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NasOpen

Generic name: chlorcyclizine and pseudoephedrine

Brand names: Stahist AD, NasOpen

Used for nasal congestion
Last updated November 3, 2026 0 views
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What is chlorcyclizine-pseudoephedrine?

Chlorcyclizine is an antihistamine that lowers the effects of the natural chemical histamine in the body. Histamine can cause symptoms like sneezing, itching, watery eyes, and a runny nose.

Pseudoephedrine is a decongestant that narrows blood vessels in the nasal passages. Enlarged blood vessels can lead to nasal congestion (stuffy nose).

NasOpen is a combination medicine used to treat runny or stuffy nose, sneezing, itching, watery eyes, sinus congestion, and other cold or allergy symptoms.

NasOpen may also be used for reasons not listed in this medication guide.

This section was rewritten for readability and reviewed for meaning.

How should I take chlorcyclizine-pseudoephedrine?

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Cold medicine is usually taken only for a short time until your symptoms clear up.

Do not give this medication to a child younger than 4 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children.

Measure liquid medicine with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

Call your doctor if your symptoms do not improve after 7 days of treatment, or if you have a fever with a headache, cough, or skin rash.

If you need surgery or medical tests, tell the surgeon or doctor ahead of time if you have taken a cold medicine within the past few days.

Store at room temperature away from moisture and heat. Do not freeze.

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Warnings

Do not use NasOpen if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could happen. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

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Before taking this medicine

You should not use NasOpen if you are allergic to chlorcyclizine or pseudoephedrine.

Do not use NasOpen if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could happen. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

Ask a doctor or pharmacist if it is safe for you to take this medicine if you have other medical conditions, especially:

  • high blood pressure;
  • coronary artery disease (hardened arteries);
  • bladder obstruction or other urination problems; or
  • if you take potassium (Cytra, Epiklor, K-Lyte, K-Phos, Kaon, Klor-Con, Polycitra, Urocit-K).

It is not known whether this medication will harm an unborn baby. Do not use cough or cold medicine without medical advice if you are pregnant.

This medicine may pass into breast milk and may harm a nursing baby. Antihistamines and decongestants may also slow breast milk production. Do not use cough or cold medicine without medical advice if you are breast-feeding a baby.

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Chlorcyclizine-pseudoephedrine side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

NasOpen may cause serious side effects. Stop using NasOpen and call your doctor right away if you have:

  • fast or uneven heart rate;
  • tremor, seizure (convulsions);
  • urinating less than usual or not at all; or
  • dangerously high blood pressure (severe headache, blurred vision, buzzing in your ears, anxiety, confusion, chest pain, uneven heartbeats, seizure).

Common side effects of NasOpen may include:

  • dizziness, drowsiness;
  • constipation;
  • blurred vision; or
  • feeling nervous or restless.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

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What happens if I miss a dose?

Since cold medicine is taken as needed, you might not have a specific dosing schedule. If you are taking the medication regularly and forget a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose. Do not take extra medicine to compensate for the missed dose.

This section was rewritten for readability and reviewed for meaning.

What happens if I overdose?

Seek emergency medical help or call the Poison Help line at 1-800-222-1222.

NasOpen may cause blurred vision and may affect your thinking or reactions. Be cautious if you drive or do anything that requires alertness and clear vision.

Drinking alcohol can increase some side effects of this medication.

Ask a doctor or pharmacist before using any other cold, allergy, cough, or sleep medicine. Antihistamines and decongestants are found in many combination medicines. Taking certain products together can lead to getting too much of a specific drug. Check the label to see if a medicine contains an antihistamine or decongestant.

This section was rewritten for readability and reviewed for meaning.

What other drugs will affect chlorcyclizine-pseudoephedrine?

Ask a doctor or pharmacist before using this medicine if you are also taking any other drugs, including prescription and over-the-counter medicines, vitamins, and herbal products. Some medicines can cause unwanted or dangerous effects when used together. Not all possible interactions are listed in this medication guide.

Taking this medicine with other drugs that make you sleepy or slow your breathing can make these effects worse. Ask your doctor before taking NasOpen with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

This section was rewritten for readability and reviewed for meaning.

Related medicines

Before you take this medicine: the information on this page is general and may not cover your personal circumstances. Read the label supplied with your medicine and ask a pharmacist or doctor if you are unsure, especially if you are pregnant, breastfeeding, taking other medicines or managing a long-term condition.
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Content is provided for education and is not medical advice. See our medical disclaimer.