affinity for enkephalins and beta-endorphin, but a low affinity for dynorphins. They are also referred to as μ(''mu'')-opioid peptide (MOP) receptors. The prototypical μ-opioid receptor agonist is morphine, the primary psychoactive alkaloid in opium. It is an inhibitory G-protein coupled receptor that activates the Gi alpha subunit, inhibiting adenylate cyclase activity, lowering cAMP levels. Structure The structure of the μ-opioid receptor has been determined with the antagonist β-FNA, the agonist BU72, and in a complex with DAMGO and Gi protein. Splice variants Three variants of the μ-opioid receptor are well characterized, though RT-PCR has identified up to 10 total splice variants in humans. Location They can exist either presynaptically or postsynaptically depending upon cell types. The μ-opioid receptors exist mostly presynaptically in the periaqueductal gray region, and in the superfi ...
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