Immediate release morphine is beneficial in reducing the symptom of acute shortness of breath due to both cancer and non-cancer causes. In the setting of breathlessness at rest or on minimal exertion from conditions such as advanced cancer or end-stage cardio-respiratory diseases, regular, low-dose sustained release morphine significantly reduces breathlessness safely, with its benefits maintained over time.
Its duration of analgesia is about 3–4 hours when administered via the intravenous, subcutaneous, or intramuscular route and 3–6 hours when given by mouth. Morphine is also used in slow release formulations for opiate substitution therapy (OST) in Austria, Bulgaria, and Slovenia, for addicts who cannot tolerate the side effects of using either methadone or buprenorphine, or for addicts who are «not held» by buprenorphine or methadone. It is used for OST in many parts of Europe although on a limited basis.
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 increased 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.
Morphine is a potentially highly addictive substance. It can cause psychological dependence and physical dependence as well as tolerance. In the presence of pain and the other disorders for which morphine is indicated, 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.
In controlled studies comparing the physiological and subjective effects of 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. The choice of heroin and morphine over other opioids by former-drug addicts may also be the result of the fact that heroin (also known as morphine diacetate, diamorphine or di-acetyl-morphine) is an ester of morphine and a morphine prodrug, essentially meaning that they are identical drugs in vivo. Heroin is converted to morphine before binding to the opioid receptors in the brain and spinal cord, where morphine then causes the subjective effects, which is what the addicted individuals are ultimately looking for.
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, and areas for privacy. More recent research has shown that an enriched environment may decrease morphine addiction in mice.
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, 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 ome 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 have potential to 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.
Medicine (also called conventional, orthodox, scientific, or mainstream medicine, especially in connection with alternative medicine, UK English Listeni/ˈmɛdsɨn/, US English Listeni/ˈmɛdɨsɨn/) is the field of applied science related to the art of healing by diagnosis, treatment, and prevention of disease. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness in human beings.
Contemporary medicine applies biomedical sciences, biomedical research, genetics and medical technology to diagnose, treat, and prevent injury and disease, typically through medication or surgery, but also through therapies as diverse as psychotherapy, external splints & traction, prostheses, biologics, pharmaceuticals, ionizing radiation among others.
The word medicine is derived from the Latin ars medicina, meaning the art of healing.