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Naloxone 400 micrograms/ml solution for injection – patient leaflet, side effects, dosage

Last updated: · Text from the MHRA, as of · About this document

Medicine status: Prescription only (POM) Details

Medicine strength:
400 micrograms/ml
Contains active substance:
ATC code:

Patient leaflet - Naloxone 400 micrograms/ml solution for injection

1. What Naloxone 400 micrograms/ml solution for injection/infusion is and what it is used for

Naloxone 400 micrograms/ml solution for injection/infusion is a drug used to counter the effects of opioid overdose, for example morphine overdose. Naloxone 400 micrograms/ml solution for injection/infusion is used for reversal of unwanted effects of opioids for countering life-threatening depression of the central nervous system and respiratory system (breathing difficulties).

Naloxone 400 micrograms/ml solution for injection/infusion is also used to diagnose an acute opioid overdose or intoxication.

If a woman was given analgetic drugs during labour, a newborn child can be treated with Naloxone 400 micrograms/ml solution for injection/infusion for reversal of unwanted effects of opioids, e.g. if he/she suffers from breathing problems or depression of central nervous system.

2. What you need to know before Naloxone

400 micrograms/ml solution for injection/infusion is administered to you

Naloxone 400 micrograms/ml solution for injection/infusion must not be administered

  • If you are allergic (hypersensitive) to naloxone hydrochloride or to any of the ingredients of this medicine (listed in section 6).

Warnings and precautions

Talk to your doctor or pharmacist before Naloxone 400 micrograms/ml solution for injection/infusion is administered to you.

Special care will be taken

  • If you are physically dependent to opioids (for example morphine) or have received high doses of these drugs (you may get strong withdrawal symptoms after receiving Naloxone 400 micrograms/ml solution for injection/infusion because of a too rapid reversal of the opioid effect; these symptoms may be high blood pressure, palpitations, severe difficulties in breathing or cardiac arrest).
  • If you have any heart or circulation problems (because side effects like high or low blood pressure, palpitations or severe difficulties in breathing may appear more likely).

Other medicines and Naloxone 400 micrograms/ml solution for injection/infusion

Tell your doctor or pharmacist if you are taking or have recently taken any other medicines.

  • If you are taking painkilling medication like buprenorphine. The painkilling effect may even become stronger while you are treated with Naloxone 400 micrograms/ml solution for injection/infusion. However, the reversal of unwanted effects, like respiratory depression caused by buprenorphine is limited.
  • If you are taking sedatives, as Naloxone 400 micrograms/ml solution for injection/infusion may possibly have a less rapid effect.
  • If you are taking any medication that may affect your heart or circulation (e.g. antihypertensive drugs e.g. clonidine), even those not prescribed.

Naloxone 400 micrograms/ml solution for injection/infusion with alcohol

Please inform your doctor if you drank alcohol. In patients with multi-intoxication (with opioids and sedatives or alcohol) Naloxone 400 micrograms/ml solution for injection/infusion may have a less rapid effect.

Pregnancy and breast-feeding

If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.

Pregnancy

There is no adequate information available regarding the use of Naloxone 400 micrograms/ml solution for injection/infusion in pregnant women. During pregnancy, your doctor will outweigh the benefit of Naloxone 400 micrograms/ml solution for injection/infusion against possible risks to the unborn baby. Naloxone 400 micrograms/ml solution for injection/ infusion can cause withdrawal symptoms in the newborn baby.

Breastfeeding

It is not known whether Naloxone 400 micrograms/ml solution for injection/ infusion passes into breast milk and it has not been established whether infants who are breast-fed are affected by Naloxone 400 micrograms/ml solution for injection/infusion. Therefore, breast-feeding is not recommended for 24 hours after treatment

Driving and using machines

After receiving Naloxone 400 micrograms/ml solution for injection/infusion for the reversal of the effects of opioids you must not take part in road traffic, operate machinery or engage in any other physically or mentally demanding activity for at least 24 hours since the effects of opioids may possibly recur.

PACKAGE LEAFLET: INFORMATION FOR THE PATIENT

Naloxone

400 micrograms/ml solution for injection/infusion naloxone hydrochoride

Naloxone 400 micrograms/ml solution for injection/infusion contains sodium

This medicinal product contains 3.8 mmol (88.5 mg) sodium per maximum daily dose. Please tell your doctor, if you are on low sodium diet, he/she will take it into account.

3. How Naloxone 400 micrograms/ml solution for injection/infusion is administered

Reversal of the unwanted effects of opioids

Adults: 0.1 – 0.2 mg, if necessary additional injections of 0.1 mg may be given

Children: 0.01 – 0.02 mg per kg body weight, if necessary additional injections of the same dose may be given

Diagnosis of opioid overdose or intoxication

Adults: 0.4 – 2 mg, if necessary the injections can be repeated at intervals of 2 – 3 minutes. The maximum dose of 10 mg should not be exceeded.

Children: 0.01 mg per kg body weight, if necessary an additional injection of 0.1 mg per kg may be given

Reversal of the unwanted effects of opioids in neonates whose mothers have received opioids

0.01 mg per kg body weight, if necessary additional injections may be given For reversal of the unwanted effects of opioids (in adults, children and also in neonates) patients are monitored to ensure that the desired effect of Naloxone 400 micrograms/ml solution for injection/infusion occurs. Additional doses may be given every 1 – 2 hours if necessary. In elderly patients with heart or circulation problems or in those receiving medicines that can produce heart or circulation disorders (e.g. cocaine, methamphetamine, cyclic antidepressants, calcium channel blockers, beta-blockers, digoxin) Naloxone 400 micrograms/ml solution for injection/ infusion will be used with caution since serious side effects such as fast heart beat (ventricular tachycardia) and fibrillation have occurred. If you have the impression that the effect of Naloxone 400 micrograms/ml solution for injection/infusion is too strong or too weak, talk to your doctor.

Method of administration

Naloxone 400 micrograms/ml solution for injection/infusion will be given to you always by intravenous or intramuscular injection (into a vein or into a muscle) or, after dilution, as intravenous infusion (over a longer period). Naloxone 400 micrograms/ml solution for injection/infusion will be given by your anaesthetist or experienced physician.

If you have any further questions on the use of this product, ask your doctor or pharmacist.

4. Possible side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them.

It may be difficult to know what side effects Naloxone 400 micrograms/ml solution for injection/infusion has, because it is always given after other drugs have also been used.

The following side effects may be serious. If any of the following side effects occur, consult a doctor immediately:

Common (may affect up to 1 in 10 people):

  • Fast heart beat

Uncommon (may affect up to 1 in 100 people):

  • Changes in the way your heart beats, slow heart rate

Rare (may affect up to 1 in 1,000 people):

  • Seizures

Very rare (may affect up to 1 in 10,000 people):

  • Allergic reactions (nettle rash, nasal catarrh or a cold, difficult breathing, Quincke’s oedema (giant swelling)), allergic shock
  • Fibrillation, cardiac arrest
  • Fluids on the lungs (pulmonary oedema)

Other side effects include:

Very common (may affect more than 1 in 10 people):

  • Nausea

    B. Braun Melsungen AG

    34209 Melsungen

    Germany

    B|BRAUN

    806/12621911/0724 PACKAGE LEAFLET:

    INFORMATION FOR THE PATIENT

    Dimension = 210 x 447 mm

    2 Pages LLD-Spec.: L04

    Lätus

    2289

    GB___806

    806/12621911/0724 L04

    LF (GA)

    Production site: Jaen

    G 221363

    2289

    2289

    2289 2289 Naloxone 400 micrograms/ml solution for injection/infusion

naloxone hydrochoride

Read all of this leaflet carefully before this medicine is administered to you because it contains important information for you.

  • Keep this leaflet. You may need to read it again.
  • If you have any further questions, ask your doctor or pharmacist.
  • This medicine has been prescribed for you only. Do not pass it on to others. It may harm them, even if their signs of illness are the same as yours.
  • If you get any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet.

Common (may affect up to 1 in 10 people):

  • Dizziness, headache
  • Increased or decreased blood pressure (you may have a headache or feel

    faint)

  • Vomiting
  • If a too large dose is given after an operation, you may become excited and

    feel pain (because the painkilling effects of the medicines you were given

    will have been counteracted as well as the effects on your breathing).

Uncommon (may affect up to 1 in 100 people)

  • Involuntary trembling or quivering (tremor), sweating
  • Diarrhoea, dry mouth
  • Over breathing (hyperventilation)
  • Irritation of vessel wall has been reported after i.v. administration; local

    irritation and inflammation have been reported after i.m. administration.

Rare (may affect up to 1 in 1,000 people):

  • Tension

Very rare (may affect up to 1 in 10,000 people):

  • Discoloration and lesions of the skin (erythema multiforme)

Reporting of side effects

If you get any side effects, talk to your doctor, pharmacist or nurse. This

includes any possible side effects not listed in the package leaflet. You

can also report side effects directly via the Yellow Card Scheme Website:

www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google

Play or Apple App Store.

By reporting side effects you can help provide more information on the safety

of this medicine.

5. How to store Naloxone 400 micrograms/ml solution for injection/infusion

Keep this medicine out of the sight and reach of children.

This medicine must not be administered after the expiry date, which is

stated on the ampoule label and the carton. The expiry date refers to the

last day of that month.

Keep the ampoules in the outer carton in order to protect from light.

Store below 25°C.

Store diluted solutions below 25°C.

Do not throw away any medicines via wastewater or household waste. Ask

your pharmacist how to throw away medicines you no longer use. These

measures will help protect the environment.

6. Contents of the pack and other information

What Naloxone 400 micrograms/ml solution for injection/ infusion contains

The active substance is naloxone hydrochloride.

Each ampoule with 1 ml contains 0.4 mg naloxone hydrochloride (as

naloxone hydrochloride dihydrate).

The other ingredients are sodium chloride, hydrochloric acid diluted (for pH

adjustment) and water for injections.

What Naloxone 400 micrograms/ml solution for injection/ infusion looks like and contents of the pack

Naloxone 400 micrograms/ml solution for injection/infusion is a clear and

colourless solution in colourless glass ampoules containing 1 ml solution for

injection/infusion.

Pack sizes: 5 and 10 ampoules

Not all pack sizes may be marketed.

Marketing Authorisation Holder and Manufacturer

Marketing authorisation holder:

B. Braun Melsungen AG

Carl-Braun-Straße 1, 34212 Melsungen, Germany

Postal address:

34209 Melsungen, Germany

Manufacturer:

hameln pharmaceuticals gmbh

Langes Feld 13, 31789 Hameln, Germany

and

B. Braun Medical S.A.

Carretera de Terrassa, 121

08191 Rubí (Barcelona), Spain

This medicinal product is authorised in the Member States of the European Econimic Area and in the United Kingdom (GB and NI) under the following names:

Austria Naloxon B. Braun 0,4 mg/ml Injektions-/Infusionslösung Belgium Naloxon B. Braun 0,4 mg/ml oplossing voor injectie/ infusie

Denmark Naloxon B. Braun injektions-/infusionsvæske, opløsning Finland Naloxon B. Braun 0,4 mg/ml injektio-/infuusioneste, liuos

Germany Naloxon B. Braun 0,4 mg/ml Injektions-/Infusionslösung Greece Naloxon B. Braun 0,4 mg/ml ενέσιμο διάλυμα/διάλυμα

για έγχυση

Iceland Naloxon B. Braun 0,4 mg/ml stungulyf/innrennslislyf, lausn

Italy Naloxone B. Braun 0,4 mg/ml soluzione iniettabile/per infusione

Luxembourg Naloxon B. Braun 0,4 mg/ml Injektions-/Infusionslösung Norway Naloxon B. Braun 0,4 mg/ml injeksjons-/infusjonsvæske, oppløsning

Portugal Naloxona B. Braun 0,4 mg/ml solução injetável/para perfusão

Spain Naloxona B. Braun 0,4 mg/ml solución para inyección/ perfusión

Sweden Naloxon B. Braun 0,4 mg/ml injektions-/infusionsvätska, lösning

The Netherlands Naloxon HCl B. Braun 0,4 mg/ml, oplossing voor injectie/infusie United

Kingdom

(GB and NI)

Naloxone 400 micrograms/ml solution for injection/ infusion

This leaflet was last revised in 07/2024.

The following information is intended for healthcare professionals only:

Shelf-life after first opening:

After first opening the medicinal product should be used immediately.

Shelf-life after dilution

Chemical and physical in-use stability has been demonstrated for 24 hours below 25°C. From the microbiological point of view, the dilutions should be used immediately. If not used immediately, in-use storage times and conditions prior to use are the responsibility of the user and would normally not be longer than 24 hours at 2 to 8 °C, unless dilution has taken place in controlled and validated aseptic conditions.

For i.v. infusion Naloxone 400 micrograms/ml solution for injection/infusion is diluted only with sodium chloride 0.9 % or glucose 5 %. 5 ampoules of Naloxone 400 micrograms/ml solution for injection/infusion (2 mg) per 500 ml give 4 µg/ml. It is recommended that infusions of Naloxone 400 micrograms/ml solution for injection/infusion should not be mixed with preparations containing bisulphite, metabisulphite, long-chain or high-molecular-weight anions, or solutions with an alkaline pH. This medicinal product is for single use only.

Please inspect the medicinal product visually prior to use (also after dilution). Use only clear and colourless solutions practically free from particles.

About this document

Source: MHRA - Medicines and Healthcare products Regulatory Agency (products.mhra.gov.uk) · Marketing authorisation: PL 03551/0109

Last revision stated in the text: July 2024 · MHRA data as of 13 October 2026

Found a mistake? Tell us on the contact page.

The information on this site does not replace the advice of a doctor or pharmacist.

Facts about Naloxone 400 micrograms/ml solution for injection

Prescription needed? Yes, prescription-only medicine (POM)
Active substance Naloxone
Strength 400 micrograms/ml
Pharmaceutical form Solution for injection
Clear and colourless solution
pH: 3.1 – 4.5
Osmolality: 270 - 310 mOsMol/kg
How is it taken Subcutaneous, Intravenous, Intramuscular
Excipients Water for injections, Sodium chloride, Hydrochloric acid, diluted (for pH adjustment)
Pack sizes 10 ampoule
Is it available? Listed as available (NHS Dictionary of Medicines and Devices – not a record of current supplies)
Shelf life 3 years.
Shelf-life after first opening
After first opening the medicinal product should be used immediately.
Shelf-life after dilution
Chemical and physical in-use stability has been demonstrated for 24 hours below 25°C. From the microbiological point of view, the dilutions should be used immediately. If not used immediately, in-use storage times and conditions prior to use are the responsibility of the user and would normally not be longer than 24 hours at 2 to 8 °C,
unless dilution has taken place in controlled and validated aseptic conditions.
Storage Keep the ampoules in the outer carton in order to protect from light. Store below 25°C.
Store diluted solutions below 25°C.
Drug group (ATC) Antidotes
  1. V Various drug classes
    1. V03 All other therapeutic products
      1. V03A All other therapeutic products
        1. V03AB Antidotes
          1. V03AB15 naloxone
Marketing authorisation PL 03551/0109 (first authorised 24 April 2012)
Marketing authorisation holder B. Braun Melsungen AG
Codes GTIN 4030539143332 · BNF 19020700

Sources: the MHRA product information (products.mhra.gov.uk) and the NHS Dictionary of Medicines and Devices (dm+d), release 10.1.0 of 12 October 2026, NHS Business Services Authority. Contains public sector information licensed under the Open Government Licence v3.0.