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Buprenex: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on March 7, 2022.

1. How it works

  • Buprenex is a brand (trade) name for buprenorphine injection which is an opioid medication that may be used to treat severe pain.
  • Buprenex (buprenorphine) acts on mu opioid receptors to provide pain relief. At low dosages it acts as a partial mu agonist and provides analgesic effects; however, at higher dosages buprenorphine's analgesic effects plateau and it then behaves like an antagonist. It also has weak kappa antagonist activity.
  • Buprenex 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

  • May be used for the relief of pain severe enough to require an opioid analgesic and for which alternative pain relief agents are inadequate. This pain may be associated with conditions such as cancer, kidney stones, or nerve disorders, or occur postoperatively.
  • May be given intravenously (into a vein) or intramuscularly (into a muscle).
  • Buprenex has been studied in children aged 2 years to 12 years and may be used safely.
  • Available as a generic under the name buprenorphine injection.

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:

  • Sedation has been reported in approximately two-thirds of people receiving Buprenex, and is its most common side effect. Although people were sedated, they were easily aroused to an alert state.
  • Nausea, dizziness, constipation, and vertigo have also been reported. Headache, sweating, low blood pressure, vomiting, hypoventilation, and miosis (pinpoint pupils) are less commonly reported. May cause adrenal suppression, androgen deficiency, and liver toxicity; liver function may need monitoring.
  • Buprenex carries a Black Box warning for respiratory depression (severe difficulty with breathing). This is more likely to occur in the elderly, debilitated, or those with pre-existing breathing problems, especially during the initiation of Buprenex or following a dosage increase.
  • May cause sleepiness or dizziness and affect a person's ability to drive or operate machinery. Avoid alcohol.
  • May cause a severe lowering of blood pressure, or a sudden drop in blood pressure when going from sitting to standing.
  • Buprenex is a Schedule III controlled substance and is subject to the same regulations as other Schedule III controlled substances.
  • Buprenex has a high potential for abuse, similar to other opioid analgesics. The risk may be higher in those with a personal or family history of substance or alcohol abuse or with a psychiatric disorder. Supplies of Buprenex may be sought out by drug users and misused which may lead to overdose and death.
  • There is a risk of heart rhythm disorders (such as QT prolongation) associated with Buprenex, particularly at higher dosages.
  • May not be suitable for people with preexisting significant respiratory depression, acute or severe bronchial asthma, known or suspected gastrointestinal obstruction, or hypersensitivity to buprenorphine.
  • Buprenex may be addictive and cause psychological dependence and withdrawal symptoms, particularly when used for long periods.
  • May interact with several other drugs including other opioids, benzodiazepines, and other central nervous system depressants resulting in profound sedation, respiratory depression, and sometimes death. May also interact with drugs metabolized through several CYP hepatic enzyme systems (such as CYP3A4 or CYP2D6) or drugs that also release serotonin (such as antidepressants, antipsychotics, and tramadol).
  • May not be suitable for some people, or the dosage of Buprenex may need reducing in those with liver disease, the elderly or frail, with a history of drug or alcohol abuse, with psychiatric disorders, previous head injury or raised intracranial pressure, a history of seizure disorders, with certain gastrointestinal conditions, respiratory disease, biliary tract dysfunction, or certain other concomitant conditions. Anaphylactic and allergic reactions have been reported with Buprenex.
  • Older people, over the age of 65 years, have an increased sensitivity to buprenorphine, and lower dosages should be used.
  • Prolonged use during pregnancy may cause neonatal opioid withdrawal syndrome in the newborn baby which may be life-threatening if not noted and treated. Symptoms include irritability, hyperactivity, an abnormal sleep pattern, high-pitched cry, tremor, diarrhea, or failure to put on weight. Avoid use during pregnancy unless the benefits outweigh the risks and advise the mother of the risk of neonatal withdrawal syndrome.

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

Buprenex is a potent analgesic that should be only used to treat moderate to severe pain under strict conditions when other analgesics have proved inadequate. Sedation is the main side effect and it also carries a risk for life-threatening respiratory depression, addiction, abuse, and misuse that may lead to overdose and death.

5. Tips

  • Buprenex should only be administered by a health professional and strictly as directed by your doctor.
  • If you are taking Buprenex for severe pain, tell your doctor if you begin to have breakthrough pain.
  • Tell your doctor if you experience any difficulty with breathing or shortness of breath after taking Buprenex, especially within the first 24 to 72 hours of initiating therapy.
  • Avoid sudden discontinuation of Buprenex. The dosage of Buprenex must be tapered off slowly to minimize withdrawal symptoms which include restlessness, runny nose and eyes, muscle pain, and insomnia. When the time comes to discontinue Buprenex, your doctor will advise you on a tapering schedule.
  • Rise carefully from a sitting to a standing position to minimize blood pressure lowering effects from Buprenex which may result in dizziness increasing your risk of falls.
  • Buprenex may cause constipation. Talk to your doctor about taking laxatives as a preventive against constipation if you are prescribed Buprenex.
  • Buprenex may cause androgen deficiency that may cause symptoms such as low libido, impotence, erectile dysfunction, amenorrhea, or infertility. Talk to your doctor if this happens to you.
  • Always talk to your doctor or pharmacist before buying anything over-the-counter to check if it is compatible with Buprenex. If Buprenex is administered with other drugs that also release serotonin, such as tramadol, lithium, antidepressants, a condition called serotonin syndrome may develop. Symptoms include agitation or restlessness, sweating, diarrhea, headache, confusion, rapid heart rate, high blood pressure, dilated pupils, loss of muscle coordination, twitching muscles, or muscle rigidity. See your doctor immediately.
  • If you are a woman of child-bearing age you should use adequate contraception to ensure you do not become pregnant while taking Buprenex. If you inadvertently become pregnant, tell your doctor straight away as there is a risk your baby may be born with neonatal withdrawal syndrome which will need to be treated. Do not breastfeed while taking Buprenex.
  • Do not drive or operate machinery if you are prescribed Buprenex because it may impair your ability to perform these tasks unless you are tolerant to its effects.
  • You should not drink alcohol while you are prescribed Buprenex because it may impair your ability to concentrate and also increase the risk of side effects such as respiratory depression.

6. Response and effectiveness

  • The analgesic effect after IV administration usually occurs within 10-30 minutes; peak analgesic effects occur within 60 minutes. The analgesic effect of buprenorphine usually lasts for an average of six hours but the duration may vary between individuals.
  • Buprenex has a very slow rate of dissociation from its receptors. This may account for its long duration of effect compared with morphine, its unpredictable reversal with opioid antagonists, and its low rate of physical dependence.

7. Interactions

Medicines that interact with Buprenex may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with Buprenex. 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 Buprenex include:

  • anticholinergic drugs, such as benztropine
  • antidepressants, such as tricyclic antidepressants (eg, amitriptyline), monoamine oxidase inhibitors (eg, isocarboxazid, phenelzine, and tranylcypromine), or SSRIs (eg, fluoxetine, sertraline)
  • antipsychotics (such as butyrophenones, phenothiazines, or thioxanthenes) and atypical antipsychotics (eg, olanzapine, quetiapine, ziprasidone)
  • any medication that inhibits or induces CYP3A4. Inhibitors include erythromycin, ketoconazole, and ritonavir. Inducers include rifampin, carbamazepine, or phenytoin.
  • any medication that may cause drowsiness, such as amphetamines, first-generation antihistamines (such as doxylamine or promethazine), metoclopramide, or opioids (such as codeine, methadone, or morphine)
  • benzodiazepines (eg, diazepam, lorazepam) or other central nervous system depressants, such as barbituates or sedatives
  • diuretics, such as bendofluazide or furosemide
  • HIV medications such as atazanavir, efavirenz, nevirapine, or ritonavir
  • mixed agonists/antagonists and partial agonist opioids, such as butorphanol, nalbuphine, or pentazocine
  • muscle relaxants, such as methocarbamol, cyclobenzaprine, carisoprodol, metaxalone, tizanidine, or baclofen.
  • naloxone and naltrexone
  • QT-prolonging medications such as amiodarone and flecainide
  • rifampin
  • St. John's Wort.

Any medication that releases serotonin (such as amitriptyline, tramadol, or St. John's Wort) may interact with Buprenex and cause serotonin syndrome, a potentially fatal condition that occurs when levels of serotonin get too high in your body. Symptoms can range from mild (shivering and diarrhea) to severe (muscle rigidity, fever, and seizures).

Avoid drinking alcohol or taking illegal or recreational drugs while taking Buprenex.

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


Buprenex injection (buprenorphine hydrochloride) Updated 09/2021. Indivior Inc.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Buprenex 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: March 6, 2022.