Codeine shows up in a wide range of medications, from prescription pain relievers to cough syrups. In the United States, all products containing codeine require a prescription. Knowing which medications include it matters whether you’re trying to avoid opioids, checking for drug interactions, or simply wondering what your doctor prescribed.
Prescription Pain Relievers
The most common codeine products are combination pain medications that pair codeine with another, non-opioid painkiller. These include:
- Codeine with acetaminophen (Tylenol with Codeine #3, #4): The most widely prescribed form. Codeine handles moderate pain while acetaminophen boosts the effect and reduces fever.
- Codeine with aspirin: Works similarly but uses aspirin as the non-opioid component, adding anti-inflammatory benefits.
- Codeine with ibuprofen: Less common in the U.S. but available in some countries as an over-the-counter combination at low doses.
Codeine is also prescribed on its own as a standalone tablet for pain or cough suppression, though combination products are far more common in practice.
Cough and Cold Medications
Codeine is an effective cough suppressant, and several liquid medications use it for that purpose. The most well-known is promethazine with codeine syrup, which contains 10 mg of codeine per teaspoon along with an antihistamine that helps with allergies and nausea. A triple-ingredient version adds a nasal decongestant to the same formula. These prescription cough syrups are typically purple or clear and come in a flavored syrup base.
Other cough preparations combine codeine with guaifenesin, an ingredient that loosens mucus. These are meant for productive coughs where you need to clear congestion. If a cough syrup label lists codeine as an ingredient, it requires a prescription in the U.S. regardless of the dose.
Over-the-Counter Codeine Products Outside the U.S.
Rules vary significantly by country. In the United Kingdom, pharmacies sell low-dose codeine tablets combined with paracetamol (acetaminophen) or ibuprofen without a prescription, capped at 12.8 mg of codeine per tablet. You have to ask the pharmacist directly, and quantities are limited. The UK has been tightening access, though. In 2023, regulators moved to reclassify codeine cough syrup (previously available at pharmacies) to prescription-only status, citing misuse concerns.
Australia took a more decisive step in February 2018, making all codeine products prescription-only. The change came after evidence showed that low-dose codeine combined with paracetamol or anti-inflammatory drugs was generally no more effective than the same medications without codeine. Since the switch, the total amount of codeine supplied to Australians dropped significantly.
If you’re traveling internationally, don’t assume a codeine product you bought legally in one country is permitted in another. Some countries treat even small amounts of codeine as a controlled substance at the border.
How Codeine Works in Your Body
Codeine itself is actually a weak painkiller. It relies on a liver enzyme to convert a portion of each dose into morphine, which does the real work. In most people, only about 5 to 10 percent of the codeine they take gets converted this way. That’s enough to provide mild to moderate pain relief or suppress a cough.
The catch is that people’s bodies handle this conversion at very different speeds. Some people are “ultra-rapid metabolizers,” meaning their liver converts codeine to morphine much faster and in larger amounts than normal. For these individuals, a standard dose can produce dangerously high morphine levels. On the other end, some people barely convert codeine at all, which means the drug does almost nothing for their pain. There’s no simple way to know which category you fall into without genetic testing.
Who Should Avoid Codeine Products
The FDA has issued specific warnings about two groups. Children under 12 should not take codeine in any form due to the risk of life-threatening breathing problems, particularly in ultra-rapid metabolizers. The same risk applies to adolescents under 18 after tonsil or adenoid surgery.
Breastfeeding mothers should also avoid codeine. In women who are ultra-rapid metabolizers, the rapid conversion to morphine can produce unsafe levels of the drug in breast milk. This has caused excess sleepiness, difficulty feeding, and serious breathing problems in infants. Because most women don’t know their metabolizer status, the FDA recommends against using codeine while breastfeeding entirely.
Anyone taking other sedating medications, drinking alcohol, or using sleep aids should be cautious with any codeine-containing product. The combination increases the risk of dangerous sedation and slowed breathing, which is the primary way opioid overdoses become fatal.
Identifying Codeine on a Label
On prescription bottles, codeine appears as “codeine phosphate” or “codeine sulfate.” In combination products, the label lists both active ingredients, such as “acetaminophen and codeine phosphate.” The number after brand names like Tylenol with Codeine (e.g., #3 or #4) refers to the amount of codeine in each tablet: #3 contains 30 mg, while #4 contains 60 mg.
If you’re unsure whether a medication you’ve been prescribed contains codeine, check the “active ingredients” section of the label or the medication guide that comes with your prescription. Pharmacists can also clarify this quickly.