Tramadol
A synthetic opioid that also weakly blocks serotonin and norepinephrine reuptake, used for moderate to severe pain.
Drug card
- Class
- Opioid
- How it works
- Activating mu-opioid receptors in the brain and spinal cord to dull pain
- Used for
- Moderate to severe pain, such as after surgery or injury
- Long-lasting pain when weaker painkillers fail
- Known for
- Seizures, even within the usual dose range
- Serotonin syndrome with serotonergic drugs
- Its name
- -adol means an opioid analgesic (tramadol type)
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does tramadol work?
Tramadol is a weak mu agonist; its metabolite O-desmethyltramadol (M1), made by CYP2D6, binds mu receptors far more strongly. It also weakly blocks the reuptake of norepinephrine and serotonin, which adds to its pain relief, so naloxone only partly reverses its effect.
Like other opioid analgesics: Opioids activate mu-opioid receptors, the G protein-coupled receptors used by the body's own opioids in the brain, spinal cord and gut. In nerve cells this opens potassium channels and closes calcium channels, so neurons fire less and release less pain transmitter such as substance P. They also depress the brainstem breathing center, narrow the pupils and slow the gut; tolerance and dependence build with regular use.
Uses
What is tramadol used for?
- Moderate to severe pain, such as after surgery or injury
- Long-lasting pain when weaker painkillers fail
Side effects
Side effects of tramadol
- Seizures, even within the usual dose rangeKnown forSerious
- Serotonin syndrome with serotonergic drugsKnown forSerious
- Nausea and vomiting
- Dizziness
- Constipation
- Headache
- Drowsiness
- Dry mouth
- Slowed breathing (respiratory depression)Serious
- Low sodium (hyponatremia)Serious
- Low blood sugar (hypoglycemia)Serious
- Addiction, misuse and dependenceSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Seizure risk rises in epilepsy and with SSRIs, SNRIs, tricyclics, MAOIs, antipsychotics or other opioids.
- Contraindicated with MAOIs or within 14 days of one; with other serotonergic drugs watch for serotonin syndrome.
- Contraindicated under 12 years, and under 18 after tonsil or adenoid removal: ultra-rapid CYP2D6 metabolizers make too much M1.
Good to know: Its dual action sets it apart from other opioids, and unlike morphine it has not been shown to release histamine.
Remember it
A way to remember it
MORPHINE
- M
- Miosis (pinpoint pupils)
- O
- Opioid withdrawal if stopped suddenly
- R
- Respiratory depression
- P
- Pruritus (itching)
- H
- Hypotension
- I
- Intestinal slowing: constipation
- N
- Nausea and vomiting
- E
- Euphoria, then dependence and addiction
Written for biofideX
Its name
-adol means opioid analgesic (tramadol type)
Tramadol and tapentadol relieve pain through mu-opioid receptors and by blocking norepinephrine reuptake. Nadolol, a beta blocker, ends in -adol by chance.
- Every drug name stem
Its class
Opioid analgesics
Easily mixed up with opioid antagonists, benzodiazepines and antimotility drugs.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Tramadol hydrochloride extended-release tablets: label (DailyMed)
- Tramadol (NCI Thesaurus)
- Tramadol (NHS)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Pain, fever and inflammation
Tramadol is one of 15 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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