Tylenol with codeine is a commonly prescribed pain medication that contains two drugs, acetaminophen (Tylenol), a mild pain reliever and codeine, a narcotic Schedule III controlled substance used to treat mild to moderate pain. Tylenol with codeine that contains 30 mg of codeine is known as Tylenol #3. Both the Tylenol and the codeine components of the medication can cause side effects; some can be severe.
Acetaminophen Side Effects
Tylenol can cause liver failure if taken in amounts greater than 4,000 mg per day. Since one Tylenol with codeine tablet contains 300 mg of acetaminophen, more than 14 tablets a day could cause an overdose effect. Acetaminophen may also increase the risk of liver damage in people who drink more than 3 alcoholic drinks a day.
Codeine Side Effects
Narcotics like codeine can cause central nervous system (CNS) depression. Side effects of CNS depression are drowsiness, dizziness, light headedness, low blood pressure, slow heartbeat, small pupils and sedation. Codeine can also cause constipation, abdominal pain and nausea and vomiting.
Allergic Side Effects
Both codeine and acetaminophen can cause allergic side effects. These include rash, hives, facial swelling, difficulty breathing and circulatory collapse. Tylenol with codeine tablets contain a sulfite preservative, sodium metabisulfite. The FDA estimates that one in a hundred people has sensitivity to sulfites; the percentage of people with asthma who are sulfite sensitive is estimated to be 5 percent. Sulfites can cause an allergic reaction ranging from mild to life threatening.
Ultra Rapid Metabolizers Reaction
People with a certain genotype, CYP2D6*2x2, convert codeine rapidly to morphine, which results in higher than normal morphine levels from a normal dose of codeine. These individuals are prone to side effects such as severe drowsiness or confusion when taking Tylenol with codeine. According to RxList, the genotype is found in as many 16 to 28 percent of North Africans, Ethiopians, and Arabs, approximately 1 to 10 percent of Caucasians, and less than 1 percent of Asians. Women who are nursing should be aware of this potential reaction in themselves and their infants, as this drug passes through the breast milk.
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