The common cold is a mild, self-limiting respiratory illness caused primarily by rhinoviruses, typically resolving within seven to ten days. Recovery relies heavily on the body’s natural defenses and supportive care. Consuming alcohol during an illness introduces biological and pharmacological risks that can complicate the healing process. Understanding how alcohol interacts with the immune system, cold symptoms, and medications is necessary for making an informed health choice.
Alcohol’s Impact on Immune Function
Alcohol consumption directly affects the processes the body uses to fight off the viral invaders responsible for the common cold. Introducing alcohol can hinder the immune response when the body is already working to neutralize a virus. Alcohol impairs the function of white blood cells, the immune system’s primary defense agents.
Acute alcohol intake reduces the ability of these white blood cells, including T-lymphocytes and natural killer cells, to multiply and effectively target infected cells. This suppression occurs when the immune system needs to be operating efficiently to clear the virus. Alcohol also interferes with cytokines, the signaling molecules immune cells use to communicate and coordinate an attack.
Cytokines help regulate inflammation and direct immune traffic to the site of infection. Disrupting this communication can lead to an imbalanced or ineffective immune response. Even a single episode of heavy drinking can compromise the body’s defenses for several hours, potentially prolonging the duration or severity of the cold. By weakening internal defenses, alcohol makes it more difficult for the body to shorten the course of the infection.
Exacerbation of Physical Cold Symptoms
The immediate physical effects of alcohol often make existing cold symptoms feel worse. Alcohol is a diuretic, meaning it promotes the loss of fluid from the body by suppressing the release of antidiuretic hormone (ADH). This suppression causes the kidneys to excrete water at a higher rate, leading to dehydration.
A body fighting a cold requires increased fluid intake, and dehydration aggravates common symptoms. It can thicken mucus, worsening nasal and chest congestion and making breathing harder. Dehydration also contributes to headaches and throat irritation, symptoms associated with a cold.
Sleep is a necessary component of recovery, allowing the body to dedicate energy to healing. Alcohol disrupts the natural sleep cycle, particularly the restorative rapid eye movement (REM) sleep stage. Though it may initially induce drowsiness, alcohol leads to fragmented and lower-quality rest, hindering recovery and leaving a person fatigued.
Dangerous Interactions with Cold Medications
The most serious risk of drinking alcohol with a cold is the potential for dangerous interactions with common over-the-counter (OTC) cold medications. Many multi-symptom remedies contain ingredients that can become toxic or cause severe side effects when combined with ethanol. Always read the drug facts label on any medication before consuming alcohol.
Acetaminophen
Acetaminophen, a common pain reliever and fever reducer found in many cold products, is metabolized in the liver, as is alcohol. When processed, a small amount of a toxic byproduct called N-acetyl-p-benzoquinone imine (NAPQI) is produced. The liver normally detoxifies this compound using glutathione.
Alcohol increases the activity of the liver enzyme CYP2E1, resulting in greater production of the toxic NAPQI metabolite. Alcohol also depletes the liver’s supply of glutathione, reducing the body’s capacity to neutralize the toxin. The combination of increased toxin production and reduced detoxification raises the risk of severe, potentially fatal, liver damage. The risk is especially high for individuals who regularly consume alcohol.
Antihistamines
Antihistamines, such as diphenhydramine (often found in nighttime cold formulas), are central nervous system (CNS) depressants that cause drowsiness. Alcohol is also a CNS depressant; combining the two substances drastically intensifies their sedative effects. This combination can lead to extreme drowsiness, dizziness, impaired motor coordination, and reduced reaction time.
The combined CNS depression can increase the risk of accidental injury or fall, and may lead to respiratory depression. Even newer, less-sedating antihistamines should be used with caution, but first-generation antihistamines must be strictly avoided with alcohol.
Decongestants
Decongestants like pseudoephedrine and phenylephrine work by narrowing blood vessels to reduce swelling in the nasal passages. These medications are stimulants that can increase heart rate and blood pressure. Alcohol consumption can exacerbate these side effects, potentially causing a rapid heart rate, heart palpitations, or increased anxiety.
Combining alcohol with these stimulants creates a conflicting physiological effect that can put strain on the cardiovascular system. The stimulating effect of decongestants can sometimes mask the initial signs of alcohol intoxication, potentially leading a person to drink more than they normally would. This increases the risk of adverse reactions and impaired judgment.