Known brand names include MS Contin, Kadian, Duramorph, Infumorph, and Mitigo.
A strong opioid pain reliever given by injection in the hospital or as tablets, for pain severe enough that other treatments are not enough. It can slow or stop breathing and can cause addiction.
Morphine attaches mainly to mu-opioid receptors, which are found throughout the brain and spinal cord. Switching these receptors on eases pain and changes how the brain and nerves respond to it, though the exact way it relieves pain is not known. It also acts directly on the breathing center in the brain stem, making it less responsive to rising carbon dioxide, so breathing slows. In the gut it slows the movement of food and stool while tightening the bowel muscle, which leads to constipation.
Injected into a muscle, it starts easing pain within 5 to 20 minutes and usually lasts three to four hours, and the tablets give their strongest relief about an hour after a dose. Higher doses keep giving more pain relief with no ceiling, but they also slow breathing and alertness more, which is what limits how much can be given safely. It also widens blood vessels, so people may feel dizzy or faint on standing and may notice itching, flushing, or sweating. It shrinks the pupils, and tiny pupils are one sign of an overdose.
Morphine is a strong opioid pain reliever for pain severe enough to need an opioid when other treatments fall short. The injection is used for this kind of severe pain. The immediate-release tablets treat both short-term severe pain and long-lasting severe pain. The goal is to keep pain under control, and the dose is adjusted to balance relief against side effects.
The injection is given into a vein or a muscle, and the tablets are taken by mouth. The tablets are for adults, and for children who weigh at least 50 kg only when the pain is short-term. It is kept for people whose pain is not controlled by other options or who cannot take them, because addiction, misuse, overdose, and death can happen at any dose and at any point in treatment. The tablets have not been shown to be safe and effective for long-lasting pain in children.
Sleepiness, dizziness, nausea, vomiting, sweating, and constipation are what people notice most, and the constipation can be severe. The label treats slowed or stopped breathing as the main danger. It also warns about very low blood pressure, addiction and misuse, pain that gets worse instead of better, adrenal problems, and spasms that worsen gallbladder or pancreas disease.
This is the boxed warning, the warning the FDA label prints first.
Serious and life-threatening risks: addiction, abuse, and misuse that can lead to overdose and death; life-threatening respiratory depression, highest at the start and after dose increases; profound sedation, respiratory depression, coma, and death with benzodiazepines, alcohol, or other CNS depressants; and neonatal opioid withdrawal syndrome after prolonged use in pregnancy.