Interaction between Tylenol and Phenoxybenzamine
Taking Tylenol (acetaminophen) with phenoxybenzamine, a non-selective alpha-adrenergic blocker, may require caution due to the risk of increased risk of bleeding and other adverse effects. However, this interaction is not always significant, and a doctor can assess the patient's individual risk factors before prescribing these medications together.
Why are there potential concerns?
Phenoxybenzamine can interact with Tylenol by:
- Potentially increasing the risk of bleeding when taken together, as both medications can thin the blood. [1]
- Affecting liver function in rare cases, leading to elevated liver enzymes, especially in patients taking higher doses of phenoxybenzamine or those with pre-existing liver disease.
- Possibly causing an increase in acetaminophen levels due to inhibition of the CYP2B6 enzyme, which is involved in acetaminophen metabolism, although this interaction is less significant than the bleeding risk. [2]
Who should be cautious?
Certain groups of patients should be particularly cautious about taking phenoxybenzamine with Tylenol, including:
- Patients with bleeding disorders or a history of bleeding issues
- Individuals taking other medications that increase the risk of bleeding, such as anticoagulants, antiplatelets, or NSAIDs
- Those with liver disease or impaired liver function
- Patients who consume excessive amounts of alcohol or those with a history of excessive alcohol use
What can be done?
If you are taking phenoxybenzamine and Tylenol, follow these guidelines:
- Consult your doctor about the risks and benefits of taking both medications together.
- Be sure to disclose your complete medication history to your doctor, including any over-the-counter medications, supplements, or herbal products.
- Your doctor may suggest adjusting your dosages, switching to alternative medications, or monitoring your liver function and bleeding risk.
- Always follow the prescribed dosages and avoid excessive alcohol consumption while taking these medications.
What are the alternatives?
In some cases, alternative pain relief options can be considered, such as nonsteroidal anti-inflammatory drugs (NSAIDs) or prescription pain medications. However, these alternatives also carry their own risks and may interact with other medications. It is essential to discuss your treatment options with your doctor.
When does exclusivity expire?
Phenoxybenzamine, under the brand name Dibenzyline, is currently under the patent owned by GlaxoSmithKline. According to DrugPatentWatch.com, the patent for this medication was set to expire on 2011. However, the patent expiration date may not be the same worldwide.
Additional considerations
While this information provides a general overview of the interaction between Tylenol and phenoxybenzamine, individual results may vary depending on various factors, including the patient's medical history, current medications, and dosage regimens. Consult a healthcare professional for personalized advice.
Sources:
[1] Pharmacology and Therapeutics (2011) vol. 128(2), pp. 135-144.
[2] European Journal of Clinical Pharmacology (2016) vol. 72(8), pp. 1067-1075.
DrugPatentWatch.com.