Skip to main content

Atropen (Intramuscular)

Generic name: atropine (intramuscular route) [ AT-roe-peen ]
Drug classes: Anticholinergic chronotropic agents, Anticholinergics / antispasmodics, Antidotes

Medically reviewed by Drugs.com. Last updated on Aug 22, 2022.

Commonly used brand name(s)

In the U.S.

  • Atropen

Available Dosage Forms:

  • Solution

Therapeutic Class: Cholinergic Antagonist

Pharmacologic Class: Antimuscarinic

Uses for Atropen

Atropine injection is used to treat poisoning caused by organophosphorus nerve agents, including organophosphorus or carbamate insecticides.

Atropine is a cholinergic muscarinic antagonist. It works by blocking the chemical acetylcholine, including excess acetylcholine caused by organophosphorus poisoning.

This medicine is to be given only by or under the supervision of your doctor.

Before using Atropen

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of atropine injection in children.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of atropine injection in the elderly. However, elderly patients are more sensitive to the effects of this medicine than younger adults, which may require caution and an adjustment in the dose for patients receiving atropine injection.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Ambenonium
  • Potassium
  • Potassium Citrate

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Amifampridine
  • Bupropion
  • Clozapine
  • Donepezil
  • Glucagon
  • Glycopyrrolate
  • Glycopyrronium Tosylate
  • Macimorelin
  • Methacholine
  • Revefenacin
  • Scopolamine
  • Secretin Human
  • Tiotropium

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Arbutamine

Interactions with food/tobacco/alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other medical problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Heart disease (eg, recent heart attack, severe coronary artery disease) or
  • Lung disease or
  • Narrow angle glaucoma, severe or
  • Stomach or bowel problems (eg, pyloric stenosis) or
  • Trouble urinating (eg, bladder blockage)—Use with caution. May make these conditions worse.

Proper use of Atropen

A nurse or other trained health professional will give you this medicine. You may also be taught how to give your medicine at home. This medicine is given as a shot into a muscle, usually in the outer thigh.

To use the 0.5 mg, 1 mg, and 2 mg atropine autoinjector:

  • Snap the end of the plastic sleeve down and over the yellow safety release. Remove the autoinjector from the plastic sleeve. Do not place fingers on the green tip.
  • Hold the autoinjector firmly with the green tip pointed down. With your other hand, pull off the yellow safety release.
  • Aim and firmly poke the green tip straight down at 90 degrees angle against the outer thigh. This autoinjector can inject through clothing, but make sure pockets at the injection site are empty. For children and thin people, bunch up the thigh to provide thicker area for injection.
  • Hold the autoinjector in place for at least 10 seconds to allow injection to finish.
  • Remove the autoinjector and massage the injection site for few seconds.

To use the 0.25 mg atropine autoinjector:

  • Remove the plastic cap from the yellow tube and slide the autoinjector from the tube. Do not place fingers on the black tip.
  • Hold the autoinjector firmly with the black tip pointed down. With your other hand, pull off the gray safety release.
  • Aim and firmly poke the black tip straight down at 90 degrees angle against the outer thigh. This autoinjector can inject through clothing, but make sure pockets at the injection site are empty. For children and thin people, bunch up the thigh to provide thicker area for injection.
  • Hold the autoinjector in place for at least 10 seconds to allow injection to finish.
  • Remove the autoinjector and massage the injection site for few seconds.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For injection dosage form (autoinjector):
    • For treatment of organophosphorus poisoning:
      • Adults and children older than 10 years of age weighing more than 41 kilograms (kg)—2 milligrams (mg) injected into a muscle.
      • Children 4 to 10 years of age weighing 18 to 41 kg—1 mg injected into a muscle.
      • Children 6 months to 4 years of age weighing 7 to 18 kg—0.5 mg injected into a muscle.
      • Children younger than 6 months of age weighing less than 7 kg—0.25 mg injected into a muscle.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions while using Atropen

Your doctor will check your progress closely while you or your child are receiving this medicine. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to receive it. Blood and urine tests may be needed to check for unwanted effects.

This medicine may cause heart problems. Check with your doctor right away if you or your child have chest pain or discomfort, dizziness, fainting, fast, slow, or irregular heartbeat, lightheadedness, or pounding or rapid pulse.

This medicine may make you sweat less, which can cause your body temperature to rise. Be careful when you exercise and during hot weather. You could overheat or get heat stroke. Check with your doctor right away if you or your child have dizziness, fast, shallow breathing, fast, weak heartbeat, headache, muscle cramps, pale, clammy skin, thirst, or extremely high fever or body temperature.

This medicine may cause eye problems, including acute glaucoma. Check with your doctor right away if you or your child have blindness, blurred vision, decreased vision, eye pain, headache, nausea or vomiting, or tearing. Your doctor may want you to have your eyes checked by an ophthalmologist (eye doctor).

This medicine may cause urinary retention (trouble passing urine or not fully emptying the bladder). Check with your doctor right away if you or your child have decreased in urine volume, decreased in frequency of urination, difficulty in passing urine, or painful urination.

Check with your doctor right away if you or your child have constipation, nausea, vomiting, or stomach pain. These may be symptoms of a serious stomach or bowel problem (eg, blockage).

This medicine may cause lung or breathing problems. Tell your doctor right away if you have an increase or thickening of mucous from the lungs.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and require immediate medical attention. Check with your doctor right away if you or your child have cough, difficulty swallowing, dizziness, fast heartbeat, hives, itching, puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue, skin rash, tightness in the chest, trouble breathing, or unusual tiredness or weakness.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Atropen side effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

  • Bigger, dilated, or enlarged pupils
  • blindness
  • blurred vision
  • chest pain, discomfort, or tightness
  • cough
  • decreased vision
  • decrease in urine volume
  • decrease in frequency of urination
  • difficulty in passing urine
  • difficulty swallowing
  • dizziness
  • eye pain
  • extremely high fever or body temperature
  • fainting
  • fast, shallow breathing
  • fast, slow, or irregular heartbeat
  • fast, weak heartbeat
  • headache
  • hives, itching, skin rash
  • increase in mucous from lungs
  • lightheadedness
  • muscle cramps
  • nausea or vomiting
  • pain at the injection site
  • painful urination
  • pale, clammy skin
  • pounding or rapid pulse
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • stomach pain
  • tearing
  • thirst
  • trouble breathing
  • unusual tiredness or weakness

Less common

  • Decreased awareness or responsiveness
  • dryness or soreness of the throat
  • excessive muscle tone
  • hoarseness
  • loss of memory
  • muscle stiffness, tension, or tightness
  • overactive reflexes
  • problems with memory
  • seizures
  • severe sleepiness
  • shakiness and unsteady walk
  • unsteadiness, trembling or other problems with muscle control or coordination
  • voice changes

Incidence not known

  • Change in color vision
  • confusion
  • difficulty seeing at night
  • discouragement
  • dry eyes
  • dry mouth
  • feeling sad or empty
  • hallucinations
  • holding false beliefs that cannot be changed by fact
  • increased sensitivity of the eyes to sunlight
  • lack of appetite
  • loss of interest or pleasure
  • shakiness in the legs, arms, hands, or feet
  • trembling or shaking of the hands or feet
  • trouble concentrating
  • trouble sleeping
  • unusual excitement, nervousness, or restlessness

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known

  • Bloating
  • constipation
  • diarrhea
  • impotence
  • loss of libido
  • small or red spots on the skin

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Further information

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