Morfine

Morfine, also known as morphine, is a potent opioid analgesic derived from opium. It is one of the oldest and most widely used medicines for severe pain and serves as a standard reference drug in opioid pharmacology. Morfine is a naturally occurring alkaloid of Papaver somniferum and acts primarily as a mu-opioid receptor agonist in the central nervous system, altering pain perception and emotional response to pain. It also induces sedation and, in some cases, euphoria and dampened visceral sensations.

Medical use centers on the treatment of moderate to severe acute and chronic pain, including cancer-related pain, post-surgical pain, and palliative care. It is administered through multiple routes, such as oral, subcutaneous, intramuscular, intravenous, rectal, and in specialized settings, epidural or intrathecal infusion. Extended-release formulations provide longer-lasting analgesia.

Pharmacokinetics involve good oral absorption with significant first-pass metabolism. The liver glucuronidates morfine to morphine-3-glucuronide and morphine-6-glucuronide, with the metabolites excreted mainly by the kidneys. The active metabolite morphine-6-glucuronide can contribute to analgesia, particularly with renal impairment.

Common adverse effects include constipation, nausea, vomiting, drowsiness, and respiratory depression. Tolerance, physical dependence, and the potential for misuse require careful prescribing, patient monitoring, and diagnostics for overdose. Naloxone is used as an antidote in emergencies.

Historically, morfine was isolated in 1804 by Friedrich Sertürner (often cited as Serturner). Today it remains a controlled substance with strict regulatory requirements in many countries. See also opioids and analgesics.