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Hydromorphone: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on July 16, 2021.

1. How it works

  • Hydromorphone is a derivative of morphine and is used to relieve pain. Hydromorphone binds to mu opioid receptors in the brain and stomach and has strong pain-relieving effects.
  • Hydromorphone is a full agonist at the mu receptor (full agonists have a larger effect at higher dosages).
  • Hydromorphone belongs to the class of medicines known as narcotic analgesics. It may also be called an opioid analgesic. An analgesic is a drug that is used to relieve pain.

2. Upsides

  • Relieves moderate-to-severe acute and chronic pain not controlled by other non-narcotic pain-relieving medicines.
  • Approximately 5 times more potent than morphine on a weight-for-weight basis; however, conversion charts vary in their estimates of equianalgesic dosages, so caution should always be used when changing from one narcotic to another.
  • Hydromorphone will help calm a cough, although other, less potentially addictive cough suppressants may be preferred.
  • Generic hydromorphone is available.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Light-headedness, nausea, vomiting, constipation, dizziness, low blood pressure, flushing, itching, red eyes, and headache.
  • May also cause drowsiness and affect a person's ability to drive or operate machinery. Has a higher potential to cause sedation than morphine.
  • There is a risk of respiratory depression (unusually slow or shallow breathing) when taking hydromorphone. The risk is higher in the elderly, debilitated, or in those with pre-existing breathing problems, even at dosages usually recommended.
  • May also cause the pupils of the eye to constrict (pinpoint pupils). Pinpoint pupils are a common sign of overdose but are not a definite sign.
  • Avoid alcohol at all times (alcohol can increase side effects and also blood levels of the drug leading to a fatal overdosage).
  • Hydromorphone can be habit-forming (addictive), even at regular doses. It has a high abuse potential, and personal legitimate supplies of hydromorphone may be sought out by drug seekers. Babies born to mothers who are physically dependent on hydromorphone will be born physically dependent on hydromorphone themselves.
  • Tolerance may develop to hydromorphone's effect. This means that increasing dosages are needed to maintain the same level of pain relief with time.
  • Should be used short-term only. When given long term, may cause withdrawal symptoms if abruptly stopped. Taper dosage off slowly under a doctor's supervision.
  • Lower dosages of hydromorphone are needed in people with moderate liver or kidney disease. Initiate treatment with one-fourth to one-half of the usual hydromorphone starting dose.
  • May not be suitable for some people including those any type of pre-existing breathing problems, with severe liver or kidney disease, with head injuries, with certain gastrointestinal conditions, at risk for low blood pressure, with prostatic hypertrophy, with psychiatric conditions, a history of seizures, drug or alcohol dependency. May cause an allergic reaction in people allergic to sulfites because the tablets contain sodium metabisulfite.
  • May interact with several other drugs including those that also cause sedation or respiratory depression or which are metabolized by similar hepatic enzymes.
  • Hydromorphone is classed as a schedule II controlled drug, because of its high potential for abuse and risk of respiratory depression.
  • Prolonged use during pregnancy can result in neonatal withdrawal syndrome, which may be life-threatening if not recognized early. Use during pregnancy and while breastfeeding is not recommended.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Hydromorphone is a morphine-like pain-relieving medicine that may be given to relieve severe pain that is not relieved by other pain-relieving treatments. It carries a high risk of respiratory depression (unusually slow or shallow breathing) and is potentially addictive. It should be used at the lowest dosage for the shortest possible time, and reduced dosages should be given to those with liver or kidney disease.

5. Tips

  • Take exactly as directed and never take more than your doctor has directed. Low dosages are used initially to reduce the risk of side effects. Use for the shortest time possible.
  • Hydromorphone may make you sleepy and impair your reaction time. Do not drive or operate machinery if hydromorphone affects you in this way.
  • Do not drink alcohol while taking hydromorphone. It can increase the risk of side effects such as sedation and respiratory depression and increase blood levels of hydromorphone to potentially fatal levels.
  • Do not crush, chew, or attempt to dissolve slow-release forms of hydromorphone. This may result in a potentially fatal overdose.
  • Do not take any other medications with hydromorphone, unless they have been prescribed by your doctor. This includes medicines bought over the counter and herbal supplements.
  • May cause a rapid lowering of blood pressure when going from a sitting to a standing position. This may make you feel faint and increase your risk of falling. Always stand up slowly.
  • Keep well out of reach of children and pets. Even just one accidental dose can be fatal.
  • If you have been taking hydromorphone for more than a few days, do not stop it abruptly. Talk to your doctor about tapering off the dosage.
  • Tell your doctor if you are pregnant or breastfeeding before taking hydromorphone because it may not be suitable for you.

6. Response and effectiveness

  • Hydromorphone is active once absorbed and reaches peak concentrations within 45 minutes.
  • Liver disease can increase concentrations of hydromorphone up to four-fold. Kidney disease can increase the time it takes for hydromorphone to be eliminated from the body up to three-fold.
  • Hydromorphone has a shorter half-life than morphine and a greater risk of sedation.

7. Interactions

Medicines that interact with hydromorphone may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with hydromorphone. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with hydromorphone include:

  • anticonvulsants, such as carbamazepine, phenytoin, phenobarbital, or primidone
  • antidepressants, such as tricyclic antidepressants (eg, amitriptyline), monoamine oxidase inhibitors (eg, isocarboxazid, phenelzine, and tranylcypromine), or SSRIs (eg, fluoxetine, sertraline)
  • anticholinergics, such as benztropine (may increase the risk of urinary retention or severe constipation)
  • antipsychotics (such as butyrophenones, phenothiazines, or thioxanthenes) and atypical antipsychotics (eg, olanzapine, quetiapine, ziprasidone)
  • any medication that may cause drowsiness, such as amphetamines, benzodiazepines (eg, diazepam, lorazepam), first-generation antihistamines (such as doxylamine or promethazine), metoclopramide, or opioids (such as codeine, morphine)
  • buprenorphine
  • diuretics, such as furosemide or HCTZ (may reduce their effectiveness)
  • ipratropium
  • isocarboxazid
  • muscle relaxants, such as cyclobenzaprine
  • pentazocine
  • selegiline.

Avoid drinking alcohol or taking illegal or recreational drugs while taking hydromorphone. Use of hydromorphone with alcohol, benzodiazepines, or other CNS depressants may result in profound sedation, respiratory depression, coma, and death.

Note that this list is not all-inclusive and includes only common medications that may interact with hydromorphone. You should refer to the prescribing information for hydromorphone for a complete list of interactions.


Hydromorphone. Revised 12/2019.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use hydromorphone only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2022 Revision date: July 18, 2021.