Phenerzine

Promethazine is a prescription medication used to treat allergic reactions and nausea. Promethazine belongs to a group of drugs called antihistamines. It blocks the effect of histamine, a chemical in the body that causes symptoms of allergic reactions. Promethazine also belongs to another group of drugs called antiemetics, which reduce feelings of nausea.

Promethazine comes as a tablet, oral solution (liquid), rectal suppository, and a liquid to be injected into a muscle.  It is usually taken once daily at bedtime or before meals every six to twelve hours as needed to relieve symptoms of allergy or nausea. 

Promethazine is a prescription medication used to treat symptoms of allergic reactions, such as:

• rhinitis (sneezing, stuffy or runny nose)
• itchy & watery eyes
• skin irritation, such as swelling or hives

Promethazine is also used for:

• prevention or treatment of nausea & vomiting, including nausea & vomiting after surgery
• prevention or treatment of motion sickness
• sedation (to calm or encourage light sleeping)

Take promethazine exactly as prescribed by your doctor. Follow the directions on your prescription label carefully. Your doctor will determine the best dose for you based on your age and weight (particularly for children), the medical condition being treated, other medications you are taking, and other medical conditions you may have.

Allergies

The recommended dose of promethazine for treating allergies in most people is 25 mg before bedtime.

Nausea and Vomiting

For the treatment of nausea and vomiting, the recommended dose is 12.5 to 25 mg, taken every four to six hours, as needed.

Morning Sickness

The recommended dose for the treatment of morning sickness is 25 mg twice daily.

Promethazine for Children

Dosing for children is determined by weight.

Sedation (to calm or encourage light sleeping)

Adults usually require 25 to 50 mg for nighttime, presurgical, or obstetrical sedation. The recommended oral or rectal suppository dose to provide sedation in children is 12.5 to 25 mg at bedtime.

Promethazine should not be used in pediatric patients less than 2 years of age because of the potential for fatal respiratory depression. Postmarketing cases of respiratory depression, including fatalities, have been reported with use of promethazine in pediatric patients less than 2 years of age. Caution should be exercised when administering Promethazine to pediatric patients 2 years of age and older.

Promethazine Injection can cause severe chemical irritation and damage to tissues regardless of the route of administration. Irritation and damage can result from perivascular extravasation, unintentional intra-arterial injection, and intraneuronal or perineuronal infiltration. Adverse reactions include burning, pain, thrombophlebitis, tissue necrosis, and gangrene. In some cases, surgical intervention, including fasciotomy, skin graft, and/or amputation have been required.

Due to the risks of intravenous injection, the preferred route of administration of Promethazine Injection is deep intramuscular injection. Subcutaneous injection is contraindicated

Serious side effects have been reported with promethazine including:

• Promethazine should not be used in children under two years of age because it can cause breathing difficulties leading to death. Caution should also be used when giving promethazine to children 2 years of age and older.
• severe tissue damage especially when injected directly into a vein (IV). Tell your healthcare provider right away if you have some or all of the following symptoms:
• burning or pain
• redness
• swelling
• loss of sensation
• paralysis
• blackened/dead tissue

Promethazine can cause drowsiness.  Do not drive or operate heavy machinery until you know how promethazine affects you.

Serious side effects have been reported with promethazine.  See "Drug Precautions" section.

• dizzness
• drowsiness
• blurred vision
• confusion
• dry mouth

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.  Especially tell your doctor if you take:

• medications that cause drowsiness such as:
  • alcohol
  • medications for anxiety
  • sedatives/hypnotics including barbiturates such as phenobarbital (Luminal) and sleeping pills
  • narcotics such as hydrocodone or codeine
  • tricyclic antidepressants such as amitriptyline, doxepin, and nortriptyline
• epinephrine (Epipen)
• monoamine oxidase inhibitors (MAOIs) such as isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), and selegiline (Eldepryl, Emsam, Zelapar)

Tell your doctor if you are pregnant or plan to become pregnant.

Tell your doctor if you are breastfeeding or plan to breastfeed.  It is not known if promethazine is excreted in human breast milk or if it will harm your nursing baby.

Promethazine should not be used in children under two years of age because it can cause breathing difficulties leading to death.

Promethazine can cause dizziness and drowsiness.  Do not drive or operate heavy machinery until you know how promethazine affects you.

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.  Especially tell your doctor if you take medications that cause drowsiness.