Codeine Side Effects | Common & Rare

Codeine has a number of different side effects.

Codeine is an opioid pain reliever (or opiate analgesic) used to treat mild to severe pain and reduce coughing. Depending on its form, the FDA classifies codeine as a schedule II, III, and V controlled substance. In its purest form, it can have a high potential for abuse.

When used for pain relief, it works by changing how the central nervous system responds to pain. When used to reduce coughing, it decreases the activity in the part of the brain that leads to coughing.

While it can help those who need it, codeine also comes with a variety of side effects. Some are very common, while others are rare.

Common Side Effects Of Codeine

Codeine has a number of different side effects, but the most common side effects of the medication include:

  • constipation
  • drowsiness
  • sedation
  • excessive sweating
  • nausea/vomiting
  • stomach cramps
  • dizziness
  • blurred vision
  • difficulty urinating
  • tremors
  • weakness
  • pancreatitis

While these side effects may be common, you should still let your healthcare provider know if you experience them. They may be able to do something to lessen their intensity.

Rare Side Effects Of Codeine

Codeine also has some rare adverse effects. If you experience one or more of these uncommon side effects, your doctor should be informed as soon as possible as some of them can be life-threatening.

The rare side effects include:

  • collapsed lung
  • decreased lung function
  • alertness
  • dry mouth
  • fainting
  • decreased appetite
  • headache
  • lightheadedness
  • addiction
  • slow heartbeat
  • fast heart rate
  • weak pulse
  • shallow breathing
  • seizures
  • sleep apnea
  • shock
  • mental health issues
  • stomach pain
  • clammy skin
  • diarrhea
  • anxiety
  • poor coordination

Allergic Reactions To Codeine

You should also be on the lookout for signs that you are allergic to the medication. Allergy symptoms can look similar to side effects but can become very serious if you continue taking the drug. An allergic reaction to codeine can look like:

  • itching
  • hives
  • rash
  • blisters
  • swelling of the mouth, neck, or face
  • severely low blood pressure
  • trouble breathing

Precautions Before Taking Codeine

Codeine should also not be taken when you have certain pre-existing conditions. If you have any of the following issues, you need to tell your healthcare professional. They will likely give you a different medication as codeine can make these conditions worse.

  • brain disorders like a head injury, tumor, or seizures
  • breathing problems like asthma, sleep apnea, or COPD
  • kidney disease
  • liver disease
  • mental health disorders
  • history of a substance use disorder
  • obesity
  • stomach or intestinal problems
  • difficulty urinating
  • gallbladder disease
  • pancreatitis

Drug Interactions With Codeine

Some other substances and medications should not be taken with codeine as they can make the side effects worse. The substances listed below do not interact well with codeine:

  • alcohol
  • benzodiazepines like diazepam (Valium) and alprazolam (Xanax)
  • cannabis
  • other opioids
  • monoamine oxidase inhibitors (MAOIs)
  • sleep aids like Ambien

Beyond not taking codeine with these drugs, codeine should also not be taken while breastfeeding. It passes into the breast milk and once a baby has ingested it, it can cause some serious side effects including sleepiness, breathing problems, and even death.

Codeine Withdrawal Symptoms

If you’ve been taking high doses of codeine or using it for an extended period of time, there is a chance of building up a tolerance or a physical dependence. This is especially the case if the codeine is mixed with acetaminophen.

Once a dependence is built up, your body can no longer function properly without the drug, and quitting it can lead to a number of unpleasant withdrawal symptoms including:

  • feeling irritable
  • anxiousness
  • trouble sleeping
  • teary eyes
  • runny nose
  • sweating
  • yawning
  • muscle aches
  • fast heartbeat
  • loss of appetite
  • stomach cramps
  • diarrhea
  • enlarged pupils
  • chills

If you or a loved one lives with issues related to drug abuse or addiction, contact us today for information on our outpatient rehab programs.

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