Fentanyl: What It’s For, Dosing, How to Take & Side Effects

Fentanyl is a synthetic opioid medication that works similarly to morphine, but is 10 to 50 times more potent. It is usually prescribed to relieve chronic pain or intense pain, or it can be used to complement general or local anesthesia. 

This medication can be found as a transdermic patch that is applied directly to the skin. It can be obtained at a pharmacy with a prescription from the doctor. 

Fentanyl is also available as an injectable solution for use in the hospital setting. It is administered by the nurse intramuscularly as an injection or through an IV infusion. It can also be injected intervertebrally by a doctor. 

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What is fentanyl prescribed for?

Fentanyl is commonly used for: 

  • The treatment of chronic pain or intense pain that is unable to be managed with combinations of acetaminophen and opioids, NSAIDs or short-acting opioids 
  • Pre-operative analgesia
  • To induce and/or maintain general anesthesia and epidurals
  • To complement local anesthesia 
  • To control post-operative pain

Fentanyl can be prescribed as a transdermic patch to be used in out-patient settings, or administered though IV or IM injection in a hospital-setting.

Dosing and how to take

Dosing for fentanyl depends on the form prescribed: 

1. Fentanyl transdermic patch

There are many doses of fentanyl patches available for use at home. Patches can be designed to release 12, 25, 50 or 100 mcg per hour over 72 hours. The dose prescribed depends on pain intensity, the person’s general health status, and other medications the patient is already taking. It can be used by adults or children over 2 as prescribed by the doctor. 

To apply a patch, pick an area of the body with clean, dry and intact skin with no hair. Many patients apply it to the upper trunk, on the arm, or on the back. Patches should be applied to the upper back in children so that they cannot be removed. Once applied, it can come in contact with water. 

If the patch peels off before 3 days, you should throw this one away and apply a new patch to a different area of the body. Be sure to inform your doctor. After 3 days, you can remove the patch and discard it safely by folding it twice with the sticky part covered. You should also take note of the date it was applied on the bottom of the patch’s package. 

2. Injectable fentanyl

Injectable fentanyl can be administered into a muscle or vein by a health care professional. It can also be administered by a doctor as an epidural, which means it is injected in the spaces between vertebrae. 

Some factor that should be considered in determining the right dose include the patient‘s age, weight, activity level and health status, as well as, if applicable, other medications already being taken, the type of anesthesia being used and the surgery being performed.

Side effects

The most common side effects from fentanyl use in adults include insomnia, drowsiness, dizziness, nausea, vomiting or headache. In children, the most common side effects include headache, vomiting, nausea, constipation, diarrhea or generalized itching. 

With fentanyl injectables, the most common side effects that can occur during treatment are nausea, vomiting or muscle rigidity.

Using higher doses than prescribed can also lead to an overdose, which usually presents with symptoms like:

  • Difficulty breathing
  • Slow or superficial breathing
  • Cold or moist skin
  • Pale, blue or grey skin, purple
  • Purple lips and nails
  • Small pupils
  • Loss of consciousness
  • Lack of responsiveness
  • Vomiting
  • Respiratory arrest 

In these cases, patients should be taken to a hospital immediately or call an ambulance, as overdoses are life-threatening and require immediate care. 

Can fentanyl be addicting?

Regular use of fentanyl in doses higher than what is prescribed can be addicting. This substance is more potent than morphine, meaning just a small amount can guarantee a powerful effect. Dopamine is the neurotransmitter that is released with opioid use, and if this medication is used regularly, dopamine receptors will usually start to tolerate the dose. This can lead to increased doses being needed over time to reach the same effect, leading to addiction. 

Contraindications for use

Fentanyl should not be used by children under 2 or by people with an allergy to fentanyl or any of its components. This medication should not be used by anyone with an allergy to other opioid medications. 

In addition, this medication should not be used by pregnant women, breastfeeding women, or during labor, unless prescribed by a doctor.