Codeine and hydrocodone are both opioid medications, but there are many differences between these drugs. It’s important to be aware of the risks and benefits of each.

Codeine and hydrocodone are both prescription opioid medications that can be used to treat similar conditions, but there are some important differences between each drug. The following provides an overview of how these drugs are used, the notable differences between them and the risks related to opioid use.

What Is Codeine?

Codeine is an opioid that’s prescribed for the treatment of mild pain and cough. Compared to most prescription narcotics, codeine is relatively low-potency. While someone who takes codeine may experience an increased pain tolerance, they will likely know the pain is still there. This is why it’s often combined with other drugs, such as acetaminophen, to improve medicinal effects.

Although codeine is less potent than many other opioids, it still carries the risk of addiction, physical dependence and overdose. This risk can vary with the product, so codeine preparations range from Schedule II to Schedule V controlled substances.

What Is Hydrocodone?

Hydrocodone is another opioid pain medication that’s often used in combination with acetaminophen. Hydrocodone is a relatively potent prescription painkiller, meaning it is more powerful than codeine.

Hydrocodone is also addictive, and the development of physical dependence isn’t uncommon with this drug. The drug is a Schedule II controlled substance. It can also be misused to get high. When someone takes larger doses of hydrocodone, they may feel euphoric sensations and then become very tired and relaxed.

Codeine vs. Hydrocodone

Codeine and hydrocodone are both used to treat pain and suppress the cough reflex in the brain. However, there are key differences between the two drugs. These include:

  • The drugs have different chemical structures. Hydrocodone is a semi-synthetic opioid, meaning that it is partially man-made. In contrast, codeine is a natural opioid derived from opium.
  • Some people may not get any effect from codeine. If a person lacks a liver enzyme called CYP2D6 that turns codeine into morphine in the body, they won’t feel effects. This isn’t the case with hydrocodone.
  • Hydrocodone is significantly stronger than codeine. For this reason, it has more sedative effects and is more effective for treating severe pain.

As opioid drugs, codeine and hydrocodone bind to opioid receptor sites in the brain and slow down the central nervous system. This is why people can overdose on opioids — these drugs can slow the activity of the central nervous system to the point where respiration slows down or even stops entirely.

Codeine vs. Hydrocodone Cough Syrup

Both codeine and hydrocodone can be prescribed to treat a cough. Codeine cough syrup is considered pretty mild. In some states, cough syrups with low amounts of codeine may be available over the counter as Schedule V controlled substances. In contrast, hydrocodone cough syrup is not approved for use in the United States but is available in Canada.

Hydrocodone cough syrup is often used in patients who have a cough as well as severe pain. For example, it may be used for patients who have a cough due to lung cancer. Hydrocodone cough syrup tends to be more effective than codeine for pain and cough, but it also has a higher risk of abuse and addiction.

Drug Allergy and Allergy-Like Side Effects

People frequently believe they’re having an allergic reaction to codeine because they experience symptoms like nausea and itching. However, these are normal side effects of codeine; true codeine allergies are rare. These side effects occur because codeine activates a histamine response that’s similar to what happens when someone has an allergic reaction. Compared to codeine, hydrocodone is less likely to cause this side effect.

Some patients who do have a codeine allergy may tolerate hydrocodone better due to differences in the chemical structure of each drug.

Codeine vs. Hydrocodone Conversion

Hydrocodone is much more powerful than codeine. In fact, codeine is only about 15% as strong as hydrocodone. This makes hydrocodone more effective for pain relief, and the drug also has fewer allergy-like side effects. However, hydrocodone increases the risk of addiction, dependence and overdose.

If you or someone you love is struggling with opioid addiction or dependence, The Recovery Village is here to help. Contact us today to learn more about opioid addiction treatment programs that can work well with your situation and recovery needs.

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Editor – Jonathan Strum
Jonathan Strum graduated from the University of Nebraska Omaha with a Bachelor's in Communication in 2017 and has been writing professionally ever since. Read more
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Medically Reviewed By – Dr. Jessica Pyhtila, PharmD
Dr. Jessica Pyhtila is a Clinical Pharmacy Specialist based in Baltimore, Maryland with practice sites in inpatient palliative care and outpatient primary care at the Department of Veteran Affairs. Read more

American Academy of Family Physicians. “Opioid Conversion Table.” Accessed August 14, 2021.

Pratt, V.M., Scott, S.A., Pirmohamed, M., et al. “Codeine Therapy and CYP2D6 Genotype.” Medical Genetics Summaries, March 30, 2021. Accessed August 14, 2021.

Drug Enforcement Administration. “Controlled Substances.” July 20, 2021. Accessed August 14, 2021.

HealthLinkBC. “Hydrocodone Liquid – Oral.” Accessed August 14, 2021.

Sheen, C.H., Schleimer, R.P., Kulka, M. “Codeine induces human mast cell chemokin[…]G-protein activation.” Allergy, January 15, 2008. Accessed August 14, 2021.

Zhang, B., Li, Q., Shi, C., Zhang, X. “Drug-Induced Pseudoallergy: A Review of […]auses and Mechanisms.” Pharmacology, November 15, 2017. Accessed August 14, 2021.

Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.