Why is Phenergan prescribed?
Phenergan is an antihistamine that relieves nasal stuffiness and inflammation and red, inflamed eyes caused by hay fever and other allergies. It is also used to treat itching, swelling, and redness from hives and other rashes; allergic reactions to blood transfusions; and, with other medications, anaphylactic shock (severe allergic reaction).
Phenergan is also used as a sedative and sleep aid for both children and adults, and is prescribed to prevent and control nausea and vomiting before and after surgery and to prevent and treat motion sickness. It is also used, with other medications, for pain after surgery.
Antihistamines work by decreasing the effects of histamine, a chemical the body releases in response to certain irritants. Histamine narrows air passages in the lungs and contributes to inflammation. Antihistamines reduce itching and swelling and dry up secretions from the nose, eyes, and throat.
Most important fact about Phenergan
Phenergan may cause considerable drowsiness. You should not drive or operate dangerous machinery or participate in any hazardous activity that requires full mental alertness until you know how you react to Phenergan. Children should be carefully supervised while they are bike-riding, roller-skating, or playing until the drug's effect on them is established.
How should you take Phenergan?
Take Phenergan exactly as prescribed.
--If you miss a dose...
If you are taking Phenergan on a regular schedule, take the forgotten dose as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Never take 2 doses at once.
--Storage instructions...
Tablets should be stored at room temperature, away from light. Suppositories should be stored in the refrigerator, in a tightly closed container.
What side effects may occur?
Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Phenergan.
• More common side effects may include:
Blurred vision, dizziness, drowsiness, dry mouth, increased or decreased blood pressure, nausea, rash, sedation, vomiting
Why should Phenergan not be prescribed?
Do not take Phenergan if you have ever had an allergic reaction to it or to related medications, such as Thorazine, Mellaril, Stelazine, or Prolixin. Phenergan is not for use in comatose patients, and should not be used to treat asthma or other breathing problems.
Special warnings about Phenergan
If you are taking other medications that cause sedation, your doctor may reduce the dosage of these medications or eliminate them while you are using Phenergan.
If you have a seizure disorder, Phenergan may cause your seizures to occur more often.
Phenergan can cause a serious--even fatal--decline in the breathing function. Avoid Phenergan if you have chronic breathing problems such as emphysema, or if you suffer from sleep apnea (periods during sleep when breathing stops).
Phenergan can also cause a potentially fatal condition called Neuroleptic Malignant Syndrome. Symptoms include high fever, rigid muscles, sweating, and a rapid or irregular heartbeat. If you develop these symptoms, stop taking Phenergan and see your doctor immediately.
Use Phenergan cautiously if you have heart disease, high blood pressure or circulatory problems, liver problems, the eye condition called narrow-angle glaucoma, peptic ulcer or other abdominal obstructions, or urinary bladder obstruction due to an enlarged prostate.
Phenergan may affect the results of pregnancy tests and can raise your blood sugar.
Some people have developed jaundice (yellow eyes and skin) while on Phenergan.
Tell your doctor if you have any uncontrolled movements or seem to be unusually sensitive to sunlight.
Remember that Phenergan can cause drowsiness.
Phenergan should not be given to children under 2 years of age, and should be used with caution in older children, due to the danger of impaired breathing. Large doses have been known to cause hallucinations, seizures, and sudden death, especially in children who are dehydrated. Drugs such as Phenergan are not recommended for the treatment of vomiting in children unless the problem is severe. Phenergan should also be avoided if the child has the serious neurological disease known as Reye's syndrome or any disease of the liver.
Possible food and drug interactions when taking Phenergan
Phenergan may increase the effects of alcohol. Do not drink alcohol, or at least substantially reduce the amount you drink, while taking Phenergan.
If Phenergan is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Phenergan with the following:

Certain antidepressant drugs, including Elavil and Tofranil
Drugs that control spasms, such as Cogentin
Drugs that reduce bone-marrow function (certain cancer drugs)
MAO inhibitors such as the antidepressants Nardil and Parnate
Narcotic pain relievers such as Demerol and Dilaudid
Sedatives such as Halcion, Dalmane, and Seconal
Tranquilizers such as Xanax and Valium
Special information if you are pregnant or breastfeeding
The effects of Phenergan during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, inform your doctor immediately. Although it is not known whether Phenergan appears in breast milk, there is a chance that it could cause a nursing infant serious harm. The use of Phenergan is not recommended during breastfeeding.
Recommended dosage
Phenergan is available in tablet, syrup, and suppository form. The suppositories are for rectal use only. Phenergan tablets and suppositories are not recommended for children under 2 years of age.
ALLERGY
Adults
The average oral dose is 25 milligrams taken before bed; however, your doctor may have you take 12.5 milligrams before meals and before bed.
Children
The usual dose is a single 25-milligram dose at bedtime, or 6.25 to 12.5 milligrams 3 times daily.
MOTION SICKNESS
Adults
The average adult dose is 25 milligrams taken twice daily. The first dose should be taken one-half to 1 hour before you plan to travel, and the second dose 8 to 12 hours later, if necessary. On travel days after that, the recommended dose is 25 milligrams when you get up and again before the evening meal.
Children
The usual dose of Phenergan tablets, syrup, or rectal suppositories is 12.5 to 25 milligrams taken twice a day.
NAUSEA AND VOMITING
The average dose of Phenergan for nausea and vomiting in children or adults is 25 milligrams. When oral medication cannot be tolerated, use the rectal suppository. Your doctor may have you take 12.5 to 25 milligrams every 4 to 6 hours, if necessary.
For nausea and vomiting in children, the dose is usually calculated at 0.5 milligram per pound of body weight and will also be based on the age of the child and the severity of the condition being treated. Phenergan and other anti-vomiting drugs should not be given to children if the cause of the problem is unknown.
INSOMNIA
Adults
The usual dose is 25 to 50 milligrams for nighttime sedation.
Children
The usual dose is 12.5 to 25 milligrams by tablets or rectal suppository at bedtime.
Older Adults
The dosage is usually reduced for people over 60.
Overdosage
Any medication taken in excess can have serious consequences. An overdose of Phenergan can be fatal. If you suspect an overdose, seek medical treatment immediately.
• Symptoms of Phenergan overdose may include:
Difficulty breathing, dry mouth, fixed and dilated pupils, flushing, heightened reflexes, loss of consciousness, muscle tension, poor coordination, seizures, slowdown in brain activity, slowed heartbeat, stomach and intestinal problems, very low blood pressure, writhing movements
Children may become overstimulated and have nightmares. Older adults may also become overstimulated.