Antihistamines are medications commonly used to alleviate symptoms associated with allergies, such as hay fever, hives, and reactions to insect bites or stings. They can also address cold symptoms like sneezing and runny nose, and are sometimes used for motion sickness or short-term insomnia. It is not recommended to combine antihistamines with alcohol due to potential health risks.
How Antihistamines and Alcohol Interact
Both antihistamines and alcohol affect the central nervous system (CNS), the body’s control center. Antihistamines work by blocking histamine receptors, which can depress CNS activity. Alcohol is also a CNS depressant, slowing down the body’s responses and actions. When combined, their depressant effects are amplified, leading to a more pronounced slowing of CNS activity. This can cause vital body systems, including breathing, heart function, and brain function, to operate at a much slower rate.
Understanding the Dangers of Mixing
Mixing alcohol with antihistamines significantly increases the risk of various adverse effects. One common danger is severe drowsiness and sedation. This heightened drowsiness can lead to impaired concentration, blurred vision, and difficulty with motor control. Such impairments raise the risk of accidents, falls, and injuries, especially when driving or operating machinery.
In some cases, the combined depressant effects can lead to unresponsiveness, unconsciousness, or even a coma. Older adults may experience these side effects more intensely due to metabolism differences and a higher risk of falls. Combining these substances can also increase the risk of overdose.
Distinguishing Antihistamine Types
Antihistamines are categorized into two main types: first-generation and second-generation. First-generation antihistamines, such as diphenhydramine (Benadryl), chlorpheniramine, and hydroxyzine, are known for their sedating effects. They easily cross the blood-brain barrier, affecting the CNS. These older medications are often included in over-the-counter sleep aids due to their ability to induce drowsiness.
Second-generation antihistamines, including loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra), are considered less sedating. They are less likely to cause drowsiness because they do not cross the blood-brain barrier as readily. However, even “non-drowsy” second-generation antihistamines can still cause some drowsiness or dizziness when combined with alcohol, so caution is advised.
Guidelines for Safe Medication Use
When taking antihistamines, read the medication label carefully for warnings about alcohol consumption. If uncertain about mixing antihistamines with alcohol, consult a healthcare professional or pharmacist.
The duration an antihistamine remains in the body varies. First-generation antihistamines like diphenhydramine can have effects lasting 4 to 6 hours, but may stay in the system for up to 24 to 48 hours. Second-generation antihistamines provide relief for 24 hours and can remain in the system for a few days. It is advised to wait at least 4 to 6 hours after taking a first-generation antihistamine before consuming alcohol, and up to two days for either type to be fully cleared. If severe symptoms occur after accidentally mixing alcohol and antihistamines, seek immediate medical attention.