Promethazine and Codeine (Oral)

Promethazine and codeine is a combination of medicines that are used together to treat and relieve the symptoms of common colds and allergies, including coughing, sneezing, and a runny or blocked nose. In certain cases, this medication is also used to help treat certain breathing illnesses such as sinusitis or bronchitis.


Also known by its brand name Phenergan wCodeine, promethazine and codeine is a combination of medications that are used to help relieve patients from the effects of allergies and common cold symptoms. These symptoms can include sneezing, coughing and a runny or blocked nose. Alongside this, promethazine and codeine is also used in helping to treat bronchial or sinus illnesses such as sinusitis or bronchitis in certain patients.

Classed as a phenothiazine, the medicine promethazine tends to be used mostly as an antihistamine, sedative, an anti-nausea medicine or as a cough suppressant. This is different to most other forms of phenothiazines, such as chlorpromazine or trifluoperazine, which are predominantly used as antipsychotics to help treat mental illnesses.

Promethazine acts by inhibiting the effects of a substance that is naturally produced within the body, known as histamine. Histamine is produced as the result of an allergic reaction and can create unpleasant problems and irritations to the eyes, nose and throat. In certain cases, histamine can prove to be more harmful to some people, having the potential to cause the air passages of the lungs to narrow and close up, consequently making breathing hard. Because of its anti-histamine properties, promethazine is very effective at reducing any symptoms brought on by allergies.

Codeine offers an element of pain relief to this medicine combination, making it effective in the reduction and treatment of the symptoms from illnesses such as the flu, common colds, bronchitis and sinusitis. Classed as a narcotic analgesic that is ideal for treating moderate to severe pain, it works by triggering the central nervous system to relieve pain. It does this by attaching receptors on nerves in the brain that will increase the pain threshold as well as reduce the recognition of pain. Alongside this, codeine is a known cough suppressant and can reduce a patient's need to cough. This makes it particularly effective at treating a number of throat, chest or lung conditions.

When used together, promethazine and codeine is an effective treatment for patients who are suffering from particular allergy discomfort, or breathing illnesses that affect the airways and cause coughing. Offering the relief of a range of symptoms from sneezing to watery eyes and irritated throats, this medication is able to help patients cope with common allergic reactions, the flu and colds.

Promethazine and codeine can be used in adults and pediatric patients who are older than six years of age. For children younger than six years, an alternative medication will be prescribed as it has not shown safety or effectiveness in this age range. It is taken orally in a syrup dosage form and must always be prescribed by a doctor.

Conditions Treated

Type Of Medicine

  • Narcotic analgesic
  • Cough suppressant
  • Phenothiazine
  • Antihistamine

Side Effects

It is important that all patients taking this medication are aware of the potential side effects that it can cause before beginning their treatment. This is because side effects should be monitored closely to avoid them from progressing to more serious illnesses. Your doctor will also be able to adjust or alter your treatment to help minimise and manage any side effects that you may be experiencing.

Most of the side effects of promethazine and codeine are uncommon. In some cases, they will not require medical attention and will go away once your body has become adjusted to the medication. However, if any of these effects remain persistent or cause concern, make sure to discuss them with your doctor.

Side effects that may not need medical treatment include:

  • Unpleasant dreams
  • Blurred, a loss of, or double vision
  • Hearing loss, ringing or buzzing noises in the ears
  • A change in color perception
  • Drowsiness
  • Feeling more tired than usual
  • Difficulty in sleeping
  • An unusual sense of well-being
  • An increased sensitivity of the skin to sunlight
  • Night blindness
  • Nausea
  • An overbright appearance of lights
  • Redness of the skin
  • Feeling relaxed and calm
  • Abnormal excitement, nervousness, or restlessness

The long-term use of this medication can also cause severe constipation. This is a more common side effect from using narcotics for elongated periods of time. To avoid this from happening, it is highly likely that your doctor will instruct you to drink plenty of fluids, increase your fiber intake and in some cases, take laxatives. Make sure that you follow your doctor's orders carefully, as if constipation perseveres, it can cause more harmful health problems.

It is also important that patients are aware that codeine becomes morphine once it is in the body. Although it's a rare occurrence, some patients are able to transform codeine into morphine at a much faster rate than others. Patients who do this are known as ultra-rapid metabolizers of codeineĀ. Because of this, it is essential that patients closely monitor the side effects of extreme sleepiness, confusion or shallow breathing. Any patients who may be experiencing the above side effects are likely to have too much morphine in their body due to this ultra-rapid metabolizing and will experience more side effects than usual. This is something that should be mainly monitored in pediatric patients as they are most susceptible.

As with all medication, promethazine and codeine has the potential to cause some serious side effects. If you experience any of the following side effects whilst taking this medication, please contact your doctor immediately. This will ensure that you are able to manage and treat more serious side effects with ease.

Contact your doctor straight away if you experience any of the following side effects:

  • Stomach or abdominal pain
  • Chills or cold sweats
  • Clay-colored stools
  • Coughing
  • Dark urine
  • A decrease in the frequency or volume of urination
  • Painful or difficult urination
  • Diarrhea
  • Dizziness
  • Fever
  • Headache
  • Hives or welts
  • Itching or a rash
  • Any hive-like swelling of the face, mouth, throat, hands, legs or sex organs
  • Loss of appetite
  • Nausea
  • Noisy breathing
  • Rectal bleeding
  • Redness of the face, neck, arms, and occasionally, upper chest
  • Shakiness in the legs, arms, or hands
  • Shortness of breath
  • Sweating
  • Tightness in the chest
  • Trembling of the hands or feet
  • An unusual or unpleasant breath odor
  • Blood in vomit
  • Yellowing eyes or skin

If you experience convulsions, any difficulty in breathing, a fast heartbeat, high fever, high or low blood pressure and severe muscle stiffness, make sure to alert a healthcare professional immediately. Alongside other symptoms including increased sweating, loss of bladder control, unusually pale skin and tiredness, these are all indicators of a severe condition known as neuroleptic malignant syndrome (NMS).

In addition to this, it is essential that patients are aware of the signs of an overdose. These can include cold, clammy skin, an irregular heartbeat, a weak pulse or no blood pressure, shallow breathing, pale or blue lips, fingernails, or skin and vomiting. If you suspect that you or your child have taken an overdose of promethazine and codeine, make sure to seek emergency medical attention at once.


Your dose of promethazine and codeine will be dependant on a number of factors including any current health conditions that you may have and any other medications that you may be taking. Also, the amount that you will take will be based on the strength of the medicine, the number of daily doses you will take, the time allowed between doses and the duration that you will be taking it for.

The standard dose of promethazine and codeine for adults and children ages 12 years and older is 5 ml, or one teaspoon, every four to six hours. Patients should not take more than 30 ml in a 24 hour period.

In child patients of six to 11 years old, the standard dose is 2.5 to 5 ml, or half to one teaspoonful, every four to six hours. This dose should never exceed 30 ml in a 24 hour period.

For child patients under the age of six years old, this medicine is not recommended. Your doctor will find an alternative treatment instead.

The above doses are common but are not applicable to everyone. If your doctor decides on a different dosing plan, make sure to follow their instructions exactly. Once your dose has been decided, it is important to be aware that when taken regularly for a long period, this medicine is habit-forming and can result in mental or physical dependence. Because of this, it is important that you take this medication exactly as directed by your doctor and do not stop or continue your treatment for any duration other than as directed.

Measuring the oral liquid with a medical measuring spoon, oral syringe or cup will also ensure that the correct dose is given each time, helping to avoid side effects or dependency.

In all cases with this medicine's dosage, it is important to never double dose if you have missed a day's dose. Instead, if you have missed a dose you should skip the missed dose and return to your regular dosing schedule.


Before taking this medication, it is vital that your doctor is aware of any other prescription or over-the-counter medications that you may be taking. This is because drug interactions can alter the effectiveness of your medication and can also increase your risk of experiencing serious side effects. There are a total of 292 severe drug interactions that this medication can have, so it is essential that you are as transparent as possible with your doctor.

Some of the most common medications that can cause interactions include:

  • Advair Diskus (fluticasone / salmeterol)
  • Aspirin Low Strength (aspirin)
  • Cymbalta (duloxetine)
  • Flonase (fluticasone nasal)
  • Lipitor (atorvastatin)
  • Nexium (esomeprazole)
  • ProAir HFA (albuterol)
  • Singulair (montelukast)
  • Symbicort (budesonide / formoterol)
  • Ventolin HFA (albuterol)
  • Xanax (alprazolam)
  • Zyrtec (cetirizine)

The potential to have more harmful side effects such as severe drowsiness, slow or shallow breathing and dizziness may be exacerbated if promethazine and codeine is combined with other medicines that can cause drowsiness or breathing problems. If you are also taking any opioid pain medicines or opioid cough relievers including morphine or hydrocodone or any medicines for sleep or anxiety such as alprazolam or zolpidem, make sure to tell your doctor. In addition to this, muscle relaxants including carisoprodol or cyclobenzaprine and other antihistamines including cetirizine and diphenhydramine should be discussed. In particular, it is important to alert your doctor of any antihistamines that are applied topically (to the skin). This includes diphenhydramine cream, ointment or spray, cimetidine, metoclopramide and naltrexone.

It is possible for other medications to affect the disposal of promethazine and codeine from your body, which in turn, may cause harmful reactions and cause the medication to be less effective. In particular, any azole antifungals including ketoconazole, bupropion and fluoxetine, and macrolide antibiotics such as erythromycin need to be alerted to your doctor. Additionally, HIV medications such as ritonavir and paroxetine, rifamycins and specific drugs used to treat seizures should be discussed with your doctor.

Promethazine and codeine also has the potential to interfere with specific laboratory tests, in particular pregnancy, blood sugar and amylase/lipase level tests. In rare cases, it can cause false test outcomes. For this reason, it is vital that any laboratory professionals and your doctors are all aware that you are using this drug before any tests are taken.

In addition to prescribed and over-the-counter medications, it is important that your doctor knows of any vitamins or herbal supplements you may be taking. Vitamin B12, Vitamin D3 and fish oil, are known to interact with this medication and should be discussed with a healthcare professional.

Your doctor will also want to know of any dietary or lifestyle factors that may affect the success of your treatment. Alcohol and marijuana are of particular importance as they can exacerbate the certain side effects such as drowsiness.


Before beginning your treatment with promethazine and codeine, your doctor needs to be aware of any medical conditions that you may have, as some can seriously affect how this medication works.

If you have any of the following conditions, make sure to tell your doctor:

Promethazine and codeine can cause some people to experience dizziness, drowsiness or feel less alert than they may normally be. Because of this, it is important that patients avoid driving, operating machinery or doing any activities that could be dangerous if you are unalert. It is also possible that standing up suddenly from a seated or lying position will cause lightheadedness, and therefore you should stand up slowly.

As this medication can cause people to feel less alert, tired or dizzy, it can increase the effects of alcohol and other central nervous system depressants. If you are consuming other antihistamines, sedatives, tranquilizers, sleep aids, narcotics or seizure medication, make sure to discuss it with a doctor before taking it alongside this medication. It is also important to remember that anesthetics and some dental anesthetics can cause the same reactions, and should be discussed with a doctor or dentist before being taken.

Patients may also notice that this medication can cause the skin to become more sensitive to sunlight. Because of this, you should avoid sunlamps and tanning booths and use the appropriate sunscreen when you are outside.

For patients who are breastfeeding, if you are an ultra-rapid metabolizer of codeine, there is a possibility that the medication can be transferred to your nursing baby through your breastmilk. This can cause a morphine overdose to your infant and must be avoided. If you become extremely tired and experience any difficulty in caring for your baby, contact your doctor when possible. Your baby should be sleeping for no more than four hours at a time and nursing every two to three hours. If you notice that your baby shows any signs of increased sleepiness, difficulty breathing, limpness or is struggling to breastfeed, go to an emergency room immediately. These can all be signs of an overdose and require immediate treatment. Before taking this medication, make sure to discuss any questions or concerns that you may have about its effects on your infant, with your doctor.


This medicine should be safely stored out of the reach of children, pets and vulnerable adults. It should be kept at room temperature, away from direct heat, moisture, and light. Do not freeze this medication.

You should also dispose of your medicine once you have finished your treatment, if it reaches its expiry date, or if it appears to be damaged.


Promethazine and codeine is an effective and easy treatment for patients who suffer from allergies or who may be experiencing a common cold, flu or illnesses that cause coughing or may affect breathing. Working to alleviate the symptoms that these conditions create, the medication combines two drugs together to provide patients with a way to reduce discomfort and speed up recovery.

Although in most cases they are not serious, symptoms of allergies tend to be unpleasant and can cause an impact on many people's daily routine. They can include eye irritation, sneezing, a runny or blocked nose, coughing and a sore or irritated throat.

Whilst promethazine acts as an antihistamine, reducing and inhibiting allergy symptoms, codeine acts as a cough suppressant and pain reliever, making it ideal for patients who suffer from breathing illnesses. This is also why promethazine and codeine is also used to help treat certain conditions that may affect the throat, chest or lungs such as sinusitis or bronchitis.

To experience the most positive results and the lowest chance of experiencing side effects, this medication requires a commitment and responsibility to a regular dosing schedule which can be daunting to some. It is essential that patients take their instructed dose exactly as prescribed by their doctor. Double dosing or continuing the administration of this medication after your finish date must be avoided. This is because when taken for extended periods of time, this medication can become habit forming and patients may become physically or mentally dependant on it. If you are a patient who has suffered from an addiction in the past, it is important that you discuss it with your doctor before beginning your treatment. For guidance on your dosing schedule, food or drink interactions and on advice for your medication management, talk to your doctor or pharmacist who will be able to provide you with useful information and tips.

Throughout your treatment with promethazine and codeine, it is vital that you monitor any side effects and reactions that you may be having. Although serious side effects tend to be rare, they can require immediate medical attention and can be harmful to your health. The most common effects tend to include constipation, drowsiness and feeling tired. For this reason, it is important that patients do not consume alcohol or other central nervous system depressants alongside this medication, as these can exacerbate certain side effects.

Additionally, it is normal for patients to experience a dry mouth when taking this medication. This can be relieved through the use of gum, sucking on ice or using a substitute for saliva. If your mouth is persistently dry for more than two weeks, you should talk to a doctor or dentist as to avoid any dental problems.

You will also be expected to be transparent about any other medicines that you may be taking, and you should tell dentists, doctors or laboratory professionals that you are taking this medicine. Due to its ability to interact with other medications and medical tests, it is important that you inform professionals before having blood, pregnancy and other medical tests to avoid false results.