Fentanyl vs. Morphine: What’s the Difference?

Fentanyl and morphine are opioid painkillers. Both are used for painful conditions that don’t respond to over-the-counter medications like aspirin or acetaminophen. But fentanyl is 50 to 100 times more potent than morphine.[1] It’s a much more dangerous and addictive option. 

Understanding Fentanyl & Morphine 

Morphine and fentanyl are powerful prescription opioids used for pain relief.

Morphine treats pain triggered by traumatic injury, surgery and cancer.[2] It is a naturally occurring opioid derived from the opium poppy plant. 

Morphine can be administered through oral tablets, liquids and injections (intravenously/intramuscularly). It is often thought of as the “baseline” opioid in medicine.

Fentanyl is a synthetic-opioid compound that is much more potent than morphine.[3] It is sometimes used for patients struggling with excruciating pain that can’t be properly treated with less powerful painkillers. In most cases, fentanyl is administered in hospital settings. 

Doctors can deliver fentanyl via skin patches, orally dissolving tablets (lozenges) and intravenous injections. While it’s helpful for some people, misuse is both common and extremely dangerous. 

Dealers lace street drugs with fentanyl, as it’s both powerful and easy to make.[3] Contamination is a major contributor to fatal opioid overdoses in the United States.

How Do These Medications Work? 

Opioids bind to dedicated receptors within the brain, spinal cord and other organs. When they’re attached, opioids block pain signals. They also release a neurotransmitter called dopamine.[4]

Dopamine is a powerful chemical associated with feelings of pleasure, release and reward. The brain remembers the feeling that accompanies these massive increases in dopamine, and it can be difficult to ignore the sensation. Many people keep taking these drugs to recreate the experience. 

Fentanyl & Morphine: Comparison 

Morphine and fentanyl both belong to the family of opioids, but they are distinct from each other due to their chemical makeup and power. This table can help you understand what sets these two medications apart:

Fentanyl & Morphine Side Effects 

Powerful opioids like morphine and fentanyl cause both physical and mental side effects. They can be split into short-term and long-term problems. 

Know that some side effects, including life-threatening versions, can take hold when using these drugs even once. 

Short-Term Effects 

Opioids cause immediate chemical changes within the brain. You may experience euphoria followed by significant drowsiness. At high doses, which can take hold with even tiny amounts of fentanyl, significant respiratory depression appears. These episodes can be life-threatening, as brain cells are starved of oxygen. 

Long-Term Effects 

People who misuse opioids for long periods can develop severe gastrointestinal problems, including persistent constipation. When people try to quit using opioids, they may experience significant symptoms like nausea, diarrhea and overwhelming drug cravings. 

People who misuse opioids with a needle can develop infections, including some that travel to the heart and cause cardiac problems. People may also experience blood-borne infections like HIV and hepatitis. 

Addiction Potential: Is One More Addictive Than the Other?

Because both drugs have a high potential for addiction, fentanyl and morphine should not be taken casually or without appropriate medical supervision.[6] They have unique addiction risks. 

Fentanyl is a stronger drug. It causes bigger reactions within the brain, which is typically associated with a higher addiction risk. However, fentanyl is so strong that it can cause an overdose the first time it is used. Some people don’t survive their first experience with fentanyl. 

Morphine is weaker than fentanyl, and that comes with addiction risks. People can take low doses for longer periods without enduring severe drug overdoses. Their repeated use can lead to severe brain changes that lead to addiction. This drug’s weakness can increase your long-term addiction risks. 

Key Differences Between Fentanyl & Morphine

While fentanyl and morphine are very similar, important differences exist. They include the following:

• Fentanyl is a synthetic (man-made) drug. Morphine originates from the sap of the poppy plant. 
• Fentanyl is used in hospital settings for severe pain. Morphine can be used for moderate pain stemming from accidents, surgeries and illness. 
• The primary difference between these two lies in their strength. Fentanyl is as much as 100 times more potent than morphine.