diphenhydrAMINE-phenylephrine (generic name)

Robitussin Cough & Cold Nighttime (brand name)

It is used to treat the symptoms of allergies, a cold, or other sinus problems
(dye fen HYE dra meen; fen il EF rin)
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What is this medicine?

DIPHENHYDRAMINE; PHENYLEPHRINE (dye fen HYE dra meen; fen il EF rin) is a combination of an antihistamine and a decongestant. It is used to treat the symptoms of allergies, a cold, or other sinus problems. It may help with congestion and runny nose. This medicine will not treat an infection.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
  • diabetes
  • glaucoma
  • heart disease
  • high blood pressure
  • phenylketonuria
  • stomach ulcer or obstruction
  • thyroid disease
  • taken an MAOI like Carbex, Eldepryl, Marplan, Nardil, or Parnate within the last 14 days
  • trouble passing urine
  • an unusual or allergic reaction to diphenhydramine, phenylephrine, other medicines, foods, dyes, or preservatives
  • pregnant or trying to get pregnant
  • breast-feeding

How should I use this medicine?

Take this medicine by mouth with a glass of water. Follow the directions on the prescription label. Take your medicine at regular intervals. Do not take it more often than directed.

Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for children as young as 12 years old for selected conditions, precautions do apply.

Patients over 65 years old may have a stronger reaction and need a smaller dose.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What may interact with this medicine?

Do not take this medicine with any of the following medications:
  • bromocriptine
  • ergot alkaloids like dihydroergotamine, ergonovine, ergotamine, methylergonovine
  • MAOIs like Carbex, Eldepryl, Marplan, Nardil, and Parnate
  • stimulant medicines for attention disorders, weight loss, or to stay awake

This medicine may also interact with the following medications:

  • alcohol
  • atropine
  • barbiturates like phenobarbital
  • bretylium
  • caffeine
  • digoxin
  • linezolid
  • mecamylamine
  • medicines for depression, anxiety, or psychotic disturbances
  • medicines for sleep
  • muscle relaxers
  • narcotic medicines for pain
  • other medicines for cold, cough, or allergy
  • procarbazine
  • St. John's Wort
  • theophylline

What should I watch for while using this medicine?

Talk to your doctor or healthcare professional if your symptoms do not start to get better or if they get worse.

This medicine can make you more sensitive to the sun. Keep out of the sun. If you cannot avoid being in the sun, wear protective clothing and use sunscreen. Do not use sun lamps or tanning beds/booths.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:
  • allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
  • anxiety, nervous, or restless
  • breathing problems
  • changes in blood pressure
  • changes in vision
  • fast, irregular heartbeat
  • problems with balance, talking, or walking
  • seizure
  • trouble passing urine or change in the amount of urine
  • unusual bleeding or bruising
  • unusually weak or tired

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

  • dry eyes or mouth
  • headache
  • nausea, vomiting
  • stomach upset
  • trouble sleeping

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Last Updated: April 17, 2009
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