Drug Interactions between acetaminophen / chlorpheniramine / codeine and timothy grass pollen allergen extract

Ask your doctor before using acetaminophen together with ethanol (alcohol). This can cause serious side effects that affect your liver. Call your doctor immediately if you experience a fever, chills, joint pain or swelling, excessive tiredness or weakness, unusual bleeding or bruising, skin rash or itching, loss of appetite, nausea, vomiting, or yellowing of the skin or the whites of your eyes. If your doctor does prescribe these medications together, you may need a dose adjustment or special tests to safely take both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Alcohol can increase the nervous system side effects of chlorpheniramine such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. You should avoid or limit the use of alcohol while being treated with chlorpheniramine. Do not use more than the recommended dose of chlorpheniramine, and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. Talk to your doctor or pharmacist if you have any questions or concerns.

Consuming food or beverage during or immediately after using timothy grass pollen allergen extract may reduce the amount of allergen extract available for absorption from tissues under the tongue into the blood stream. Food or beverage should not be taken with, or for at least 5 minutes after, using timothy grass pollen allergen extract. Use of alcohol with timothy grass pollen allergen extract may increase the risk and severity of allergic reactions that can sometimes occur during treatment with timothy grass pollen allergen extract. Potentially life-threatening or fatal reactions may occur. Talk to your doctor if you have any questions or concerns. Stop using timothy grass pollen allergen extract, administer epinephrine, and seek immediate medical attention if signs and symptoms of an allergic reaction develop such as trouble breathing, swallowing, or speaking; throat tightness or swelling; dizziness, lightheadedness, or fainting; rapid or weak heartbeat; severe stomach cramps or pain; vomiting or diarrhea; and/or severe flushing or itching. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Do not use alcohol or medications that contain alcohol while you are receiving treatment with codeine. This may increase nervous system side effects such as drowsiness, dizziness, lightheadedness, difficulty concentrating, and impairment in thinking and judgment. In severe cases, low blood pressure, respiratory distress, fainting, coma, or even death may occur. With certain long-acting formulations of narcotic pain medication, consumption of alcohol may also cause rapid release of the drug, resulting in high blood levels that may be potentially lethal. Talk to your doctor or pharmacist if you have questions on how to take this or other medications you are prescribed. Do not use more than the recommended dose of codeine, and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medication without first talking to your doctor.

Consumer information for this interaction is not currently available.

MONITOR: Smoking cessation may lead to elevated plasma concentrations and enhanced pharmacologic effects of drugs that are substrates of CYP450 1A2 (and possibly CYP450 1A1) and/or certain drugs with a narrow therapeutic index (e.g., flecainide, pentazocine). One proposed mechanism is related to the loss of CYP450 1A2 and 1A1 induction by polycyclic aromatic hydrocarbons in tobacco smoke; when smoking cessation agents are initiated and smoking stops, the metabolism of certain drugs may decrease leading to increased plasma concentrations. The mechanism by which smoking cessation affects narrow therapeutic index drugs that are not known substrates of CYP450 1A2 or 1A1 is unknown. The clinical significance of this interaction is unknown as clinical data are lacking.

MANAGEMENT: Until more information is available, caution is advisable if smoking cessation agents are used concomitantly with drugs that are substrates of CYP450 1A2 or 1A1 and/or those with a narrow therapeutic range. Patients receiving smoking cessation agents may require periodic dose adjustments and closer clinical and laboratory monitoring of medications that are substrates of CYP450 1A2 or 1A1.