A strong opioid painkiller for severe pain
Hydromorphone
A strong opioid painkiller used for severe pain, including cancer pain, available in standard and slow-release forms.
What is Hydromorphone?
Hydromorphone is a strong opioid painkiller used for severe pain, including cancer pain. It comes in quick-acting and slow-release (modified-release) forms taken by mouth. Like all strong opioids, its dominant risks are slowed or dangerous breathing (respiratory depression), the potential for dependence, drowsiness and constipation. It is a controlled drug and is very potent, so careful dosing is essential and it should never be swapped dose-for-dose with other opioids without specialist calculation. It is used at the lowest effective dose and reduced gradually when stopping.
Education and reference only. This is a plain-language guide to Hydromorphone — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Hydromorphone is a strong opioid painkiller used to treat severe pain, often including pain related to cancer or other serious illness. It is available as quick-acting forms for pain that comes and goes, and as slow-release (modified-release) forms that give steady relief over the day. As a strong opioid it is a controlled drug, with its supply tightly regulated. A key point is that it is very potent, so the amounts used are small and doses must be worked out carefully, especially when switching from another opioid. It is prescribed and supervised by healthcare professionals.
How it works
Hydromorphone works on opioid receptors in the brain and spinal cord, the body's own pain-control system, changing how pain signals are processed so that severe pain feels less intense. The slow-release forms release the medicine gradually to give steady background pain control, while quick-acting forms work faster for breakthrough pain. The same actions in the brain that relieve pain also slow the drive to breathe, cause drowsiness, and can produce a sense of calm or pleasure, which is why respiratory depression, sedation and dependence are the main concerns and why its potency demands careful dosing.
Company & origin
Originated / developed by: Generic.
A strong opioid painkiller used in the UK for severe pain, including cancer pain; a controlled drug that is very potent.
Practical use
How to take Hydromorphone
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it exactly as prescribed; swallow slow-release tablets or capsules whole and do not crush or chew them.
- Do not drink alcohol or take other sedating medicines with it, as this can dangerously slow your breathing.
- Expect constipation and ask about a regular laxative; do not drive if you feel drowsy.
- Never switch from another opioid without your team calculating the dose, as hydromorphone is very potent.
- Do not stop suddenly after regular use; ask your prescriber how to reduce it gradually to avoid withdrawal.
Weighing it up
Advantages & disadvantages of Hydromorphone
Advantages
- A strong, effective painkiller for severe pain, including cancer pain.
- Available in both quick-acting and slow-release forms to suit different patterns of pain.
- An option for people who do not get on with, or cannot use, other strong opioids.
Disadvantages
- Can cause slowed, dangerous breathing, especially with alcohol or other sedatives.
- Carries a risk of dependence and is a controlled drug.
- Very potent, so dosing must be precise and it commonly causes drowsiness and constipation.
Practical use
Good to know
The dominant safety points with hydromorphone are those of any strong opioid, made more important by how potent it is. The most dangerous risk is respiratory depression, where breathing slows and becomes shallow; this is more likely at higher doses, in frail or older people, and especially when combined with alcohol, sleeping tablets or other sedating medicines. Because it is very potent, doses are small and must never be swapped dose-for-dose with other opioids such as morphine without a careful specialist calculation, as errors can be dangerous. Dependence can develop with regular use, so it is used at the lowest effective dose and reduced gradually when stopping to avoid withdrawal. Constipation is very common and usually needs a regular laxative, and drowsiness can affect driving. Slow-release tablets must be swallowed whole, not crushed.
Who should not take it / use with caution
- People with serious breathing problems or respiratory depression should not take it.
- People who have had a serious allergic reaction to it should not take it.
- It is used with great care, or avoided, alongside alcohol, sleeping tablets and other sedating medicines.
- It is used cautiously, often at lower doses, in older or frail people and those with liver or kidney problems.
Monitoring
- Reviewing how well pain is controlled and whether the dose or form needs changing.
- Watching for drowsiness, slowed breathing and signs of dependence.
- Checking for constipation and reviewing kidney and liver function where relevant.
Side effects
- Drowsiness, dizziness and feeling sick, often easing after the first days.
- Constipation, which is very common and usually needs a laxative.
- Slowed breathing, which is the most serious risk, especially with sedatives or high doses.
- With regular use, dependence and withdrawal if stopped suddenly.
Key interactions
- Alcohol, sleeping tablets, benzodiazepines and other sedatives add to the risk of dangerously slowed breathing.
- Other opioids add to the effect and risk, and switching between them needs careful dose calculation.
- Some medicines change how the body handles hydromorphone, so tell your prescriber everything you take.
Available as: Quick-acting and slow-release capsules and tablets taken by mouth, and a form for injection.
Answers
Hydromorphone: frequently asked questions
What is hydromorphone used for?
It is a strong opioid painkiller used for severe pain, including cancer pain, in both quick-acting and slow-release forms.
What is the most serious risk?
Slowed, shallow breathing (respiratory depression), which is more likely at higher doses and with alcohol or other sedating medicines.
Why does its potency matter?
Hydromorphone is very potent, so doses are small and it must never be swapped dose-for-dose with other opioids without a careful specialist calculation.
Will it make me constipated?
Yes, constipation is very common with strong opioids and usually needs a regular laxative, so ask your team about this.
Can I stop it suddenly?
No. After regular use, stopping suddenly can cause withdrawal, so it should be reduced gradually under your prescriber's guidance.
The wider class
About Strong opioid painkiller
Hydromorphone belongs to the strong opioid painkiller class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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