How long does the effect of morphine last?
Nov 25, 2025
Source: Cainiu Health
Dr. Tian Hongbo
Introduction
The duration of morphine's effect varies depending on the route of administration. With conventional injectable formulations, the effect lasts 4 to 6 hours. When administered via injection (such as intravenous or intramuscular injection), the drug is rapidly absorbed, resulting in quick onset but also rapid metabolism. The analgesic effect typically lasts 4 to 6 hours, making it suitable for situations requiring rapid relief from acute severe pain. Repeated dosing at regular intervals is necessary to maintain adequate pain control.
Generally, the duration of morphine's effect varies depending on the route of administration. Conventional injections typically last 4–6 hours, while oral sustained-release formulations can extend the effect up to 12 hours. If in doubt, it is recommended to consult a healthcare professional in advance. Detailed analysis is as follows:
When administered via injection (e.g., intravenous or intramuscular), the drug is rapidly absorbed, resulting in quick onset but also rapid metabolism. The analgesic effect usually lasts 4–6 hours, making it suitable for rapidly relieving acute, severe pain. Repeated dosing at regular intervals is required to maintain pain relief.
Oral sustained-release formulations release the drug slowly, prolonging the absorption process and extending the analgesic effect to approximately 12 hours. These are suitable for long-term management of chronic pain (such as cancer-related pain), reducing the frequency of dosing and minimizing fluctuations in blood drug concentration. However, the tablets must be swallowed whole and should not be split, crushed, or chewed, as this would disrupt the sustained-release mechanism.
Morphine is a controlled substance and must be used strictly according to prescription; self-medication or dose adjustment is not permitted. During treatment, patients' respiration and level of consciousness should be closely monitored, and medical attention should be sought immediately if abnormalities such as respiratory depression occur. Long-term use may lead to dependence, and discontinuation should be done gradually under medical supervision.
