Morphine (INN) (pronounced /ˈmɔrfiːn/) is a highly potent opiate analgesic drug, is the principal active agent in opium, and is considered to be the prototypical opioid. Like other opioids, e.g. oxycodone, hydromorphone, and diacetylmorphine (heroin), morphine acts directly on the central nervous system (CNS) to relieve pain. Morphine has a high potential for addiction; tolerance and both physical and psychological dependence develop rapidly.

History
An ampoule of morphine with integral needle for immediate use. From WWII. On display at the Army Medical Services Museum.Morphine was discovered as the first active alkaloid extracted from a plant in 1803 and first marketed to the general public by Sertürner and company in 1817. It was marketed for analgesia, and as a "cure" for opium and alcohol addiction. Later it was found out that morphine was even more addictive than either alcohol or opium, and its extensive use during the American Civil War allegedly resulted in over 400,000 sufferers from the "soldier's disease" of morphine addiction. This idea has been a subject of controversy, as there have been suggestions that such a disease was in fact a hoax.

Diacetylmorphine (better known as heroin) was synthesized from morphine in 1874 and brought to market by Bayer in 1898. Heroin is approximately 1.5–2 times more potent than morphine on a milligram-for-milligram basis. Using a variety of subjective and objective measures, one study estimated the relative potency of heroin to morphine administered intravenously to post-addicts to be 1.80–2.66 mg of morphine sulfate to 1 mg of diamorphine hydrochloride (heroin).

Morphine became a controlled substance in the U.S. under the Harrison Narcotics Tax Act of 1914, and possession without a prescription in the U.S. is a criminal offense. Morphine was the most commonly abused narcotic analgesic in the world up until heroin was synthesized and came into use. Until the synthesis of dihydromorphine (c.a. 1900), the dihydromorphinone class of opioids (1920s), and oxycodone (1916) and similar drugs, there generally were no other drugs in the same efficacy range as opium, morphine and heroin, with synthetics still several years away (pethidine was invented in Germany in 1937) and opioid agonists amongst the semi-synthetics were analogues and derivatives of codeine such as dihydrocodeine (Paracodin), ethylmorphine (Dionine), and benzylmorphine (Peronine). Even today, morphine is the most sought after prescription narcotic by heroin addicts when heroin is scarce, all other things being equal; local conditions and user preference may cause hydromorphone, oxymorphone, high-dose oxycodone, or methadone as well as dextromoramide in specific instances such as 1970s Australia, to top that particular list. The stop-gap drugs used by the largest absolute number of heroin addicts is probably codeine, with significant use also of dihydrocodeine, poppy straw derivatives like poppy pod and poppy seed tea, propoxyphene, and tramadol

The structural formula of morphine was determined by 1925. At least three methods of total synthesis of morphine from starting materials such as coal tar and petroleum distillates have been patented, the first of which was announced in 1952, by Dr. Marshall D. Gates, Jr at the University of Rochester. Still, the vast majority of morphine is derived from the opium poppy by either the traditional method of gathering latex from the scored unripe pods of the poppy, or processes using poppy straw, the dried pods and stems of the plant, the most widespread of which was invented in Hungary in 1925 and announced in 1930 by chemist János Kábay.

Morphine, which was the first active principle chemically isolated from any plant, was first isolated in 1803 in Paderborn, Germany, by the German pharmacist Friedrich Wilhelm Adam Sertürner, who named it morphium after Morpheus, the Greek god of dreams. But it was not until the development of the hypodermic needle in 1853 that its use spread, especially during the Austro-Prussian and Franco-Prussian Wars starting in 1866 and 1871 respectively.

Indications
Morphine can be used:

as an analgesic in hospital settings to relieve
pain in myocardial infarction
pain in sickle cell crisis
pain associated with surgical conditions, pre- and postoperatively
pain associated with trauma
in the relief of severe chronic pain, e.g.,
cancer
pain from kidney stones (renal colic, ureterolithiasis)
severe back pain
as an adjunct to general anesthesia
in epidural anesthesia or intrathecal analgesia
for palliative care (i.e., to alleviate pain without curing the underlying reason for it, usually because the latter is found impossible)
as an antitussive for severe cough
in nebulized form, for treatment of dyspnea, although the evidence for efficacy is slim. Evidence is better for other routes.
as an antidiarrheal in chronic conditions (e.g., for diarrhea associated with AIDS, although loperamide (a non-absorbed opioid acting only on the gut) is the most commonly used opioid for diarrhea).

Side-effects

Constipation
Like loperamide and other opioids, morphine acts on the myenteric plexus in the intestinal tract, reducing gut motility, causing constipation. The gastrointestinal effects of morphine are mediated primarily by μ-opioid receptors in the bowel. By inhibiting gastric emptying and reducing propulsive peristalsis of the intestine, morphine decreases the rate of intestinal transit. Reduction in gut secretion and increases in intestinal fluid absorption also contribute to the constipating effect. Opioids also may act on the gut indirectly through tonic gut spasms after inhibition of nitric oxide generation. This effect was shown in animals when a nitric oxide precursor, L-Arginine, reversed morphine-induced changes in gut motility.


Addiction
In controlled studies comparing the physiological and subjective effects of injected heroin and morphine in individuals formerly addicted to opiates, subjects showed no preference for one drug over the other. Equipotent, injected doses had comparable action courses, with no difference in subjects' self-rated feelings of euphoria, ambition, nervousness, relaxation, drowsiness, or sleepiness. Short-term addiction studies by the same researchers demonstrated that tolerance developed at a similar rate to both heroin and morphine. When compared to the opioids hydromorphone, fentanyl, oxycodone, and pethidine/meperidine, former addicts showed a strong preference for heroin and morphine, suggesting that heroin and morphine are particularly susceptible to abuse and addiction. Morphine and heroin were also much more likely to produce euphoria and other positive subjective effects when compared to these other opioids.

Other studies such as the Rat Park experiments suggest that morphine is less physically addictive than others suggest, and most studies on morphine addiction merely show that "severely distressed animals, like severely distressed people, will relieve their distress pharmacologically if they can."  In these studies rats with a morphine "addiction" overcome their addiction themselves when placed in decent living environments with enough space, good food, companionship, areas for exercise, areas for privacy. More recent research has shown that an enriched environment may decrease morphine addiction in mice.


Morphine is a potentially highly addictive substance, as it can cause psychological dependence and physical dependence as well as tolerance, with an addiction potential identical to that of heroin. When used illicitly, a very serious narcotic habit can develop in a matter of weeks whereas iatrogenic morphine addiction rates have, according to a number of studies, remained nearly constant at one case in 150 to 200 for at least two centuries. In the presence of pain and the other disorders for which morphine is indicated for use, a combination of psychological and physiological factors tend to prevent true addiction from developing, although physical dependence and tolerance will develop with protracted opioid therapy, and these two factors do not add up to addiction without psychological dependence which manifests primarily as a morbid seek orientation for the drug.

Tolerance
Tolerance to the analgesic effects of morphine is fairly rapid. There are several hypotheses about how tolerance develops, including opioid receptor phosphorylation (which would change the receptor conformation), functional decoupling of receptors from G-proteins (leading to receptor desensitization), mu-opioid receptor internalization and/or receptor down-regulation (reducing the number of available receptors for morphine to act on), and upregulation of the cAMP pathway (a counterregulatory mechanism to opioid effects) (For a review of these processes, see Koch and Hollt.


Withdrawal symptoms
The withdrawal symptoms associated with morphine addiction are usually experienced shortly before the time of the next scheduled dose, sometimes within as early as a few hours (usually between 6–12 hours) after the last administration. Early symptoms include watery eyes, insomnia, diarrhea, runny nose, yawning, dysphoria, and sweating and in some cases a strong drug craving. Severe headache, restlessness, irritability, loss of appetite, body aches, severe abdominal pain, nausea and vomiting, tremors, and even stronger and more intense drug craving appear as the syndrome progresses. Severe depression and vomiting are very common. During the acute withdrawal period systolic and diastolic blood pressure increase, usually beyond pre-morphine levels, and heart rate increases, which could potentially cause a heart attack, blood clot, or stroke. Chills or cold flashes with goose bumps ("cold turkey") alternating with flushing (hot flashes), kicking movements of the legs ("kicking the habit") and excessive sweating are also characteristic symptoms. Severe pains in the bones and muscles of the back and extremities occur, as do muscle spasms. At any point during this process, a suitable narcotic can be administered that will dramatically reverse the withdrawal symptoms. Major withdrawal symptoms peak between 48 and 96 hours after the last dose and subside after about 8 to 12 days. Sudden withdrawal by heavily dependent users who are in poor health is very rarely fatal. Morphine withdrawal is considered less dangerous than alcohol, barbiturate, or benzodiazepine withdrawal.

The psychological dependence associated with morphine addiction is complex and protracted. Long after the physical need for morphine has passed, the addict will usually continue to think and talk about the use of morphine (or other drugs) and feel strange or overwhelmed coping with daily activities without being under the influence of morphine. Psychological withdrawal from morphine is a very long and painful process. Addicts often suffer severe depression, anxiety, insomnia, mood swings, amnesia (forgetfulness), low self-esteem, confusion, paranoia, and other psychological disorders. The psychological dependence on morphine can, and usually does, last a lifetime. There is a high probability that relapse will occur after morphine withdrawal when neither the physical environment nor the behavioral motivators that contributed to the abuse have been altered. Testimony to morphine's addictive and reinforcing nature is its relapse rate. Abusers of morphine (and heroin), have one of the highest relapse rates among all drug users.



Effects on the immune system
Morphine has long been known to act on receptors expressed on cells of the central nervous system resulting in pain relief and analgesia. In the 1970s and '80s, evidence suggesting that opiate drug addicts show increased risk of infection (such as increased pneumonia, tuberculosis, and HIV) led scientists to believe that morphine may also affect the immune system. This possibility increased interest in the effect of chronic morphine use on the immune system.

The first step of determining that morphine may affect the immune system was to establish that the opiate receptors known to be expressed on cells of the central nervous system are also expressed on cells of the immune system. One study successfully showed that dendritic cells, part of the innate immune system, display opiate receptors. Dendritic cells are responsible for producing cytokines, which are the tools for communication in the immune system. This same study showed that dendritic cells chronically treated with morphine during their differentiation produce more interleukin-12 (IL-12), a cytokine responsible for promoting the proliferation, growth, and differentiation of T-cells (another cell of the adaptive immune system) and less interleukin-10 (IL-10), a cytokine responsible for promoting a B-cell immune response (B cells produce antibodies to fight off infection).

This regulation of cytokines appear to occur via the p38 MAPKs (mitogen activated protein kinase) dependent pathway. Usually, the p38 within the dendritic cell expresses TLR 4 (toll-like receptor 4), which is activated through the ligand LPS (lipopolysaccharide). This causes the p38 MAPK to be phosphorylated. This phosphorylation activates the p38 MAPK to begin producing IL-10 and IL-12. When the dendritic cell is chronically exposed to morphine during their differentiation process then treated with LPS, the production of cytokines is different. Once treated with morphine, the p38 MAPK does not produce IL-10, instead favoring production of IL-12. The exact mechanism through which the production of one cytokine is increased in favor over another is not known. Most likely, the morphine causes increased phosphorylation of the p38 MAPK. Transcriptional level interactions between IL-10 and IL-12 may further increase the production of IL-12 once IL-10 is not being produced. Future research may target the exact mechanism that increases the production of IL-12 in morphine treated dendritic cells. This increased production of IL-12 causes increased T-cell immune response. This response is due to the ability of IL-12 to cause T helper cells to differentiate into the Th1 cell, causing a T cell immune response.

Further studies on the effects of morphine on the immune system have shown that morphine influences the production of neutrophils and other cytokines. Since cytokines are produced as part of the immediate immunological response (inflammation), it has been suggested that they may also influence pain. In this way, cytokines may be a logical target for analgesic development. Recently, one study has used an animal model (hind-paw incision) to observe the effects of morphine administration on the acute immunological response. Following hind-paw incision, pain thresholds and cytokine production were measured. Normally, cytokine production in and around the wounded area increases in order to fight infection and control healing (and, possibly, to control pain), but pre-incisional morphine administration (0.1-10.0 mg/kg) reduced the number of cytokines found around the wound in a dose-dependent manner. The authors suggest that morphine administration in the acute post-injury period may reduce resistance to infection and may impair the healing of the wound.



Salt or drug CSA schedule ACSCN Free base conversion ratio
Morphine II 9300 1
Morphine acetate II 9300 0.71
Morphine citrate II 9300 0.81
Morphine bitartrate II 9300 0.66
Morphine stearate II 9300 0.51
Morphine phthalate II 9300 0.89
Morphine hydrobromide II 9300 0.78
Morphine hydrobromide (2 H2O) II 9300 0.71
Morphine hydrochloride II 9300 0.89
Morphine hydrochloride (3 H2O) II 9300 0.76
Morphine hydriodide (2 H2O) II 9300 0.64
Morphine lactate II 9300 0.76
Morphine monohydrate II 9300 0.94
Morphine meconate (5 H2O) II 9300 0.66
Morphine mucate II 9300 0.57
Morphine nitrate II 9300 0.82
Morphine phosphate (1/2 H2O) II 9300 0.73
Morphine phosphate (7 H2O) II 9300 0.73
Morphine salicylate II 9300
Morphine phenylpropionate II 9300 0.65
Morphine methyliodide II 9300 0.67
Morphine isobutyrate II 9300 0.76
Morphine hypophosphite II 9300 0.81
Morphine sulfate (5 H2O) II 9300 0.75
Morphine tannate II 9300
Morphine tartrate (3 H2O) II 9300 0.74
Morphine valerate II 9300 0.74
Morphine methylbromide I 9305 0.75
Morphine methylsulfonate I 9306 0.75
Morphine-N-oxide I 9307 1
Morphine-N-oxide quinate I 9307 0.60
Pseudomorphine I not mentioned

Illicit use
The euphoria, comprehensive alleviation of distress and therefore all aspects of suffering, promotion of sociability and empathy, "body high", and anxiolysis provided by narcotic drugs including the opioids can cause the use of high doses in the absence of pain for a protracted period, which can impart a morbid craving for the drug in the user. Being the prototype of the entire opioid class of drugs means that morphine has properties that may lend it to misuse. Morphine addiction is the model upon which the current perception of addiction is based.

Animal and human studies and clinical experience back up the contention that morphine is one of the most euphoric of drugs, and via all but the IV route heroin and morphine cannot be distinguished according to studies. Chemical changes to the morphine molecule yield other powerful euphorigenics such as dihydromorphine, hydromorphone (Dilaudid®, Hydal®) and oxymorphone (Numorphan®, Opana®) as well as the latter three's methylated equivalents dihydrocodeine, hydrocodone and oxycodone respectively; in addition to heroin, there are dipropanoylmorphine, diacetyldihydromorphine and other members of the 3,6 morphine diester category like nicomorphine and other similar semi-synthetic opiates like desomorphine, hydromorphinol &c. used clinically in many countries of the world but in many cases also produced illicitly in rare instances.

Misuse of morphine generally entails taking more than prescribed or outside of medical supervision, injecting oral formulations, mixing it with unapproved potentiators such as alcohol, cocaine, and the like, and/or defeating the extended-release mechanism by chewing the tablets or turning into a powder for snorting or preparing injectables. The latter method can be every bit as time-consuming and involved as traditional methods of smoking opium. This and the fact that the liver destroys a large percentage of the drug on the first pass impacts the demand side of the equation for clandestine re-sellers, as many customers are not needle users and may have been disappointed with ingesting the drug orally. As morphine is generally as hard or harder to divert than oxycodone in a lot of cases, morphine in any form is uncommon on the street, although ampoules and phials of morphine injection, pure pharmaceutical morphine powder, and soluble multi-purpose tablets are very popular where available.

Morphine is also available in a paste which is used in the production of heroin which can be smoked by itself or turned to a soluble salt and injected; the same goes for the penultimate products of the Kompot (Polish Heroin) and black tar processes. Poppy straw as well as opium can yield morphine of purity levels ranging from poppy tea to near-pharmaceutical grade morphine by itself or with all of the more than 50 other alkaloids. It also is the active narcotic ingredient in opium and all of its forms, derivatives, and analogues as well as forming from breakdown of heroin and otherwise being present in many batches of illicit heroin as the result of imcomplete acetylation.

Slang terms for morphine include M, Big M, Vitamin M, Miss Emma, morph, morpho, Murphy, cube, cube juice, White Nurse, Red Cross, mojo, hocus, 13, Number 13, mofo, unkie, happy powder, joy powder, first line, Aunt Emma, coby, em, emsel, morf, dope, glad stuff, goody, God's Medicine, God's Own Medicine, hard stuff, morfa, morphia, morphy, mud, sister, Sister Morphine, stuff, white stuff, white merchandise and others. MS-Contin and its equivalents in other countries are known as misties, blockbusters, and the 100 mg tablets as greys.

Precursor to other opioids, Phamaceutical Manufacturing Setting
Morphine is a precursor in the manufacture in a large number of opioids such as dihydromorphine, hydromorphone, nicomorphine, and heroin as well as codeine, which itself has a large family of semi-synthetic derivatives.Morphine is commonly treated with acetic anhydride and ignited to yield heroin.  The pharmacology of heroin and morphine is identical except the two acetyl groups increase the lipid solubility of the heroin molecule, causing it to cross the blood-brain barrier and enter the brain more rapidly. Once in the brain, these acetyl groups are removed to yield morphine, which causes the subjective effects of heroin. Thus, heroin may be thought of as a more rapidly acting form of morphine.

Precursor to other opioids, Underground & Illicit
Illicit morphine is rarely produced from codeine found in over the counter cough and pain medicines. This demethylation reaction is often performed using pyridine and hydrochloric acid.

Another source of illicit morphine comes from the extraction of morphine from extended release morphine products, such as MS-Contin. Morphine can be extracted from these products with simple extraction techniques to yield a morphine solution that can be injected. Alternatively, the tablets can be crushed and snorted, injected or swallowed, although this provides much less euphoria although retaining some of the extended-release effect and the extended-release property is why MS-Contin is used in some countries alongside methadone, dihydrocodeine, buprenorphine, dihydroetorphine, piritramide, levo-alpha-acetylmethadol (LAAM) and special 24-hour formulations of hydromorphone for maintenance and detoxification of those physically dependent on opioids.

Another means of using or misusing morphine is to use chemical reactions to turn it into heroin or another stronger opioid. Morphine can, using a technique reported in New Zealand (where the initial precursor is codeine) and elsewhere known as home-bake, be turned into what is usually a mixture of morphine, heroin, 3-monoacetylmorphine, 6-monoacetylmorphine, and codeine derivatives like acetylcodeine if the process is using morphine made from demethylating codeine by mixing acetic anhydride or acetyl chloride with the morphine and cooking it in an oven between 80 and 85°C for several hours.

Since heroin is one of a series of 3,6 diesters of morphine, it is possible to convert morphine to nicomorphine (Vilan®) using nicotinic anhydride, dipropanoylmorphine with propionic anhydride, dibutanoylmorphine and disalicyloylmorphine with the respective acid anhydrides. Glacial Acetic acid can be used to obtain a mixture high in 6-monoacetylmorphine, nicotinic acid (Vitamin B3) in some form would be precursor to 6-nicotinylmorphine, salicylic acid may yield the salicyoyl analogue of 6-MAM, and so on.

Homebake or other clandestinely-produced heroin produced from extended-release morphine tablets may be known as Blue Heroin because of the blue colour of some of these tablets, even though the coloured coating of the tablet is usually removed before processing, many strengths of the tablets are not blue, bluish or a related colour like purple, and the final product tends not to be blue. A writer of a 2006 description of producing heroin from 100 mg as well as some 30 and 15 mg MS-Contin type tablets coined the term Blue Heroin to distinguish his, her or their product from New Zealand-style homebake as the process was shorter and began with uncoated tablets which in the case of the 100 mg tablet was at or above 35 per cent morphine sulphate by weight, resulting in a final liquid injectable which was brown-purple and quite potent. The drugs present in the final product are limited to heroin, 6-monoacetylmorphine, 3-monoacetylmorphine, and morphine, with the 6-MAM being just as or more sought than the heroin for reasons elucidated in the Wikipedia heroin article.

The clandestine conversion of morphine to ketones of the hydromorphone class or other derivatives like dihydromorphine (Paramorfan®), desomorphine (Permonid®), metopon &c. and codeine to hydrocodone (Dicodid®), dihydrocodeine (Paracodin®) &c. is more involved, time consuming, requires lab equipment of various types, and usually requires expensive catalysts and large amounts of morphine at the outset and is less common but still has been discovered by authorities in various ways during the last 20 years or so. Dihydromorphine can be acetylated into another 3,6 morphine diester, namely diacetyldihydromorphine (Paralaudin®), and hydrocodone into thebacon.
 

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