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Omnihist L.A.

Generic Name: chlorpheniramine, methscopolamine, and phenylephrine (KLOR fen IR a meen, METH skoe POL a meen, FEN il EFF rin)
Brand Name: AH-Chew II

What is Omnihist L.A. (chlorpheniramine, methscopolamine, and phenylephrine)?

Chlorpheniramine is an antihistamine that reduces the effects of natural chemical histamine in the body. Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose.

Methscopolamine reduces the secretions of certain organs in the body.

Phenylephrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood vessels can cause nasal congestion (stuffy nose).

Chlorpheniramine, methscopolamine, and phenylephrine is a combination medicine used to treat runny or stuffy nose, sneezing, itching, watery eyes, and sinus congestion caused by allergies, the common cold, or the flu.

Chlorpheniramine, methscopolamine, and phenylephrine may also be used for purposes not listed in this medication guide.

What is the most important information I should know about Omnihist L.A. (chlorpheniramine, methscopolamine, and phenylephrine)?

Do not use this medicine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

What should I discuss with my healthcare provider before taking Omnihist L.A. (chlorpheniramine, methscopolamine, and phenylephrine)?

You should not use this medication if you are allergic to chlorpheniramine, methscopolamine, or phenylephrine.

Do not use this medicine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

Ask a doctor or pharmacist if it is safe for you to take this medicine if you have:

  • asthma or COPD, cough with mucus, or cough caused by smoking, emphysema, or chronic bronchitis;

  • a blockage in your stomach or intestines;

  • kidney or liver disease;

  • high blood pressure, heart disease, coronary artery disease;

  • enlarged prostate or urination problems;

  • glaucoma;

  • pheochromocytoma (an adrenal gland tumor);

  • overactive thyroid; or

  • if you take potassium (Cytra, Epiklor, K-Lyte, K-Phos, Kaon, Klor-Con, Polycitra, Urocit-K).

FDA pregnancy category C. It is not known whether this medicine will harm an unborn baby. Do not use 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 without medical advice if you are breast-feeding a baby.

Artificially sweetened cold medicine may contain phenylalanine. If you have phenylketonuria (PKU), check the medication label to see if the product contains phenylalanine.

How should I take Omnihist L.A. (chlorpheniramine, methscopolamine, and phenylephrine)?

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. This 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.

The chewable tablet must be chewed before you swallow it.

Do not crush, chew, or break an extended-release tablet. Swallow it whole.

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.

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

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.

Store at room temperature away from moisture and heat. Do not allow the liquid form of this medicine to freeze.

What happens if I miss a dose?

Since this medicine is taken when needed, you may not be on a dosing schedule. If you are taking the medication regularly, take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

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

What should I avoid while taking Omnihist L.A. (chlorpheniramine, methscopolamine, and phenylephrine)?

This medicine may cause blurred vision or impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

Drinking alcohol can increase certain side effects of chlorpheniramine.

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

Omnihist L.A. (chlorpheniramine, methscopolamine, and phenylephrine) side effects

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

Stop using this medicine and call your doctor at once if you have:

  • little or no urinating;

  • fast, pounding, or irregular heartbeats;

  • pale skin, weakness, feeling short of breath; or

  • tremors, hallucinations, severe anxiety.

Common side effects may include:

  • blurred vision, headache, dizziness;

  • dry mouth, nose, or throat;

  • nausea; 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.

See also: Side effects (in more detail)

What other drugs will affect Omnihist L.A. (chlorpheniramine, methscopolamine, and phenylephrine)?

Ask a doctor or pharmacist before using this medicine if you are also using 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 worsen these effects. Ask your doctor before taking chlorpheniramine, methscopolamine, and phenylephrine with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

More about Omnihist L.A. (chlorpheniramine / methscopolamine / phenylephrine)

Consumer resources

Related treatment guides

Where can I get more information?

  • Your pharmacist can provide more information about chlorpheniramine, methscopolamine, and phenylephrine.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2012 Cerner Multum, Inc. Version: 2.04. Revision Date: 2013-11-19, 12:16:58 PM.

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