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Morphine

Morphine is the principal medical alkaloid of opium. Its effects are pain relief, euphoria, dependence potential, and respiratory depression. It also binds with k-receptors mediating spinal analgesia, miosis, and sedation.

Morphine is the drug of choice for the treatment of severe acute or chronic pain, used mostly for acute pain (myocardial infarction, multiple injuries, post-operative). Morphine is also frequently injected to prepare for surgery and it can also be given during the operation for the suppression of nociceptive stimuli.

For long-term treatment of terminally ill, pain-ridden patients, oral preparations are usually better suited. For this, regular administration of individually-adjusted doses is decisive. Morphine can be combined with other (non-opioid) analgesics or psychotropic drugs. For subjects with refractory pain, the epidural (or intrathecal) injection or infusion of morphine can be considered. This treatment is frequently efficacious but it is associated with considerable risks. It should therefore only be performed by specially trained staff.

Side Effects: Morphine causes a wide range of side-effects. Severe reactions such as respiratory depressions and pronounced hypotension are uncommon when the drug is used therapeutically. Drop in blood pressure due to a cardiac infarction or hypovolemia can have dangerous results.

Constipation is the most important problem in long-term treatment. Initially sedation and nausea are present.

Even therapeutic doses can reduce respiratory frequency and can cause urinary retention. Further potential side-effects are euphoria and dysphoria, anxiety, itching, hives, bronchospasms, gas, headaches and contraction of the muscle of the iris, causing the pupil of the eye to become smaller. Development of tolerance to morphine entails ever-increasing doses. Infomed Drug Guide

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