Promethazine (Promethegan) is a rectal suppository. It's used to treat different conditions in adults and children, such as allergy symptoms and motion sickness. It can also help with nausea and vomiting from certain procedures. Promethazine (Promethegan) works by blocking several chemicals, including histamine, dopamine, and acetylcholine. This medication is inserted into the rectum, multiple times a day as needed. Promethazine (Promethegan) suppository is an alternative option to the promethazine tablets for people who can't take medications by mouth. Common side effects include drowsiness and dizziness. This medication is available as both brand-name and generic versions.
Runny nose, watery eyes, and other symptoms of allergies
Runny or stuffy nose that isn't caused by allergies
Rash, swelling, anaphylaxis, and other symptoms of an allergic reaction
Treatment or prevention of nausea and vomiting before and after surgery
Treatment or prevention of motion sickness
Treatment of pain along with other pain medications after surgery
Help to relax your body and produce a light sleep, particularly before a procedure
Promethazine (Promethegan) is an antihistamine and an anticholinergic medication. It also blocks a chemical called dopamine.
When promethazine (Promethegan) blocks histamine, it relieves symptoms of allergy, such as rash, watery eyes, and runny nose. It can also cause you to feel drowsy and calm before a surgery.
When promethazine (Promethegan) blocks acetylcholine and dopamine, it helps to relieve symptoms of nausea, vomiting, and motion sickness.
Source: DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Stop taking this medicine and get emergency help immediately if any of the following effects occur:
Rare
Symptoms of neuroleptic malignant syndrome; two or more occur together; most of these effects do not require emergency medical attention if they occur alone
Convulsions (seizures)
difficult or unusually fast breathing
fast heartbeat or irregular pulse
high fever
high or low (irregular) blood pressure
increased sweating
loss of bladder control
severe muscle stiffness
unusually pale skin
unusual tiredness or weakness
Incidence not known
Abdominal or stomach pain
black, tarry stools
bleeding gums
blood in urine or stools
bloody nose
blurred vision
chest pain or discomfort
chills
clay-colored stools
confusion as to time, place, or person
cough or hoarseness
dark urine
decreased awareness or responsiveness
difficulty or troubled breathing
double vision
fast, pounding, or irregular heartbeat or pulse
fever with or without chills
fixed position of eye
headache
heavier menstrual periods
high fever
holding false beliefs that cannot be changed by fact
hyperexcitability
increased or decreased blood pressure
increased sweating
irregular, fast or slow, or shallow breathing
large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
lightheadedness, dizziness, or fainting
loss of appetite
loss of bladder control
lower back or side pain
mimicry of speech or movements
mutism
nasal stuffiness
negativism
nightmares
noisy breathing
not breathing
painful or difficult urination
pale or blue lips, fingernails, or skin
peculiar postures or movements, mannerisms or grimacing
pinpoint red spots on skin
seeing double
seeing, hearing, or feeling things that are not there
seizures
severe muscle stiffness
severe sleepiness
shortness of breath
skin rash
slow or irregular heartbeat
sores, ulcers, or white spots on lips or in mouth
sticking out of tongue
swollen glands
tightness in chest
uncontrolled twisting movements of neck
unpleasant breath odor
unusual bleeding or bruising
unusual excitement, nervousness, or restlessness
unusual tiredness or weakness
vomiting of blood
yellow eyes or skin
Symptoms of overdose
Discouragement
dizziness, faintness, or lightheadedness when getting up from a lying or sitting position suddenly
excessive muscle tone
feeling of warmth
feeling sad or empty
irritability
lack of appetite
loss of interest or pleasure
muscle tension or tightness
overactive reflexes
pupils of eyes large and not moving or responding to light
redness of the face, neck, arms and occasionally, upper chest
shakiness and unsteady walk
sudden death
trouble concentrating
trouble sleeping
unconsciousness
unsteadiness, trembling, or other problems with muscle control or coordination
unusual paleness
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Incidence not known
blistering, crusting, irritation, itching, or reddening of skin
continuing ringing or buzzing or other unexplained noise in ears
cracked, dry, scaly skin
dizziness
drowsiness
excitation
false or unusual sense of well-being
hearing loss
hives or welts
increased sensitivity of skin to sunlight
lack of coordination
loss of strength or energy
muscle pain or weakness
redness or other discoloration of skin
relaxed and calm
sunburn
swelling
unable to sleep
vomiting
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Good option for people who have trouble swallowing pills or taking injections
Can be used in people 2 years and older
Available in multiple strengths
Before using promethazine (Promethegan), it's best to have a bowel movement. Also, wash your hands well with soap and water.
Unwrap the promethazine (Promethegan) suppository before using it. To make it easier to insert the promethazine (Promethegan) suppository, you can lubricate the tip.
When you're ready to insert promethazine (Promethegan) suppository, lie on your side and bend your upper leg towards your stomach. Lift your buttock and use your finger to insert the suppository with the tip going in first. Hold your buttocks together for a few seconds afterwards.
Talk to your primary care provider first before using promethazine (Promethegan) if you're taking or have recently taken medications for Parkinson's disease or depression that are known as monoamine oxidase inhibitors (MAOIs). These medications can sometimes interact with promethazine (Promethegan) and cause uncontrollable body movements.
Promethazine (Promethegan) can cause you to sunburn more easily. To lower your risk, make sure to limit or avoid sun exposure during treatment with promethazine (Promethegan). Wear sunscreen and protective clothing when outside, even on overcast days.
Promethazine (Promethegan) can cause dizziness or drowsiness. Don't drive a car or perform dangerous activities until you know how promethazine (Promethegan) affects you. Avoid taking promethazine (Promethegan) with alcohol since this combination can slow down your brain activity, which might lead to slow breathing and excessive sleepiness.
Promethazine (Promethegan) can affect the results of certain lab tests, such as glucose or pregnancy tests. Talk with your prescriber if you have concerns about the results of any lab tests while using this medication.
Store promethazine (Promethegan) in the refrigerator and only take it out when you're ready to use it. Put the package back in the refrigerator after removing your dose to prevent the suppositories from melting.
Promethazine (Promethegan) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Children under 2 years old | History of breathing problems (e.g., sleep apnea, asthma) | Taking other medications that slow down breathing
In rare cases, promethazine (Promethegan) can significantly slow down breathing, which can be life-threatening. The risk is higher for children under 2 years old, people with a history of breathing problems, or if you're taking other medications that can cause breathing problems. For this reason, promethazine (Promethegan) isn't recommended for children if they're under the age of 2. If you regularly take medications that can slow your breathing, discuss alternatives with your healthcare team as there might be safer options to treat your condition. If you notice you or your child has slow and shallow breathing, get medical attention right away.
Risk factors: Drinking alcohol | Taking other medications that cause drowsiness
Promethazine (Promethegan) can make you feel very sleepy and affect your ability to think. The risk is higher if you drink alcohol or if you take medications that make you drowsy, such as opioids, sleep medications, or certain antidepressants. Don't drive a car or operate machinery right after using this medication. If you experience symptoms such as slurred speech, lightheadedness, confusion, dizziness, or excessive drowsiness, get medical attention right away.
Risk factors: Glaucoma | Heart problems | Enlarged prostate | Breathing problems | Bladder problems | Stomach ulcer | Liver problems
Before taking promethazine (Promethegan), be sure to discuss all of your medical conditions with your primary care provider. Promethazine (Promethegan) can make certain problems worse.
Risk factors: Taking medications that make seizures more likely | History of seizures
Promethazine (Promethegan) can cause people with a history of seizures to have more frequent episodes. Promethazine (Promethegan) can also raise the risk of seizures in people who take medications that lower seizure threshold, such as tramadol (Ultram). If you have one of the risk factors, talk to your prescriber before using promethazine (Promethegan). Get medical attention right away if you have symptoms such as uncontrolled body movements, repeated eye blinking, tingling in your body, blurry vision, or feeling confused.
Risk factor: Taking anticancer medications
In some rare cases, promethazine (Promethegan) can lower your white blood cell (WBC) count. This is more likely to happen if you are going through chemotherapy or other anticancer treatments. WBCs are responsible for fighting infections in your body. Low levels of WBC can cause you to get sick more easily. Let a member of your healthcare team know if you have symptoms of an infection, such as fever, chills, or cough, and they'll let you know if you need more medical attention.
Risk factor: Taking antipsychotic medications
Promethazine (Promethegan) can cause a rare, but serious, medical condition called neuroleptic malignant syndrome (NMS). This condition happens when dopamine (a chemical in your body) is not transported correctly in the brain. Certain medications, such as antipsychotics, can raise your risk of NMS. If you take medications for mental health, please talk with your prescriber before taking promethazine (Promethegan). Please get medical attention right away if you notice signs and symptoms such as high fever, fast heartbeat, rapid breathing, stiff muscles, excessive sweating, or confusion. Don't use promethazine (Promethegan) if you have a history of NMS.
Risk factors: Children who are sick and dehydrated | Taking an MAOI
Promethazine (Promethegan) can cause involuntary muscle movements including sticking out your tongue and twisting your neck. This risk is higher if you're taking MAOIs or if the medication is given to children who are sick and dehydrated (low fluids in the body). Notify your or your child's pediatrician right away if any of these symptoms develop while using promethazine (Promethegan).
Allergy symptoms
Adults and children 2 years and older: The typical dose is 25 mg inserted rectally once daily at bedtime. An alternative dosing is 6.25 mg to 12.5 mg up to three times daily.
Motion sickness
Adults: The typical dose is 25 mg inserted rectally 2 times daily. Take your first dose 30 to 60 minutes before you travel, and take the second dose 8 to 12 hours later if needed.
Children 2 years and older: The typical dose is 12.5 mg to 25 mg inserted rectally 2 times daily.
Nausea and vomiting
Adults: The typical dose is 12.5 mg to 25 mg inserted rectally every 4 to 6 hours as needed.
Children 2 years and older: Your child's pediatrician will determine the dose for your child based on their body weight. The typical dose is 0.5 mg/lb of body weight inserted rectally every 4-6 hours as needed.
"Light" sleep before or during a procedure
Adults: The typical dose is 25 mg to 50 mg inserted rectally once at bedtime the night before the procedure.
Children 2 years and older: The typical dose is 12.5 mg to 25 mg inserted rectally once at bedtime the night before the procedure.
Pain relief before and after surgery
Adults: Before surgery, the typical dose is 50 mg inserted rectally and used in combination with other pain medication(s). After surgery, the typical dose is 25 mg to 50 mg taken together with other pain medication(s).
Children 2 years and older: Your child's pediatrician will determine the dose for your child based on their body weight. The typical dose before surgery is 0.5 mg/lb of body weight, in combination with other pain medication(s). The typical dose after surgery is 12.5 mg to 25 mg inserted rectally and taken together with other pain medication(s).
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Children younger than 2 years old
People in a coma
Treatment of lower respiratory tract problems, such as asthma
Allergic to phenothiazines
Runny nose, watery eyes, and other symptoms of allergies
Runny or stuffy nose that isn't caused by allergies
Rash, swelling, anaphylaxis, and other symptoms of an allergic reaction
Treatment or prevention of nausea and vomiting before and after surgery
Treatment or prevention of motion sickness
Treatment of pain along with other pain medications after surgery
Help to relax your body and produce a light sleep, particularly before a procedure
Allergies
Common cold symptoms
Trouble sleeping for people 12 years and older
Prevention of nausea and vomiting due to cancer medications (chemotherapy) or radiation therapy
Prevention of nausea and vomiting after surgery
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Committee on Obstetric Practice. (2018). Nausea and vomiting of pregnancy. American College of Obstetricians and Gynecologists Practice Bulletin.
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D’Souza, R. S., et al. (2023). Extrapyramidal symptoms. StatPearls.
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