Antaxone

Patient Information Leaflet

ANTAXONE 50 mg hard capsules, 50 mg/10 ml oral solution, 100 mg/20 ml oral solution

Naltrexone hydrochloride
Please read this leaflet carefully before taking this medicine because it contains important information for you.

• Keep this leaflet. You may need to read it again.
• If you have any questions, ask your doctor or pharmacist.
• This medicine has been prescribed for you only. Do not give it to other people, even if they have the same symptoms as you, because it could be harmful.
• If you experience any side effects, including those not listed in this leaflet, talk to your doctor or pharmacist. See section 4.

Contents of this leaflet:

1. What ANTAXONE is and what it is used for
2. What you need to know before taking ANTAXONE
3. How to take ANTAXONE
4. Possible side effects
5. How to store ANTAXONE
6. Contents of the pack and other information

1. What ANTAXONE is and what it is used for

ANTAXONE contains the active substance naltrexone hydrochloride, which belongs to a group of medicines
called opioid antagonists, used in substance dependence disorders (such as heroin) to block
the effects of opioid-derived drugs such as heroin.
ANTAXONE is indicated for the treatment of opioid dependence in individuals who wish to begin a detoxification program and who have not taken opioid substances for at least 7–10 days.

2. What you must know before taking ANTAXONE

Do not take ANTAXONE

• if you are allergic to hydrochloride naltrexone or to any of the other ingredients of this medicine (listed in section 6);
• if you are taking medicines containing opioids (see section “Other medicines and ANTAXONE”);
• if you suffer from opioid dependence or are experiencing opioid withdrawal symptoms;
• if urine tests or the naloxone test show that you have taken opioids (see section “How to take ANTAXONE”);
• if you suffer from severe liver problems (acute hepatitis, liver failure);
• if you suffer from severe kidney problems (severe renal failure);
• if you are pregnant or breastfeeding (see section “Pregnancy and breastfeeding”);
• if the person who is to take this medicine is under 18 years of age (see section “Children and adolescents”);
• if you are taking methadone (see section “Other medicines and ANTAXONE”).

Warnings and precautions
Talk to your doctor before taking ANTAXONE.

During treatment with this medicine, you must be monitored regularly by a doctor specialized in treating opioid addiction. Your doctor may provide you with an identification card to show in case you need medical treatment or emergency care.

Take this medicine with great caution and inform your doctor:

• if you suffer from liver or kidney problems (impaired renal or hepatic function);
• if you have recently taken opioid substances;
• if you are being treated with medicines belonging to the opioid group, used for example for cough, cold or diarrhea;
• if you are taking any other medicine listed in the section “Other medicines and ANTAXONE”.

Before starting treatment with ANTAXONE, your doctor will check:

• your liver function. If your doctor considers it appropriate to start treatment with this medicine, you must undergo monthly blood tests and examinations for the first 6 months to monitor liver function; your doctor will determine the frequency of tests and examinations thereafter;
• that you have not taken opioid substances for at least 5–7 days in the case of heroin, and at least 10 days in the case of methadone (naloxone test). If you have recently taken opioid substances, taking ANTAXONE may cause withdrawal symptoms, which may appear within 5 minutes after taking the medicine and may last up to 2 days, with symptoms such as:
  • confusion;
  • drowsiness;
  • hallucinations;
  • diarrhea;
  • vomiting.

If such symptoms occur, your doctor will provide appropriate treatment, which may include administration of intravenous fluids and supportive therapy based on your condition.

WARNING: do not take heroin or other opioid substances during treatment with ANTAXONE, even in small doses, because they will not produce euphoric effects and may cause severe poisoning with symptoms such as:
respiratory depression (breathing difficulty), sudden loss of heart and blood vessel function (cardiocirculatory collapse), and death. However, if such substances are needed to control pain, your doctor must determine the appropriate dose based on the patient’s needs.

Doses of ANTAXONE higher than those prescribed by your doctor may cause serious liver damage (hepatocellular injury).

This medicine does not reduce the risk of suicide in drug users who may be depressed.

Children and adolescents
The use of ANTAXONE is contraindicated in children and adolescents due to lack of data on safety and efficacy. Therefore, ANTAXONE must not be used in children and adolescents under 18 years of age (see section “Do not take ANTAXONE”).

Elderly
There are no efficacy and safety data available for the use of ANTAXONE in elderly patients.

Other medicines and ANTAXONE
Tell your doctor if you are taking, have recently taken or might take any other medicine.

ANTAXONE must not be administered together with certain medicines. Therefore, inform your doctor if you are taking:

• medicines used for cough, cold or diarrhea (belonging to the opioid group) (see section “Do not take ANTAXONE”);
• medicines used to relieve pain (opioid-derived analgesics);
• medicines used to counteract acute opioid intoxication and for the treatment of drug dependence (opioid antagonists);
• medicines used for high blood pressure (central antihypertensives, alpha-methyldopa);
• methadone in substitution therapy, due to the risk of withdrawal symptoms (see section “Do not take ANTAXONE”).

Use caution and inform your doctor if you are taking medicines used:

• for anxiety, sedation or sleep (barbiturates, benzodiazepines, meprobamate);
• for depression (amitriptyline, doxepin, mianserine, trimipramine);
• for allergies (H1 antihistamines);
• to relieve excessive muscle tension (baclofen);
• for the treatment of leprosy and certain types of cancer (thalidomide);
• for mental disorders (thioridazine), because when taken together with ANTAXONE, it may cause drowsiness and muscle weakness (asthenia);
• for psychiatric disorders (droperidol). In alcohol-dependent subjects not seeking treatment, administration of ANTAXONE significantly increases plasma levels of acamprosate.

Pregnancy and breastfeeding
If you are pregnant, think you may be pregnant or are planning to become pregnant, or if you are breastfeeding, consult your doctor or pharmacist before taking this medicine.

If you are pregnant, take ANTAXONE only if strictly necessary and under direct medical supervision. Do not breastfeed while taking this medicine.

Driving and using machines
This medicine may impair your ability to drive or operate machinery. Therefore, avoid driving or operating machinery while taking ANTAXONE.

ANTAXONE capsules contain lactose
This medicine contains lactose, a type of sugar. If your doctor has diagnosed you with an intolerance to certain sugars, contact your doctor before taking this medicine.

ANTAXONE oral solution contains:

• parahydroxybenzoates, which may cause allergic reactions (including delayed reactions).
• sorbitol (7 g per container of Antaxone 100 mg/20 ml and 3.5 g per container of Antaxone 50 mg/10 ml). Sorbitol is a source of fructose. If your doctor has told you that you are intolerant to certain sugars, or if you have been diagnosed with hereditary fructose intolerance, a rare genetic disorder in which patients cannot metabolize fructose, speak with your doctor before taking this medicine. It may cause gastrointestinal problems and has a mild laxative effect.
• 12.4 mg of alcohol (ethanol) in each 10 ml (0.01% w/v). The amount of alcohol in a dose of this medicine is equivalent to less than 1 ml of beer or 1 ml of wine. The small amount of alcohol in this medicine will not produce significant effects.
• Glucose. If your doctor has diagnosed you with an intolerance to certain sugars, contact your doctor before taking this medicine.

3. How to take ANTAXONE

Take this medicine exactly as directed by your doctor. If you have any doubts, consult your doctor.
Treatment with ANTAXONE must always begin in specialized clinics for the treatment of drug addiction (substance dependence), and may then continue under the close supervision of physicians at such centers.
Before taking ANTAXONE, you must not have taken opioid substances for at least 7–10 days. Your doctor may prescribe certain tests (urine analysis, naloxone test) to confirm the absence of these substances in your body (see section “What you need to know before taking ANTAXONE”).
The recommended starting dose at the beginning of treatment is 20–25 mg of ANTAXONE.
If withdrawal symptoms do not appear within one hour, your doctor may decide to proceed with maintenance therapy, which may consist of one of the following regimens:

• 50 mg daily;
• 50 mg from Monday to Friday and 100 mg on Saturday;
• 100 mg on alternate days;
• 150 mg every 3 days;
• 100 mg on Monday, 100 mg on Wednesday, and 150 mg on Friday.

It is recommended not to exceed the recommended maximum dose of 150 mg per day, as a higher incidence of adverse effects has been observed.

The oral solution is intended for individuals who previously used the drug in capsule or tablet form.

If you take more ANTAXONE than you should
In case of accidental overdose or ingestion of an excessive amount of this medicine, seek immediate medical attention from your doctor or the nearest hospital.

If you forget to take ANTAXONE
If you forget to take ANTAXONE, do not take a double dose to make up for the missed dose.
If you have any questions about the use of this medicine, consult your doctor or pharmacist.

4. Possible side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them.
Stop using opioid substances before taking this medicine, as ANTAXONE may worsen withdrawal symptoms.
The following side effects may occur:

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

• sleep disturbance, anxiety, nervousness, headache, restlessness;
• abdominal pain, nausea and vomiting;
• muscle pain (myalgia) and joint pain (arthralgia);
• weakness (asthenia).

Common (may affect up to 1 in 10 people)

• loss of appetite;
• irritability, behavioural disorders (affective disorders);
• dizziness;
• increased tearing;
• increased awareness of heartbeat (palpitations), increased heart rate (tachycardia), and heart problems (ECG changes);
• chest pain;
• diarrhoea, constipation (stipsis);
• skin irritation (erythema);
• sexual and fertility problems in men (erectile dysfunction, delayed ejaculation);
• thirst, fatigue, chills, increased energy, and excessive sweating (hyperhidrosis).

Uncommon (may affect up to 1 in 100 people)

• enlarged lymph nodes (lymphadenopathy);
• increased appetite;
• disturbances in sexual desire (increased libido, decreased libido), depression, paranoia, agitation, confusion, disorientation, hallucinations, nightmares, and abnormal dreams;
• tremors, drowsiness;
• blurred vision, sensitivity to light (photophobia), eye irritation, swelling (tumefaction), eye pain and eye strain;
• ear discomfort and pain, perception of ringing in the ear (tinnitus), vertigo;
• inflammation of veins (phlebitis), hot flushes, facial redness (flushing), changes in blood pressure (fluctuation in arterial pressure);
• mucus accumulation (congestion) and nasal discomfort, increased mucus production, runny nose (rhinorrhoea), sneezing, nasal disorders (sinus pain), nosebleeds (epistaxis), difficulty breathing (dyspnoea), sore throat and pharynx (oropharyngeal pain), loss of voice (dysphonia), cough, yawning;
• flatulence, haemorrhoids, dry mouth, stomach and intestinal perforation (ulcer);
• liver problems and inflammation (abnormal liver function tests, increased bilirubin in blood, increased liver transaminases, hepatitis);
• itching, increased sebum production (seborrhoea), acne, hair loss (alopecia);
• muscle and bone pain, particularly in arms and legs, muscle cramps, groin pain;
• passing small amounts of urine frequently (pollakiuria), problems urinating (urinary disorders);
• cold sores (herpes labialis), fungal skin infection of the foot (dermatophytosis);
• gland swelling, general pain, skin swelling due to fluid accumulation, fever (pyrexia), cold sensation in arms and legs, hot sensation, weight gain or loss;
• increased blood pressure, heart problems (abnormal electrocardiogram).

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

• a disease characterised by reduced platelet count in blood and skin redness with bleeding (idiopathic thrombocytopenic purpura);
• suicidal thoughts and attempts;
• painful and prolonged erection (priapism);
• withdrawal syndrome.

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

• allergic reactions (hypersensitivity);
• severe muscle damage (rhabdomyolysis).

Reporting of side effects
If you experience any side effect, including those not listed in this leaflet, tell your doctor or pharmacist.
You can also report side effects directly via the national reporting system at the following address: https://www.aifa.gov.it/content/segnalazioni-reazioni-avverse.
By reporting side effects, you can help provide more information on the safety of this medicine.

5. How to store ANTAXONE

Keep this medicine out of the sight and reach of children.
Do not use this medicine after the expiry date stated on the pack after "Exp.".
The expiry date refers to the last day of that month and applies to the product in its original, unopened
packaging and properly stored.
Store the capsules at a temperature below 30 °C.
Do not dispose of any medicine via wastewater or household waste. Ask your pharmacist how to dispose of
medicines you no longer use. This will help protect the environment.

6. Package contents and other information

What ANTAXONE 50 mg hard capsules contains

• The active substance is naltrexone hydrochloride. One capsule contains 50 mg of naltrexone hydrochloride.
• The other components are: lactose, magnesium stearate, gelatin, titanium dioxide (E171), indigotine (E132).

What ANTAXONE 50 mg/10 ml oral solution contains

• The active substance is naltrexone hydrochloride. One container contains 50 mg of naltrexone hydrochloride.
• The other components are: sorbitol 70%, bitter flavour 1631 (containing: ethanol, sorbitol and glucose), saccharin, methyl hydroxybenzoate, propyl hydroxybenzoate, purified water.

What ANTAXONE 100 mg/20 ml oral solution contains

• The active substance is naltrexone hydrochloride. One container contains 100 mg of naltrexone hydrochloride.
• The other components are: sorbitol 70%, bitter flavour 1631 (containing: ethanol, sorbitol and glucose), saccharin, methyl hydroxybenzoate, propyl hydroxybenzoate, purified water.

Description of the appearance of ANTAXONE and the contents of the pack

50 mg hard capsules: carton containing 14 capsules.
50 mg/10 ml oral solution: carton containing 10 single-dose containers of 50 mg.
100 mg/20 ml oral solution: carton containing 5 single-dose containers of 100 mg.

Marketing Authorisation Holder and Manufacturer
Marketing Authorisation Holder
ZAMBON ITALIA s.r.l.
Via Lillo del Duca 10
20091 Bresso (MI)
Italy
Manufacturer
ZAMBON S.p.A.
Via della Chimica 9
Vicenza
Italy