The reference site for Pirenzepine

Pirenzepine (Gastrozepin), an M1 selective antagonist, is used in the treatment of peptic ulcers, as it reduces gastric acid secretion and reduces muscle spasm.

WHAT IS Pirenzepine?

Pirenzepine is used in the treatment of peptic ulcers, and works by reducing gastric acid secretion as well as relieving muscle cramps or spasms in the stomach, intestines, and bladder.

Pirenzepine is a ‘selective’ antimuscarinic agent which, unlike classic anticholinergic agents, inhibits gastric acid secretion at lower doses than are required to affect gastrointestinal motility, salivary, central nervous system, cardiovascular, ocular and urinary functions.


Brand Name(s): Gastrozepin
CAS nº: 28797-61-7
(peer EN ze peen)


Product Info

The sections below will provide you with more specific information and guidelines related to pirenzepine and its correct use. Please read them carefully.

FDA Information

Pirenzepine is widely used in Europe and Japan for the treatment of peptic ulcer, but not yet approved in the US. A prescription is required for this medicine.

Pirenzepine has been investigated for use in myopia control. It has passed phase I and II of the FDA, and it will be tested in the last phase fairly soon. The FDA is very cautious about this drug since it will be used mostly in children.

Please visit the official site of the FDA for further information.

Why is this medication prescribed?

Pirenzepine is used in the treatment of peptic ulcers, and works by reducing gastric acid secretion as well as relieving muscle cramps or spasms in the stomach, intestines, and bladder.

It is in a class of drugs known as muscarinic receptor antagonists – acetylcholine being the neurotransmitter of the parasympathetic nervous system which initiates the rest-and-digest state (as aposed to fight-or-flight), the result being an increase in gastric motility and digestion.

Other uses for this medicine

Pirenzepine may also be used to prevent nausea, vomiting, and motion sickness.

Additionally, pirenzepine is currently also being investigated for use in myopia control. Please see the section on FDA information for further details.

However, it is important that you talk to your doctor about the possible risks of using this drug for your particular condition.

Dosage and using this medicine

Pirenzepine come as a tablet to be taken orally.

Take this medication as prescribed usually two or three times a day.

Take pirenzepine 1 hour before a meal, with a glass of water.

Do not increase the dose or take this more often than directed. Your condition will not improve any faster but the risk of side effects may be increased.


To treat duodenal or stomach ulcers or intestine problems:

Older adults, adults, and teenagers – 50 milligrams (mg) two times a day, in the morning and at bedtime. Your doctor may change the dose if needed.

Children – Dose must be determined by your doctor.

What special precautions should I follow?


Tell your doctor if you have a history of glaucoma, prostate trouble, heart disease, or any allergies. You may not be able to take pirenzepine, or you may require a dosage adjustment or special monitoring during treatment.

You should also let your doctor know if you have ever had any unusual or allergic reaction to any of the natural belladonna alkaloids or any related products. Also, tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Moreover, please inform your doctor if you are taking any of the following drugs: antacids, diarrhea medicine containing kaolin or attapulgite, ketoconazole (e.g. Nizoral®), central nervous system (CNS) depressants, other anticholinergics, tricyclic antidepressants (amitriptyline [e.g. Elavil®], amoxapine [e.g. Asendin®], clomipramine [e.g. Anafranil®], desipramine [e.g. Pertofrane®], doxepin [e.g. Sinequan®], imipramine [e.g. Tofranil®], nortriptyline [e.g. Aventyl®], protriptyline [e.g. Vivactil®], trimipramine [e.g. Surmontil®]), and potassium chloride (e.g. Kay Ciel®). You may not be able to take pefloxacin, or you may require a dosage adjustment or special monitoring during treatment if you are taking any of the medicines listed above.

Tell your doctor of any over-the-counter or prescription medication you may take. Do not start or stop any medicine without doctor or pharmacist approval.

Additionally, this medication should not be used during pregnancy unless clearly needed. Discuss the risks and benefits with your doctor. Furthermore, it is not known if this medication appears in breast milk. Consult your doctor before breast-feeding.

To avoid dizziness and lightheadedness when rising from a seated or lying position, get up slowly.

Use cautiously performing tasks requiring alertness if this medication causes you to feel drowsy or dizzy.

Avoid intake of alcoholic beverages which will aggravate the sedative effects.

Management of ulcers may often include lifestyle changes such as increased exercise, change in diet, stop smoking and reduction of stress. Discuss the benefits of lifestyle changes with your health care provider.

What should I do if I forget a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule.

It is strongly advised not to take a double dose of this medication in order to make up for a missed one.

What side effects can this medication cause?

Get emergency medical help if you have any of these signs of an allergic reaction:

difficulty breathing
swelling of your face, lips, tongue, or throat

Dry mouth, blurred vision, drowsiness, dizziness, nausea or loss of appetite may occur the first few days as your body adjusts to the medication.

Tell your doctor if any of these symptoms are severe or do not go away:

bitter taste
decreased sexual ability or desire
bad breath

If you experience any of the following symptoms, notify your doctor:

a rapid heart rate
chest pain
skin rash
difficulty urinating
vision changes

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

What storage conditions are needed for this medicine?

Please remember to keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Throw away any medication that is outdated or no longer needed and, if required, talk to your pharmacist about the proper disposal of your medication.

Note: an overdose is especially dangerous in young children.

In case of an emergency/overdose

In the case of an overdose, call your local poison control center on 1-800-222-1222. However, if the victim has collapsed or is not breathing,  then please call the local emergency services on 911.

Symptoms of a pirenzepine overdose may include:

blurred vision or changes in near vision
clumsiness or unsteadiness
convulsions (seizures)
difficulty in breathing, muscle weakness (severe), or tiredness (severe)
drowsiness (severe)
dryness of mouth, nose, or throat (severe)
fast heartbeat
hallucinations (seeing, hearing, or feeling things that are not there)
slurred speech
unusual excitement, nervousness, restlessness, or irritability
unusual warmth, dryness, and flushing of skin

Product Images


Below you will find images and specific information on the principal types of pirenzepine that exist, including their respective brand name(s), strength, inscription codes, manufacturers and/or distributors.

The information below includes general information and guidelines for patients taking this medication and should never be used to substitute professional medical advice that can be provided by a qualified physician or family doctor.

Strength(s): 0.005 G

Contact us