The long-term effects of morphine

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Morphine is a opiate (narcotic) analgesic painkiller that changes the way your body processes pain. Usually available in pill or injection-ready formulations, morphine is still one of the most effective painkillers in medical use today, and is often prescribed for long-term use for people suffering from chronic pain.

Long-term use of morphine produces many effects on the brain and body. Understanding what these effects are is essential before considering morphine use over the long term.


A potent narcotic, morphine is usually given only in temporary situations of extreme pain, such as hospitalisation after an injury or for terminal illness pain control. Morphine is prescribed long term for chronic, debilitating pain--often associated with back problems such as a herniated disk--that interferes with a person's quality of life.

As a painkiller, morphine affects the central nervous system, triggering the brain's reward system to relieve pain, states the Narconon website. However, morphine's effects on the brain very quickly become habit forming, so the drug's function itself produces one of its many long term effects of addiction.

General Long-Term Effects

Other effects that persist over long-term use of morphine are the drug's primary side effects. Aside from relieving pain, morphine produces a host of psychological and physical side effects that are important to be aware of.

Persistent side-effects of morphine include mental impairment, euphoria, decreased appetite, reduction of physical performance, chronic constipation, and reduced or eliminated sex drive. Sleepiness or slurred speech are also to be expected when taking morphine for a long period of time, according to Medline Plus.

Effects on Men

Morphine's long-term effects previously mentioned are common to both men and women; however, studies suggest that long-term use has gender-specific effects.

For men, long-term use of morphine has notable health considerations. An April 1998 study by the Department of Psychiatry at Washington University School of Medicine reports that morphine use suppress certain actions of the pituitary gland in men which affects the production of testosterone. This results in lower levels of testosterone in men taking morphine over long periods of time.

Effects on Women

Women have certain things to consider regarding long-term morphine use as well. Again, morphine causes hormonal changes in the body and brain, and this has gender-specific implications for women as well as men.

According to Narconon, morphine may interfere with the menstrual cycle, which presents a variety of fertility issues and health concerns. Additionally, long-term use of morphine poses a serious problem for women wishing to have children, since morphine crosses the placental barrier. Unfortunately, this means that a mother dependent upon morphine passes on morphine dependence to her child.


Dependence on morphine is one of the most serious side-effects of long-term use of the drug, since potentially severe withdrawals can occur if morphine use is suddenly stopped. The U.S. National Institute of Health states that long-term morphine even affects the size and shape of the very receptors the drug binds to in the brain, resulting in increased dependence over long periods of time.

Symptoms of morphine withdrawal can be very unpleasant, and may include runny nose, nausea, vomiting, and clamminess to the far worse stroke, heart attack and even death.


It is important to talk to your doctor carefully about the long-term effects of morphine before beginning such a treatment. If you are using morphine without a prescription, it is also vital to speak with a health care professional about the drug's long-term effects. Knowing what to expect from long-term use of morphine may affect your decision to continue the drug for extended periods, per