Side effects | Codeine

Side effects

Since the main effects of codeine are caused by an action on the brain, it is not surprising that this substance can have a variety of side effects. Very often (in up to 10%) nausea occurs after ingestion due to the irritation of the vomiting centre in the brain and/or the effect on the gastrointestinal tract, which can lead to vomiting. An excessive slowing down of the stomach and intestinal movements can cause constipation with no bowel movement (also in up to 10% of cases).

Due to this side effect, laxative medication must often be taken in addition to codeine. Like any opiate, codeine can lead to inhibition of the respiratory drive in the case of overdose. This can lead to a life-threatening flattening and slowing of breathing up to respiratory arrest.

Existing respiratory problems such as asthma or COPD may be exacerbated or re-induced. The first sign of an overdose is severe drowsiness, which may extend to unconsciousness. In addition, narrow pupils, vomiting and headaches can be observed.

At these signs a doctor should be consulted immediately to avoid a life-threatening situation. If respiratory arrest occurs, the effect of codeine can be reversed with naloxone. Furthermore, all opiates can lead to a temporary feeling of elation.

For this reason codeine is misused as a narcotic. It should be noted that it can cause addiction if used too long and heavily. Possible side effects are also: especially in children, cramps can be triggered.

Codeine can interact with many drugs that act on nerves in the brain. Alcohol should not be taken during treatment with opiates, because a combination of these 2 substances has an even greater effect on consciousness and further increases the likelihood of breathing deterioration. If you have any questions about interactions with certain drugs, please refer to the package insert or discuss taking codeine with your prescribing doctor.

  • Sudden fainting
  • Drowsiness
  • Headaches and
  • Drop in blood pressure, which can lead to weakness and dizziness. In principle, codeine can be used during pregnancy. Since the drug also affects the child’s organism, damage cannot be ruled out.

However, previous studies have not found any harmful effects of codeine on the unborn child. Codeine should be avoided shortly before delivery as it can restrict the newborn’s normal breathing and cause respiratory arrest. As codeine or the portion converted to morphine also passes into breast milk and can thus have an effect on the breastfed baby, codeine should only be taken for a maximum of 2-3 days during the breastfeeding period in order to avoid side effects in the baby.

However, it should be noted that the rate of conversion depends on certain enzymes, such as the CYP2D6 enzyme, which work particularly quickly in a few percent of the population. Other genes can also speed up the conversion process and thus extremely increase the morphine level in a very short time, which in the worst case can lead to the death of the newborn through the absorption of morphine through breast milk. Therefore, when taking codeine and similar morphine-containing painkillers, it should be weighed up in a medical consultation.