Allergies, Cough/Cold Medications and Alcohol Interactions

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on May 20, 2024.

Combining some cough, cold and allergy medicines with alcohol can result in serious drug interactions and side effects like worsened drowsiness, dizziness, confusion and trouble driving. Many of these medicines are bought over-the-counter (OTC), so always follow the labels and check with your healthcare provider if you have questions.

Introduction

Allergy, cough, cold and flu medications are commonly bought without a prescription and are used to treat symptoms such as:

• sneezing
• hives, swelling and itching
• runny nose
• nasal congestion
• coughing
• itchy and watery eyes

Interactions with alcohol and over-the-counter (OTC) medications like antihistamines are especially worrisome, as OTCs are often bought without advice from your doctor or pharmacist. Allergy medication or cold medicine, when mixed with alcohol (also called ethanol), can commonly lead to worsened side effects such as drowsiness, sedation, difficulty concentrating, and dizziness. Driving or other activities can become hazardous.

Many allergy medicines are available as both brand and generic products commonly found in pharmacies, grocery stores, other retail shops, or bought online. Some antihistamines or other cough and cold drugs may require a prescription from your doctor.

You should avoid or limit the use of allergy medicine that makes you drowsy and alcohol. Check the package labeling for any specific wording and ask your pharmacist or doctor for recommendations. Avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you.

Also, if you take an antihistamine at a higher dose than recommended or consume excessive amounts of alcohol, the side effects of this interaction can be worse for people with the following medical conditions:

• enlarged prostate
• epilepsy
• overactive thyroid
• heart disease
• diabetes
• liver problems

Learn More: Alcohol (Ethanol) Drug Interactions

Antihistamines

Antihistamines work by blocking histamine release from the body when an allergen is encountered. Antihistamines can be classified as first generation (sedating) antihistamines and second generation (non-sedating) antihistamines. Antihistamines are most commonly used for allergic reactions, hay fever, cold and flu symptoms, or hives, but can also be used as a medication to help with sleep or for motion sickness.

• First generation antihistamines are more likely to cause drowsiness as they work in the brain and spinal cord to block the histamine-1 (H-1) receptor, as well as other receptors in the body. These drugs, like Benadryl, cause significant drowsiness for most people.
• Second generation antihistamines cause less or no drowsiness because they primarily work on the H-1 receptors outside the brain. However, cetirizine (Zyrtec) may cause significant drowsiness in up to 15% of people, especially with higher doses.

Antihistamines may be bought as a single agent or in combination with decongestants like phenylephrine or pseudoephedrine. They can also be found combined with fever, headache and pain relievers like acetaminophen or ibuprofen, added to cough suppressants like dextromethorphan, or mixed with cough medicines like guaifenesin.

• For example, Vicks Nyquil Cold & Flu Nighttime Liquid contains a fixed-dose mixture of acetaminophen (pain and fever relief), doxylamine (a sedating antihistamine), and dextromethorphan (a cough suppressant).
• TheraFlu Daytime Severe Cough and Cold Liquid contains acetaminophen, dextromethorphan and phenylephrine (a decongestant).
• Some OTC cough, cold and flu medicines like Vicks Nyquil may contain alcohol which can worsen drowsiness if mixed with alcoholic beverages. Mixing alcohol with Nyquil should be avoided.

Always check the label on the over-the-counter or prescription medications to review for interactions with alcohol.

Sedating antihistamines

• Commonly used sedating antihistamines and brand name examples include:
  • azelastine nasal spray (Astepro, Astelin)
  • diphenhydramine (Benadryl, ZzzQuil)
  • chlorpheniramine
  • brompheniramine (Dimetapp)
  • doxylamine (Unisom)

Non-sedating antihistamines

• Commonly used non-sedating antihistamines and brand name examples include:
  • loratadine (Alavert, Claritin, Claritin-D)
  • desloratadine (Clarinex)
  • fexofenadine (Allegra)
  • cetirizine (Zyrtec)
  • levocetirizine (Xyzal Allergy 24)

Even though some antihistamines are classified as non-sedating, drowsiness can still occur in a small number of people, and may be worse for those who take Zyrtec compared to other non-drowsy antihistamines.

Cough Suppressants

Dextromethorphan (Delsym, Benylin DM) is a widely used cough suppressant that can lead to drowsiness, dizziness, disorientation, and impairment of judgement.

• You should avoid the combined use of cough syrups containing dextromethorphan and alcohol as this mixture can worsen drowsiness and other CNS side effects like dizziness or confusion. 
• Do not drive, operate machinery or engage in hazardous activities while using dextromethorphan. Never drink alcohol and then drive.

Codeine is found in some cough suppressants that are narcotic-based (example: Cheratussin AC) and can lead to major drowsiness, dizziness lack of judgement and other CNS side effects. Narcotic-based cough suppressants should not be combined with alcohol due to additive drowsiness and possible respiratory depression (slowed or stopped breathing), which may be fatal.

• You may find that some products combine these cough suppressants with other medicines like guaifenesin, an expectorant.
• Codeine cough suppressants like Cheratussin AC now require a prescription in most of the U.S., but controlled substances rules can vary between states.

Related: Medications for Cough and Nasal Congestion

Sustained-release formulations of hydrocodone, such as Tussicaps (chlorpheniramine and hydrocodone) also should not be consumed with alcohol.

• Alcohol combined with some sustained-release formulations of hydrocodone may cause a rapid release of the drug, resulting in high blood levels of hydrocodone that may be potentially lethal.
• You should NOT combine ANY narcotic, including codeine and hydrocodone, with alcohol due to additive CNS and respiratory depression that could be fatal.

The cough suppressant benzonatate (Tessalon Perles) does not contain a narcotic agent and does not list alcohol as a possible drug interaction. But sedation, headache, dizziness, mental confusion, and visual hallucinations are listed as possible side effects to benzonatate and could have an additive effect with alcohol side effects, which may be similar.

Guaifenesin (Mucinex) is an expectorant that thins mucus to help relieve chest congestion. Alcohol does not interact with guaifenesin by itself, but guaifenesin may be found in combination products that contain dextromethorphan, antihistamines, or other sedating ingredients that may interact.

Codeine, phenylephrine, and promethazine (Phenergan VC with codeine - brand name now discontinued) is a combination medicine used for the temporary relief of coughs, sneezing, runny nose or nasal congestion associated with allergy or the common cold in adults. Promethazine is classified as a phenothiazine with antihistamine (H-1) properties. It is also used as a single agent for sedation, post-surgical nausea and vomiting, and motion sickness.

• This product may also contain codeine and you should NOT combine it with alcohol due to the risk for sedation and respiratory depression (slowed or stopped breathing, which may be fatal).
• The combination of promethazine and alcohol can lead to uncontrollable muscle movements, agitation, seizures, dizziness, fainting, coma, very deep sleep, irregular heartbeats, and high or low body temperature.
• Do not drive, operating machinery, or performing other hazardous activities while using this medication.

Visit the Drugs.com Interaction Checker to review drug interactions with all of your medications.

Common Allergy, Cough, and Cold Medicines

*Note: N/A - not available. These ingredients may be found in prescription and / or  OTC products. This is not a complete list; always check with your pharmacist for possible medication and alcohol drug interactions. Review the OTC Drug Facts label or prescription warnings on every package.

If you have any questions, ask your pharmacist or doctor for help. Always follow the label directions. Tell your healthcare providers about all the other medications you use, including prescription, over-the-counter (OTC) drugs, vitamins, dietary supplements and herbal products.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer