Morphine Effects: How Long Do They Last?
Depending on the type of morphine you take, the pain-relieving effects are felt quickly. Morphine injected straight into a vein is felt almost immediately.
Liquid morphine and morphine tablets typically begin working within 30 to 60 minutes and last for four to six hours. Slow-release morphine may take a day or longer to start working, but it also provides much longer-lasting pain relief.
Common side effects of morphine include the following:
- Dizziness or vertigo
- Itchy skin or rash
The more morphine you take, the more likely you are to experience unpleasant side effects. Serious side effects occur in less than one in 100 people, but they can include seizures, difficulty breathing, and serious allergic reactions. These should be addressed immediately with medical professionals.
Opioids like morphine can be detected via several drug tests. Standard opioid tests are done via urine, blood, hair, or saliva samples. Depending upon the needs of the test, different methods may be selected.
The drug tests below can detect morphine in the body for various timelines:
|Urine||Up to three days|
|Blood||Up to 24 hours|
|Saliva||Up to 36 hours|
|Hair||Up to 90 days|
Each of the above tests is accurate and relatively painless. None of them are associated with negative health effects, and they are all safe to do. The person or organization that requested your drug test will likely have specifications regarding the specific type of test you must take.
Tests Used to Detect Morphine
A variety of methods are used to collect samples to test for morphine. Urine, blood, hair, and saliva or sweat tests can be completed to accurately assess the presence of morphine in someone’s system.
- Urine sample: A clean urine sample is collected by filling a container approximately half full. You must begin urinating, stop, and collect the sample. Then, you may finish urinating in the toilet.
- Blood sample: Blood samples are typically drawn from the arm using a small needle. Blood is collected into a vial that is sent to a laboratory for testing.
- Saliva collection: Saliva is collected by either spitting gently into a tube or by placing a swab inside your cheek for a few minutes.
- Hair test: A small hair sample is cut from any part of the body, though typically from the head. The hair is then tested for substances.
- Sweat test: Sweat samples take longer to collect and are usually collected via a patch that is left on the skin for approximately a week.
Depending on how quickly your sample is delivered and processed in a laboratory, opioid test results are typically available within a few hours to a few days.
Morphine Half-Life & Administration Methods
The half-life of intravenously injected morphine is estimated at 2.5 to 3 hours. To control chronic pain, such as in cancer patients, morphine may then need to be administered every one to two hours for the analgesic effects to be felt continuously.
The half-life of orally ingested morphine is also estimated to be approximately two to three hours. Extended-release versions of morphine are designed to be taken every 12 to 24 hours.
It is highly recommended to begin with the lowest dose of morphine possible, no matter which administration method is being used. With repeated doses, morphine levels can accumulate in the body and cause serious health effects. The goal is to always maintain the lowest dose that provides relief, as risks increase with higher doses.
What Impacts How Long Morphine Stays in Your Body?
Many factors can impact how long morphine remains in your body. Age, fitness, health conditions, and history of substance use all affect how quickly morphine is metabolized.
Here are some of the factors that influence how long it remains in the body:[4,6-8]
- Health conditions: Conditions such as hepatic and renal impairment are known to increase the half-life of morphine, meaning it remains in the body longer than people with healthy hepatic and renal function.
- Age: Older people may hold morphine in their bodies longer than average since the liver’s ability to metabolize drugs is reduced with age, resulting in a longer half-life for the drug.
- Drug tolerance: A person’s ability to tolerate morphine, as well as how much morphine they have been taking, impacts how long it remains in their body.
- History of use: How long someone has been taking morphine can impact how quickly it is metabolized from the body. People who have been taking it for longer have larger amounts built up in their bodies.
In addition to known factors that influence how long morphine or other opioids remain in the body, there is a good amount of individual variation.
- Morphine. National Health Service UK. Published January 26, 2022. Accessed September 6, 2023.
- Side effects of morphine. National Health Service UK. Published January 26, 2022. Accessed September 6, 2023.
- Opioid Testing. Testing.com. Published September 28, 2022. Accessed September 6, 2023.
- Morphine. Hospira, Inc. Published September 2021. Accessed September 6, 2023.
- Leppert W. Pain Management in Patients with Cancer: Focus on Opioid Analgesics. Journal name. 2011; 15: 271-279. DOI: 10.1007/s11916-011-0201-7
- Le J. Drug Metabolism. Merck Manual Professional Version. Published September 2022. Accessed September 6, 2023.
- Opioid facts for teens: More FAQs about opioids. National Institute on Drug Abuse. Published July 2018. Accessed September 6, 2023.
- Mangoni AA, Jackson SH. Age-related changes in pharmacokinetics and pharmacodynamics: basic principles and practical applications. Br J Clin Pharmacol. 2004;57(1):6-14. doi:10.1046/j.1365-2125.2003.02007.x