Autoject (Combopen) Nerve Agent Antidote L4a1


2mg atropine sulphate, 500mg pralidoxime methane sulphonate and 10mg avizafone in 2ml aqueous solution.

Read all of this leaflet carefully before you use Autoject (ComboPen®) Nerve Agent Antidote L4A1

Keep this leaflet. You may need to read it again.

If you have any questions or are in doubt about anything or require further information, please ask your doctor or medical officer.

If any of the side effects get serious, or if you notice any side-effects not listed in this leaflet, please tell your doctor or medical officer.

In this leaflet:

1.    What ComboPen is and what it is used for

2.    Before you use ComboPen

3.    How to use ComboPen

4.    Possible side-effects

5.    How to store ComboPen

6.    Further information


The ComboPen contains drugs called atropine sulphate, pralidoxime methane sulphonate and avizafone which together are an antidote to poisoning following exposure to nerve agents.

You must use the Autoject (ComboPen) Nerve Agent Antidote exactly as you were trained. The label on the sleeve also tells you how to use the nerve agent antidote.

You may also have been taking NAPS L1A1, a nerve agent antidote pre-treatment.

2.    BEFORE YOU USE COMBOPEN Do not use your ComboPen:

•    if you are allergic to atropine, avizafone or pralidoxime or any of the other ingredients in the ComboPen (see Section 6 for other ingredients)

   on children or older people

If you think you may be allergic, ask your doctor or medical officer for advice.

Taking other medicines:

No interaction has been reported between the drugs in ComboPen and NAPS or other medicines.

Therefore it is safe to use ComboPen if you are taking or have received:

•    anti-malarials

•    antibiotics

•    vaccines

•    NAPS tablets (nerve agent antidote pre-treatment)

Women may also be taking the contraceptive pill.

Pregnancy and breast-feeding:

The effects of ComboPen in pregnant women are not known, therefore the use of the ComboPen is not recommended. If you do become pregnant, you should consult your doctor or medical officer.

It is not known if the ingredients of ComboPen pass into breast milk, so if you are currently breastfeeding you should tell your doctor.

Driving and using machines:

Take special care when driving or using machines if you have side-effects such as loss of coordination, tiredness, drowsiness or sedation.


Always use your ComboPen exactly as you have been trained.

Your ComboPen is an auto-injection device which enables you to give the medicine to yourself.

Each ComboPen contains one dose which is self-injected into your thigh muscle through your clothing.

To use a ComboPen

•    Pull out grey safety cap from end of automatic injector

•    Place black end of the ComboPen on your thigh over your clothing, making sure there is nothing between your clothing and your skin

•    Press hard until the injector functions - you will feel the needle when this happens

•    Count to ten slowly and then withdraw the ComboPen. Note the time

•    Bend the needle over and place in your haversack; hand any used ComboPens to the Quartermaster's department as soon as possible for safe disposal.

If nerve agent poisoning symptoms persist, the dose can be repeated with another ComboPen at 15 minute intervals with a maximum total dose of three injections.

If you are still suffering from symptoms of nerve agent poisoning after using the 3 doses, additional treatment will be given by the Medical Services.

If you use more ComboPens than you should:

If you have been exposed to nerve agents you are classified as a casualty and are unlikely to receive more than the recommended maximum dose of 3 ComboPen injections on any one occasion.


Like all medicines, the ComboPen can have side-effects, although not everybody gets them.

The most common side effects are:

•    drowsiness

•    redness or swelling of the eyelids

•    difficulty in focusing

•    clumsiness and unsteadiness on standing

•    feelings of disorientation

•    sedation.

If any of the side-effects get serious, or if you notice any side-effects not listed in this leaflet, please tell your doctor or medical officer.

If you use ComboPen by mistake, without being exposed to nerve agents, you may feel anxious, euphoric, restless and delirious and in severe cases go into a coma. You may also get a dry mouth, hot dry skin, rapid pulse and have difficulty in passing water (urinary retention).

If this happens to you, you must get help from a medical officer who will treat you for atropine overdose.


Keep out of reach and sight of children.

Do not use ComboPen after the expiry date which is printed on the label after “exp". The expiry date refers to the last day of the month.

Store at 2°C - 8°C (in a refrigerator)

You may keep your ComboPen for up to six months out of the refrigerator.

Return any used or unused ComboPen(s) to the Quartermaster's department for disposal as soon as possible. Do not dispose of via wastewater or household waste. These measures will help to protect the environment.

6.    FURTHER INFORMATION What ComboPen contains

The active substances are: atropine sulphate (2mg), pralidoxime methane sulphonate (500mg) and avizafone (10mg).

The other ingredients are: citric acid monohydrate and water for injections. Sodium hydroxide or sulphuric acid may be added to adjust the pH.

What ComboPen looks like

ComboPen is a cylindrically shaped device, which contains a clear colourless to slightly yellow sterile solution in a colourless glass tube, sealed with a rubber plunger and diaphragm. The device has one flat end with a grey safety cap and a pointed black end.

Marketing Authorisation Holder and Manufacturing Authorisation Holder

The Marketing Authorisation Holder is the Secretary of State for Defence, Ministry of Defence, Main Building, Whitehall, London SW1 2HB United Kingdom.

The manufacturer of ComboPen is the Medical and General Supplies Team,

Building 08, HPA, Porton Down, Salisbury, SP40JG.

This leaflet was last approved in 08/2009.