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Phena-S

Generic name: chlorpheniramine, phenylephrine, and pyrilamine

Brand names: Chlorex-A 12, Conal, Nalex A 12, MyHist-PD, Phena-Plus, Phena-S, Poly Hist PD (old formulation), Ru-Hist Forte

Last updated November 3, 2026 0 views
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What is Phena-S?

Phena-S is a combination medicine that helps relieve symptoms from coughs, colds, and allergies.

Phena-S may also be used for other reasons not mentioned in this medication guide.

This section was rewritten for readability and reviewed for meaning.

How should I take Phena-S?

Use exactly as directed on the label, or as prescribed by your doctor. Cold or cough medicine is only for short-term use.

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.

Do not give this medication to a child younger than 6 years old. Always ask a doctor before giving a cough or cold medicine to a child.

Follow all directions when giving Phena-S to a child. Do not use the medicine to make a child sleepy. Misuse of this medicine may cause death in very young children.

Shake the oral suspension (liquid). Measure a dose with the supplied measuring device (not a kitchen spoon).

Store at room temperature away from moisture, heat, and light.

This section was rewritten for readability and reviewed for meaning.

Warnings

You should not use Phena-S if you have severe coronary artery disease, diabetes, an overactive thyroid, asthma, pneumonia, or other breathing problems.

Do not use Phena-S if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, and tranylcypromine.

Do not give this medicine to a child younger than 6 years old. Misuse of this medicine may cause death in very young children.

Do not use this medicine to make a child sleepy.

This section was rewritten for readability and reviewed for meaning.

Before taking this medicine

Do not use Phena-S 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, and tranylcypromine. Wait at least 14 days after stopping an MAO inhibitor before you take this medicine.

You should not use this medicine if you are allergic to chlorpheniramine, phenylephrine, pyrilamine, or other decongestants, or if you have:

  • severe coronary artery disease;
  • diabetes;
  • overactive thyroid; or
  • asthma, pneumonia, or other breathing problems.

Tell your doctor if you have ever had:

  • heart disease or high blood pressure;
  • blood circulation problems;
  • glaucoma;
  • an ulcer or blockage in the stomach;
  • enlarged prostate;
  • bladder blockage or other urination problems; or
  • a history of seizures.

Tell your doctor if you are pregnant or breastfeeding.

This section was rewritten for readability and reviewed for meaning.

Phena-S side effects

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

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

  • confusion, hallucinations;
  • feeling nervous or irritable;
  • trouble sleeping;
  • little or no urination;
  • a seizure (convulsions);
  • numbness or tingling;
  • feeling light-headed, like you might pass out;
  • pounding heartbeats or fluttering in your chest; or
  • severe headache, blurred vision, pounding in your neck or ears.

Serious side effects may be more common in older adults.

Common side effects of Phena-S may include:

  • nausea, constipation, loss of appetite;
  • rash or itching;
  • increased sweating;
  • dry mouth, nose, or throat;
  • blurred vision;
  • headache, dizziness; or
  • feeling restless or excited (especially in children).

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

This section was rewritten for readability and reviewed for meaning.

What happens if I miss a dose?

Take the medicine as soon as you can, but if it's almost time for your next dose, skip the missed dose. Do not take two doses at the same time.

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. An overdose can be fatal.

Overdose symptoms may include dry mouth, extreme drowsiness, confusion, ringing in your ears, tremors, seizure, dilated pupils, vomiting, and loss of consciousness.

Phena-S may cause blurred vision and may affect your reactions. Avoid driving or doing anything dangerous until you know how this medicine will affect you.

Drinking alcohol with this medicine can lead to side effects.

Ask a doctor or pharmacist before taking other cough or cold medicines that may have similar ingredients.

Phena-S could make you more likely to get sunburned. Stay away from sunlight or tanning beds. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

This section was rewritten for readability and reviewed for meaning.

What other drugs will affect Phena-S?

Using Phena-S with other medications that cause drowsiness or slow your breathing can make this effect worse. Talk to your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

Other medications may interact with Phena-S, including prescription and over-the-counter medicines, vitamins, and herbal products. Inform your doctor about all other medicines you are taking.

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.