Skip to Content

Thonzylamine and phenylephrine

Generic Name: thonzylamine and phenylephrine (thon-ZIL-a-meen/FEN-il-EF-rin)
Brand Name: Nasopen PE

Thonzylamine and phenylephrine is used for:

Relieving symptoms of sinus congestion, pressure, runny nose, itching of the nose or throat, itchy and watery eyes, and sneezing due to colds, upper respiratory infections, and allergies. It may also be used for other conditions as determined by your doctor.

Thonzylamine and phenylephrine is an antihistamine and decongestant combination. The antihistamine works by blocking the action of histamine, which helps reduce symptoms such as watery eyes and sneezing. The decongestant promotes sinus and nasal drainage, which relieves congestion and pressure.

Do NOT use thonzylamine and phenylephrine if:

  • you are allergic to any ingredient in thonzylamine and phenylephrine
  • you have severe high blood pressure, severe heart blood vessel disease, rapid heartbeat, or severe heart problems
  • you take sodium oxybate (GHB) or if you have taken furazolidone or a monoamine oxidase inhibitor (MAOI) (eg, phenelzine) within the last 14 days

Contact your doctor or health care provider right away if any of these apply to you.

Before using thonzylamine and phenylephrine:

Some medical conditions may interact with thonzylamine and phenylephrine. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances
  • if you have a fast, slow, or irregular heartbeat
  • if you have a history of asthma; lung or breathing problems (eg, chronic bronchitis, emphysema); adrenal gland problems (eg, adrenal gland tumor); heart problems; high blood pressure; diabetes; heart blood vessel problems; stroke; glaucoma; a blockage of your bladder, stomach, or bowels; ulcers; trouble urinating; an enlarged prostate; seizures; or an overactive thyroid

Some MEDICINES MAY INTERACT with thonzylamine and phenylephrine. Tell your health care provider if you are taking any other medicines, especially any of the following:

  • Beta-blockers (eg, propranolol), catechol-O-methyltransferase (COMT) inhibitors (eg, tolcapone), furazolidone, indomethacin, MAOIs (eg, phenelzine), sodium oxybate (GHB), or tricyclic antidepressants (eg, amitriptyline) because side effects of thonzylamine and phenylephrine may be increased
  • Digoxin or droxidopa because risk of irregular heartbeat or heart attack may be increased
  • Bromocriptine or hydantoins (eg, phenytoin) because side effects may be increased by thonzylamine and phenylephrine
  • Guanadrel, guanethidine, mecamylamine, methyldopa, or reserpine because effectiveness may be decreased by thonzylamine and phenylephrine

This may not be a complete list of all interactions that may occur. Ask your health care provider if thonzylamine and phenylephrine may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use thonzylamine and phenylephrine:

Use thonzylamine and phenylephrine as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Thonzylamine and phenylephrine may be taken with or without food.
  • Use a measuring device marked for medicine dosing. Ask your pharmacist for help if you are unsure of how to measure your dose.
  • If you miss a dose of thonzylamine and phenylephrine and you are taking it regularly, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use thonzylamine and phenylephrine.

Important safety information:

  • Thonzylamine and phenylephrine may cause dizziness, drowsiness, or blurred vision. These effects may be worse if you take it with alcohol or certain medicines. Use thonzylamine and phenylephrine with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
  • Do not drink alcohol while you are taking thonzylamine and phenylephrine.
  • Check with your doctor before you use medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you are using thonzylamine and phenylephrine; it may add to their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.
  • Do not take diet or appetite control medicines while you are taking thonzylamine and phenylephrine without checking with your doctor.
  • Thonzylamine and phenylephrine has an antihistamine and a decongestant in it. Before you start any new medicine, check the label to see if it has an antihistamine or a decongestant in it too. If it does or if you are not sure, check with your doctor or pharmacist.
  • Do NOT take more than the recommended dose or use for longer than recommended without checking with your doctor.
  • If your symptoms do not improve within 5 to 7 days or if they become worse, check with your doctor.
  • Thonzylamine and phenylephrine may cause increased sensitivity to the sun. Avoid exposure to the sun, sunlamps, or tanning booths until you know how you react to thonzylamine and phenylephrine. Use a sunscreen or protective clothing if you must be outside for a prolonged period.
  • Thonzylamine and phenylephrine may interfere with skin allergy tests. If you are scheduled for a skin test, talk to your doctor. You may need to stop taking thonzylamine and phenylephrine for a few days before the tests.
  • Tell your doctor or dentist that you take thonzylamine and phenylephrine before you receive any medical or dental care, emergency care, or surgery.
  • Use thonzylamine and phenylephrine with caution in the ELDERLY; they may be more sensitive to its effects.
  • Caution is advised when using thonzylamine and phenylephrine in CHILDREN; they may be more sensitive to its effects.
  • Thonzylamine and phenylephrine should not be used in CHILDREN younger than 6 years old without first checking with the child's doctor; safety and effectiveness in these children have not been confirmed.
  • PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using thonzylamine and phenylephrine while you are pregnant. It is not known if this medicine is found in breast milk. If you are or will be breast-feeding while you use thonzylamine and phenylephrine, check with your doctor. Discuss any possible risks to your baby.

Possible side effects of thonzylamine and phenylephrine:

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Constipation; diarrhea; dizziness; drowsiness; excitability; headache; loss of appetite; nausea; nervousness or anxiety; trouble sleeping; upset stomach; vomiting; weakness.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); difficulty urinating or inability to urinate; fast or irregular heartbeat; hallucinations; seizures; severe dizziness, light-headedness, or headache; tremor; trouble sleeping; vision changes.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately.

Proper storage of thonzylamine and phenylephrine:

Store thonzylamine and phenylephrine at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep thonzylamine and phenylephrine out of the reach of children and away from pets.

General information:

  • If you have any questions about thonzylamine and phenylephrine, please talk with your doctor, pharmacist, or other health care provider.
  • Thonzylamine and phenylephrine is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.
  • Check with your pharmacist about how to dispose of unused medicine.

This information should not be used to decide whether or not to take thonzylamine and phenylephrine or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about thonzylamine and phenylephrine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to thonzylamine and phenylephrine. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using thonzylamine and phenylephrine.

Review Date: August 8, 2016

Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using this medicine.

More about phenylephrine/thonzylamine

Consumer resources

Related treatment guides

Hide