How do codeine and morphine differ


This is how codeine works

Coughing is a healthy defense reaction in the body. It helps to remove foreign bodies from the airways. Bacteria, viruses or, for example, smoke particles are coughed up together with some mucus. The impulse for this is provided by the cough center in the brain stem, to which the irritation of the mucous membrane is reported via nerve tracts.

If the mucous membrane is irritated or inflamed, the urge to cough can also arise if there is no secretion in the airways. One then speaks of the "dry, irritating cough". This annoying cough therefore has no physiological benefit.

The active ingredient dampens the cough reflex by inhibiting the cough center in the brain stem. Morphine, to which codeine is converted in the liver in small quantities, is mainly responsible for the effect of codeine.

The pain-relieving (analgesic) effect is also based mainly on the metabolic intermediate product morphine. Codeine itself can also dock to opioid receptors, but with less ability to bind.

Uptake, breakdown and excretion of codeine

The active ingredient is taken by mouth (orally) as codeine drops or in cough syrup. It is quickly absorbed from the small intestine and absorbed into the blood. Therefore, after taking it on an empty stomach, maximum drug levels are reached after about an hour. In the liver, the active ingredient is broken down into intermediate products (including morphine) and then excreted in the urine via the kidneys.

When is codeine used?

Codeine is mainly used to treat dry, dry coughs. In combination with paracetamol, the active ingredient is also used as a pain reliever.

This is how codeine is used

In the case of a dry cough, the codeine dosage is adjusted to the patient's cough frequency and strength. Adults and adolescents over twelve years of age without other severe respiratory diseases may consume a maximum of 200 milligrams of the active ingredient per day. The daily dose is usually divided into four divided doses. The last dose should preferably be taken shortly before going to bed in order to avoid sleep disturbances caused by the urge to cough.

What are the side effects of codeine?

Very common codeine side effects affect the gastrointestinal tract and can manifest themselves as nausea, vomiting and, especially at the beginning of therapy, as constipation.

Mild headaches and drowsiness are also common.

Occasionally, it comes to sleep disturbances, shortness of breath or dry mouth.

Severe allergic reactions (such as Stevens-Johnson syndrome) are rarely possible side effects of codeine.


If the doses are too high or in people who convert the active ingredient to morphine particularly quickly due to genetic conditions, symptoms of opiate poisoning can arise. These include euphoria or increased sleepiness, decreased respiratory drive (respiratory depression), drop in blood pressure, disorders of voluntary movement sequences (ataxia) and muscle cramps. The codeine / alcohol mixture can exacerbate the symptoms of an overdose.

If, after using codeine, you suffer from the above-mentioned severe side effects or symptoms that have not occurred before, please consult your doctor.

When should you not take codeine?

Codeine is not allowed to take anyone who has previously had an allergic reaction to the active ingredient. In addition, the drug must not be used if there are acute respiratory problems with impaired lung function or inadequate breathing capacity (respiratory insufficiency), an asthma attack or respiratory depression. Likewise, the agent must not be administered in the case of severe impaired consciousness or coma.

In addition, children under the age of twelve are not allowed to take drugs that contain codeine. The same applies to adolescents between the ages of twelve and 18 if they suffer from severe respiratory diseases.


Simultaneous use of the active ingredient with other central depressant drugs such as alcohol, tranquilizers or sleeping pills, certain psychotropic drugs (e.g. chlorpromazine) or antihistamines (e.g. promethazine) can increase the sedative and respiratory depressive effects of codeine. The use of some antidepressants (such as MAOIs) can also increase the side effects of codeine on the nervous system.

pregnancy and breast feeding period

Expectant mothers should not take codeine during pregnancy. The active ingredient can cross the placenta and thus be transferred to the fetus. It has been found that codeine can cause malformations of the airways in the embryo in the first three months. In addition, if the drug is used shortly before birth, it can cause respiratory depression in the child.

The product must not be used during breastfeeding either. The active ingredient and its intermediate products (including morphine) can accumulate in breast milk and thus be transferred to the infant. This can lead to life-threatening opioid poisoning in the child.

Driving and using machines

Since the cough suppressant codeine inhibits drive and some codeine side effects impair the patient's ability to react, active participation in road traffic and the use of machines should be avoided for the duration of the application.

This is how they get drugs with codeine

The active ingredient is in codeine tablets, as codeine drops and also as Codeine- Cough syrup available from a pharmacy against a doctor's prescription.

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