• you are allergic to any ingredient in Phenergan
• you have severe central nervous system depression or are in a coma
• you are also taking astemizole, cisapride, terfenadine, or tramadol.

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

Some medical conditions may interact with Phenergan. 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 nervous system problems, bone marrow depression, heart problems, a blood disease, glaucoma, increased eye pressure, low blood pressure, liver problems, prostate problems, Parkinson disease, seizures, or Reye syndrome
• if you regularly consume large amounts of alcohol.

Some medicines may interact with Phenergan. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Charcoal or lithium because they may decrease Phenergan's effectiveness
• Angiotensin-converting enzyme (ACE) inhibitors (eg, enalapril), astemizole, cisapride, general anesthetics (eg, thiopental), methyldopa, terfenadine, or tramadol because side effects, such as low blood pressure and seizures, may occur
• ACE inhibitors (eg, enalapril), haloperidol, lithium, meperidine, metrizamide, monoamine oxidase inhibitors (MAOIs) (eg, phenelzine), naltrexone, polypeptide antibiotics (eg, actinomycin), or trazodone because the risk of their side effects may be increased by Phenergan
• Bromocriptine, epinephrine, levodopa, or pergolide because their effectiveness may be decreased by Phenergan.

This may not be a complete list of all interactions that may occur. Ask your health care provider if Phenergan 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.

Important safety information:

• Phenergan may cause drowsiness or dizziness. These effects may be worse if you take it with alcohol or certain medicines. Use Phenergan with caution. Do not drive or perform other possible unsafe tasks until you know how you react to it.
• Do not drink alcohol or use medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you are using Phenergan; it may add to their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.
• Neuroleptic malignant syndrome (NMS) is a possibly fatal syndrome that can be caused by Phenergan. Symptoms may include fever; stiff muscles; confusion; abnormal thinking; fast or irregular heartbeat; and sweating. Contact your doctor at once if you have any of these symptoms.
• Phenergan may cause you to become sunburned more easily. Avoid the sun, sunlamps, or tanning booths until you know how you react to Phenergan. Use a sunscreen or wear protective clothing if you must be outside for more than a short time.
• Use Phenergan with extreme caution in the elderly; they may be more sensitive to its effects.
• Phenergan should not be used in children younger 2 years. Serious, and sometimes fatal, side effects (difficult or slowed breathing, drowsiness leading to coma) have occurred when Phenergan has been used in children in this age group.
• Phenergan should be used with extreme caution in children 2 years old or older. The lowest effective dose should be used in children 2 years or older.
• Pregnancy and breast-feeding: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Phenergan while you are pregnant. Phenergan is found in breast milk. If you are or will be breast-feeding while you use Phenergan, check with your doctor. Discuss any possible risks to your baby.

Check with your doctor if any of these most common side effects persist or become bothersome:

Blurred vision; dizziness; drowsiness; dry mouth; nausea; vomiting.

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

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); confusion; excessive sweating; fainting; fever, chills, or sore throat; hallucinations; mental or mood changes (eg, agitation, delirium, exaggerated sense of well-being, excitability, hysteria, nervousness); seizures; severe or persistent dizziness; shortness of breath or trouble breathing; slow or fast heartbeat; tremor; trouble sleeping; uncontrolled muscle movements; unusual brusing or bleeding; yellowing of skin or eyes.

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.