Codeine and hydrocodone are opioid pain relief medications. As part of a similar drug class, they share key characteristics. However, codeine supports mild to moderate pain management, while hydrocodone is much stronger.

Codeine and hydrocodone are opioid receptor agonist medications. They connect to receptors in the brain that process pain. They work by blocking pain signals and changing how a person experiences pain.

However, they also have a high risk of addiction, and doctors prescribe them for only certain types of pain.

In this article, we assess similarities and differences between codeine and hydrocodone.

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Codeine is a natural opioid, which means it contains opium, an organic extract of poppies. It is the most commonly used opioid medication. It is available over the counter (OTC) in some countries but is available only by prescription in the United States.

Hydrocodone is a semisynthetic opioid. This means it does not contain natural opium — instead, manufacturers produce its components in a laboratory. It is also available only by prescription.

Doctors prescribe codeine for mild to moderate acute and chronic pain, often during cancer treatment or as part of supportive care for people with serious health conditions.

Pain and cough are the primary uses for which the Food and Drug Administration (FDA) has approved codeine. Some pain relief or cough and cold products combine codeine with guaifenesin or promethazine. Pain relief medication products may also contain acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs).

Hydrocodone also has FDA approval to treat pain and cough. However, doctors prescribe hydrocodone only for severe, ongoing pain that non-opioid medications do not effectively treat. It is also available in combination with acetaminophen or NSAIDs.

In its pure form, codeine is available as immediate-release oral tablets of 15 milligrams (mg), 30 mg, or 60 mg, as well as syrups. Adults usually need 15 to 60 mg every 4 to 6 hours for pain relief, with a maximum dose of 360 mg in 24 hours.

Hydrocodone is available as oral extended-release capsules. Capsules that release their dosage over 12 hours may contain 10, 15, 20, 30, 40, or 50 mg of hydrocodone. Those that release the dosage over 24 hours might provide 20, 30, 40, 60, 80, 100, or 120 mg of hydrocodone.

Immediate-release hydrocodone is available only in combination products, usually with 2.5- to 10-mg dosages. In the case of combination products including hydrocodone and acetaminophen it is essential to limit acetaminophen intake to 4 grams or less per day, as any amount larger than this poses a risk of liver toxicity.

Constipation is a common side effect of both codeine and hydrocodone use and often continues throughout treatment. People may take stool softeners and increase their fluid intake to help reduce this side effect.

Other possible side effects of codeine include:

Hydrocodone can also cause side effects such as:

Other possible side effects of hydrocodone or codeine use may include:

These are not the only side effects of either drug. Check the medication’s label and the paperwork inside the package for the full list, and report any severe side effects to the prescribing doctor.

Codeine and hydrocodone are highly effective pain relief medications, but they come with severe risks.

The Drug Enforcement Administration classifies codeine and hydrocodone in their pure forms as Schedule II drugs. This means they have a high potential for misuse and can lead to severe physical or psychological dependence.

Combination drugs containing codeine, including those combined with other non-opioid pain relief medications such as acetaminophen, have Schedule III to V classifications, which suggest low to moderate addiction potential. Combination hydrocodone products remain at Schedule II.

Stopping or reducing opioid use suddenly can lead to severe withdrawal symptoms, including:

Slowly reducing the dosage under the supervision of a doctor is the safest way to stop using opioids. Opioid withdrawal can be life threatening for some people.

People taking any opioid medication have a risk of overdose if they do not stick to the prescribed dosage. Symptoms of overdose include:

  • loss of consciousness
  • no response to sounds or movements
  • an inability to talk despite being awake
  • slow, shallow, irregular breathing
  • no breathing at all
  • skin color changes, in which the skin might turn blue or purple in people with light skin tones or gray in people with dark skin tones
  • choking sounds
  • the “death rattle,” which is a gurgling sound that resembles a snore
  • vomiting
  • limpness
  • a clammy, pale face
  • a blue, purple, or black tint to the lips and fingernails
  • a slow, irregular heartbeat
  • no heartbeat at all

In 2018, the United States Food and Drug Administration (FDA) changed the labeling on prescription cough and cold medications containing hydrocodone, ruling that they were unsafe for children younger than 18 years.

It is highly advisable to keep any products with hydrocodone locked up and out of reach of children. Even one dose of hydrocodone can result in a fatal overdose in children

Opioids, including codeine and hydrocodone, can have dangerous effects if a person takes them along with some other medications, especially those that affect the central nervous system. According to a 2023 research review, drugs in the following categories often interact with opioids:

  • antifungals
  • antibiotics
  • antivirals
  • antidepressants
  • antipsychotics
  • chemotherapy or anticancer drugs
  • antiseizure medications
  • anticholinergic drugs

Codeine and hydrocodone can also interact with sedative medications, especially benzodiazepines. Mixing these medications can affect breathing and can potentially be fatal. This combination was responsible for almost 14% of overdose deaths involving opioids in 2021.

If a doctor recommends an opioid medication to manage pain, a person should tell the doctor about any other medications they currently take. The medication’s packaging will provide a full list of possible interactions.

A doctor will make the clinical decision as to whether an opioid medication is suitable for a person and which opioid to prescribe.

Doctors usually prescribe codeine for mild to moderate pain and hydrocodone for moderate to severe pain. A doctor will assess a person’s needs and decide whether to prescribe the pure form, an immediate-release or slow-release form, or a combination medication that includes another drug.

Help is available

Seeking help for addiction may feel daunting or even scary, but several organizations can provide support.

If you believe that you or someone close to you is showing signs of addiction, you can contact the following organizations for immediate help and advice:

Codeine and hydrocodone are opioid pain relief medications that doctors prescribe to treat pain in certain situations. Hydrocodone is stronger than codeine and comes with an increased potential for addiction.

Dosages vary, but many forms of hydrocodone are slow-releasing to prevent addiction, and doctors often prescribe either drug in combination with other drugs, depending on the condition. These medications also work as cough suppressants.

People should keep opioids away from children and should not take them with certain other drugs, especially benzodiazepines.

Each medication can cause certain side effects. For example, codeine may cause dizziness or confusion, while hydrocodone may lead to itching or loss of appetite. The two medications also share some possible side effects, including nausea, sleepiness, and constipation.

Both medications pose a risk of overdose and withdrawal, so it is important to discuss dosage and tapering with a doctor.