Morphine Side Effects

Morphine relieves pain, but it also causes concerning side effects. Low doses may cause dizziness and drowsiness. High doses are associated with vomiting and trouble breathing. Overdoses can be fatal, and long-term use can lead to addiction and other health issues.
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Morphine effectively treats short-term pain. But it also causes unpleasant or inconvenient side effects. When used as prescribed by a doctor, the short-term benefits of morphine outweigh the negative effects of the drug.

However, the long-term benefits of the drug are unknown. Regular morphine use can cause a range of health problems. Misusing morphine to get high is associated with numerous side effects, including addiction, withdrawal and overdose.

Short-Term Side Effects of Morphine

Most people feel the initial effects of morphine within 15 minutes of swallowing an immediate-release pill. The effects of a morphine injection occur more quickly.

Morphine stays in your system for up to three days, but the effects of a regular dose of the drug fade within three to six hours. Extended-release versions of the drug may last up to 12 hours. The side effects of morphine generally last a similar amount of time.

Short-term side effects of morphine include:

A small number of people have reported allergic reactions to morphine injections. Allergic reactions included skin rashes, hives and itching, according to the drug’s label.

The severity of the side effects depends on the dose, method of use and the person’s tolerance. Tolerance is the body’s natural response to repeated use of a drug. As tolerance increases, the body requires higher doses to feel a drug’s effects.

Misusing morphine increases the risk of severe side effects. Morphine misuse refers to using the drug in any manner other than the way prescribed by a doctor.

Long-Term Side Effects of Morphine

Constipation and gastrointestinal problems are two of the most common long-term side effects of morphine. Opioid-induced constipation has become so prevalent that pharmaceutical companies have developed medications to treat it.

Other long-term effects stem from the way the body adapts to repeated exposure to the drug. Tolerance and dependence develop in every person who takes morphine regularly. The brain gets used to the presence of morphine, and it becomes less sensitive to the drug’s effects.

The brain starts to rely on morphine to feel normal. When someone who has taken morphine for several days quits taking it, they experience withdrawal. Morphine withdrawal symptoms include diarrhea, muscle pain and irritability.

Withdrawal symptoms can drive continued morphine use. Using morphine to avoid withdrawal is a warning sign for morphine addiction.

Addiction occurs when a person uses a drug regardless of negative consequences. Few people who use morphine for the short-term treatment of pain become addicted. Long-term use and misuse increase the risk of addiction.

Morphine Overdose Symptoms

Misusing morphine increases the risk of overdose. Morphine overdoses can be deadly. The drug can make you pass out and stop breathing.

The risk of overdose increases if you take doses higher than prescribed, take the drug more often than prescribed or use morphine purchased on the street. Using the drug in risky ways, such as injecting or smoking it, also increases the risk of overdose.

Morphine overdose symptoms include:

A medication called naloxone can reverse the effects of a morphine overdose. The medication is sold under the brand names Narcan and Evzio. However, naloxone is not a substitute for medical care.

If someone overdoses on morphine:

Even if you survive an overdose, you can experience serious health problems. Health care providers can treat some side effects of an overdose and limit the amount of long-term health problems caused by the overdose.

Signs of Morphine Addiction

An overdose is a warning sign for prescription drug addiction. Continuing to misuse morphine after an overdose is a red flag. People who are addicted to a drug are unable to stop using the drug on their own. They need professional treatment from health providers and support from friends and family.

Signs of morphine addiction include:

People who are addicted to morphine may not recognize issues caused by the drug. They may not be willing to quit using the drug, or they may not think they can stop.

Opioid addiction treatment teaches these people to live without morphine. If people addicted to the drug don’t go to rehab, they risk experiencing an overdose on a daily basis. Morphine is safe and effective for the short-term treatment of pain, but misuse and long-term use is hazardous.

Medical Disclaimer: aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.

Chris Elkins, MA
Senior Content Writer,
Chris Elkins worked as a journalist for three years and was published by multiple newspapers and online publications. Since 2015, he’s written about health-related topics, interviewed addiction experts and authored stories of recovery. Chris has a master’s degree in strategic communication and a graduate certificate in health communication.
Kim Borwick, MA

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