What is promethazine 6.25 5ml used for?

Promethazine 6.25 5ml is an antihistamine medication that is used to treat a variety of conditions such as allergies, motion sickness, nausea and vomiting. It can also be used as a sedative and sleep aid. Promethazine comes in different strengths, with promethazine 6.25 mg/5mL being a common formulation. Here is a quick overview of what promethazine 6.25 5ml is used for:


Promethazine is an antihistamine, which means it blocks the effects of histamine in the body. Histamine is a chemical released by the immune system during an allergic reaction. This release of histamine is what causes allergy symptoms like itchy eyes, runny nose, sneezing, etc. By blocking histamine, promethazine provides relief from these annoying allergy symptoms. A dose of promethazine 6.25 5mL can help control allergy symptoms for 4 to 6 hours.

Motion Sickness

Motion sickness occurs when the brain receives conflicting signals about the body’s movement and position. Riding in a car, boat, plane or amusement park ride can trigger motion sickness. Promethazine helps prevent and treat motion sickness by reducing signaling confusion in the brain and vestibular system. A dose of promethazine 6.25 5mL about 30 minutes before traveling can help prevent motion sickness. It can also be used to stop motion sickness once it starts.

Nausea and Vomiting

Promethazine is commonly used to treat nausea and vomiting. It is very effective at controlling nausea and vomiting from various causes including:

  • Post-surgery
  • Anesthesia
  • Opioid pain medications
  • Chemotherapy
  • Motion sickness
  • Pregnancy morning sickness
  • Gastroenteritis (stomach flu)

A dose of promethazine 6.25 5mL can be given every 4-6 hours as needed to control severe nausea and vomiting. It works by blocking signaling from the brain’s nausea center.


Promethazine 6.25 5mL can be used as a mild sedative. The drowsiness side effect of promethazine makes it useful for treating insomnia and anxiety. It is sometimes given before surgery to induce sedation and reduce anxiety. Promethazine also potentiates the effects of opioid pain medications and sedatives. This allows lower dosages of these drugs to be used for sedation and anesthesia.

Allergic Reactions

In addition to controlling allergy symptoms, promethazine can also treat severe allergic reactions like anaphylaxis. It helps counteract dangerous histamine effects like lowered blood pressure, breathing difficulties, hives, and swelling. Promethazine should be given as soon as symptoms of a severe allergic reaction begin. It can be continued for 24-48 hours to prevent recurrence of symptoms.

Headache and Migraine

Promethazine may be used to enhance the pain-relieving effects of medications given for severe headache or migraine. It also provides sedation, which can help someone sleep off a severe migraine. However, promethazine should be used cautiously in migraine as it can sometimes trigger headache in sensitive individuals.

ICU Sedation

In the intensive care unit setting, promethazine may be used as an adjunct sedative. When combined with opioids like fentanyl, promethazine allows lower opioid doses to be used. This reduces the risks associated with opioids. Promethazine is especially helpful for sedation in patients with breathing problems as it has minimal effects on respiration.


Promethazine is a powerful antiemetic, meaning it prevents and treats nausea and vomiting. Here are some specific situations where promethazine is used as an antiemetic:

Post-surgery nausea and vomiting (PONV)

Many patients experience nausea and/or vomiting after having general anesthesia for surgery. Promethazine is highly effective at controlling PONV. It is superior to many other antiemetics in this setting.

Nausea and vomiting during pregnancy

Morning sickness and hyperemesis gravidarum (excessive vomiting) are common concerns during pregnancy. Promethazine is one of the preferred treatments for nausea and vomiting in pregnancy. However, other medications may be tried first.

Preventing motion sickness

Taking promethazine 30-60 minutes before travel can prevent motions sickness during travel by car, boat, plane, etc. It blocks signals in the brain that trigger nausea and vomiting.


Promethazine can reduce nausea and vomiting associated with viral gastroenteritis (“stomach flu”). Its antiemetic and sedative effects provide relief when oral rehydration is not tolerated.

Cancer chemotherapy

Nausea and vomiting are common side effects of chemotherapy medications. Promethazine is very effective at controlling chemotherapy-induced nausea and vomiting when combined with other antiemetic agents.


Promethazine’s strong sedative effects make it useful for treating insomnia. The drowsiness may help someone fall asleep. However, promethazine may cause excessive daytime sleepiness when used long-term for insomnia. It’s best for short-term use. Promethazine should not be combined with other sedatives when used for insomnia.


The calming effects of promethazine may help relieve symptoms of anxiety. It may be used alone or with other anti-anxiety medications. Similar to insomnia, promethazine is usually recommended for short-term anxiety relief only, due its sedating qualities.

ICU Agitation

Critically ill patients in the intensive care unit often experience agitation and anxiety. Promethazine can provide sedation and anti-anxiety effects for these patients without compromising their breathing. This makes it a useful ICU medication when opioid pain relievers are insufficient or inappropriate.


While it has no direct pain-relieving action, promethazine potentiates the effects of opioid medications. This synergistic effect allows lower doses of opioids to be used for pain control. However, promethazine should not be used solely for pain or as a substitute for opioid pain relievers.


Promethazine’s anticholinergic effects can help reduce dizziness caused by motion sickness or inner ear disturbances. Its antiemetic properties also reduce nausea and vomiting associated with some forms of dizziness.

Seasonal allergies

Seasonal allergic rhinitis (hay fever) results in runny nose, sneezing, watery eyes, and other symptoms. Promethazine blocks the histamine response responsible for many allergy symptoms. A single dose can provide relief for several hours. Some examples of when promethazine can help seasonal allergy symptoms:

  • During high pollen count days
  • Before mowing the lawn or yardwork
  • During camping or hiking trips
  • In combination with nasal steroids or antihistamines for severe symptoms

Insect Bites/Stings

Promethazine helps relieve itching and swelling from moderate insect bites and stings. It blocks the histamine response caused by the insect venom. Promethazine should not be used alone for severe reactions like anaphylaxis. Epinephrine, steroids, and other drugs may be needed along with promethazine.


Promethazine’s antihistamine effects can help relieve nausea, vomiting and dizziness associated with vertigo (spinning sensation). It also causes sedation which can minimize anxiety during vertigo episodes. However, promethazine should not be used long-term for vertigo. The underlying cause should be treated.

Alcohol Withdrawal

Promethazine has some mild benefits for treating alcohol withdrawal symptoms. Its sedative effects can help with anxiety and agitation associated with withdrawal. The antiemetic effects help with nausea and vomiting. However, promethazine is not sufficient as the sole medication for alcohol detoxification. Other drugs like benzodiazepines are considered first-line.

ICU Delirium

In critically ill patients, promethazine may be used to help prevent or treat delirium. It can provide sedation without compromising respiration like opioids can. By improving sleep and anxiety, promethazine reduces agitation and confusion in the ICU. However, other medications are usually preferred over promethazine for ICU delirium.


Rhinitis refers to inflammation of the nasal mucous membranes. Allergic rhinitis is caused by an allergic response. Non-allergic rhinitis results from irritants, chemicals, medications, hormonal changes etc. Promethazine can relieve symptoms of various types of rhinitis including:

  • Runny nose
  • Nasal congestion
  • Sneezing
  • Watery eyes
  • Post-nasal drip
  • Itchy nose, throat, eyes

Its antihistamine effects are useful for allergic rhinitis. The anticholinergic effects help dry up excess nasal secretions associated with non-allergic rhinitis.

Drug-Induced Parkinsonism

Sometimes antipsychotic drugs or other medications can cause symptoms of Parkinson’s disease like tremors, stiffness and movement problems. Promethazine may be used short-term to help control drug-induced parkinsonian symptoms until the causative medication can be changed.

Schizophrenia and Psychosis

Promethazine is sometimes used as an add-on treatment for schizophrenia when antipsychotics alone are insufficient. The sedative effects help control agitation, insomnia, and anxiety in schizophrenia. Promethazine may also be used for sedation in other psychotic disorders. However, it does not treat psychosis and should be used cautiously.

Opioid Potentiation

A major clinical use of promethazine is to potentiate or enhance the pain-relieving and sedative effects of opioid medications. This allows lower opioid doses be used. Some examples include:

  • Post-surgical pain control
  • Cancer pain
  • End-of-life care
  • Orthopedic procedures
  • Dental pain

Promethazine should only be used for opioid potentiation when monitored by a physician or in a healthcare facility. Risks include over-sedation and respiratory depression.


While promethazine is not a conventional treatment for ADHD, its sedating effects can help control hyperactivity and agitation in some cases. This may allow lower stimulant medication doses to be used. However, promethazine should be used cautiously in ADHD due its addiction potential.

Sleep Aid

The strong sedative properties of promethazine make it useful as a short-term sleep aid. It can help induce sleep in people having trouble falling asleep. However, promethazine may cause excessive daytime drowsiness, especially with repeated doses. It should not be combined with other sedatives.


Promethazine has some anticholinergic effects which reduce body secretions and smooth muscle contractions. This provides additional benefits in some conditions such as:

  • Drying up excess nasal secretions associated with allergies and colds.
  • Slowing intestinal mobility to reduce nausea/vomiting.
  • Preventing motion sickness by drying secretions in the inner ear.
  • Reducing bronchial secretions to help breathing in asthma and COPD.

However, promethazine should be avoided in patients with glaucoma, urinary retention issues, constipation, and other conditions exacerbated by anticholinergics.

Sedative and Hypnotic

In addition to allergy treatment, promethazine is widely used for its sedative and hypnotic (sleep-inducing) properties. It works as a central nervous system depressant. Promethazine is helpful for sedation in situations like:

  • Pre-operative and post-operative sedation
  • Sedation during procedures or treatments
  • Insomnia
  • Anxiety or agitation requiring sedation
  • Potentiation of opioid analgesics
  • Alcohol withdrawal

Promethazine as a sedative or hypnotic should be used short-term only. It may cause prolonged drowsiness. Combining with alcohol or other sedatives increases risks.

Pre-operative Sedation

Promethazine is commonly given before surgeries and procedures along with opioid pain medications. It potentiates the sedative effects, allowing lower opioid doses be used. Pre-operative promethazine also provides the following benefits:

  • Reduces anxiety before surgery
  • Helps induce sleep if surgery is early morning
  • Causes amnesia so less medication is needed during surgery
  • Dries secretions to reduce risk of aspiration during anesthesia
  • Has antiemetic effect to prevent PONV after surgery

Risks of excessive sedation and slowed breathing need to be monitored when promethazine is used as a pre-operative sedative.

ICU Agitation and Delirium

In the ICU, critically ill patients often experience agitation, anxiety and delirium. Promethazine provides sedation and anti-anxiety effects without compromising breathing like opioids can. This makes it useful for safely managing agitated, delirious ICU patients. However, promethazine should be used cautiously and only for short periods.


In summary, promethazine 6.25 5mL is a medication that has many uses thanks to its antihistamine, antiemetic, sedative and anticholinergic properties. It can provide relief from allergy symptoms, nausea, vomiting, insomnia, anxiety and more. However, side effects like prolonged sedation and anticholinergic effects need to be considered. Promethazine is especially beneficial when combined with opioids and for pre-operative sedation. When used appropriately under medical supervision, promethazine can safely treat multiple conditions.

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