Over the Counter (OTC) Drugs

Dextromethorphan (DXM) is a cough suppressant found in many over the counter cold and flu medicines. It changes how nerve signals involved in the cough reflex are processed, making the brain less likely to trigger a cough. DXM is often found in syrups, liquids, tablets, and gel capsules. Many products contain DXM along with other ingredients such as acetaminophen (the active ingredient in Tylenol), antihistamines, or decongestants. 

When used as directed, DXM is generally safe. Problems can happen when large amounts are taken or when it is mixed with other substances. 

Short- and Long-term effects 

At recommended doses, DXM helps relieve a cough. At high doses, it can affect the brain in ways that change perception and awareness. 

Short-term effects 

• Confusion or agitation 
• Dizziness 
• Hallucinations or dissociation at high doses 
• Increased heart rate 
• Loss of coordination 
• Nausea or vomiting 
• Slurred speech 

There may also be a higher risk of accidents or injuries because judgment and coordination can be affected. 

Long-term effects 

Repeated misuse may lead to: 

• Increased anxiety or depression 
• Memory or concentration problems 
• Tolerance (needing more to feel the same effect) 

Safety note 

Many DXM products contain other active ingredients. Taking large amounts increases the risk of serious harm, such as liver damage from acetaminophen (Tylenol) or dangerous interactions with other medications. Tylenol-associated liver failure is a painful, potentially life-threatening event. 

Mixing DXM with alcohol, other drugs, or medications that affect serotonin can increase the chance of serious reactions such as serotonin syndrome, a potentially life-threatening condition. 

Seek medical help right away if someone has trouble breathing, severe confusion, seizures, or cannot be woken up. 

Diphenhydramine is an antihistamine used to treat allergies, itching, and cold symptoms. It works by blocking histamine, a chemical the body releases during allergic reactions. Histamine can cause symptoms like sneezing, itching, and watery eyes. 

Diphenhydramine also affects signals in the brain that control alertness, which is why it can cause drowsiness. It is sometimes used as a sleep aid because of this effect. 

Problems can occur when people take larger doses than recommended or use it to change how they feel.

Short- and Long-term effects  

At recommended doses, Allergy medication is safe and helps relieve allergy symptoms. 

Short-term effects 

Possible short-term effects include: 

• Blurred vision 
• Confusion or agitation 
• Drowsiness 
• Dizziness 
• Dry mouth 
• Increased heart rate 
• Trouble concentrating 

At very high doses, diphenhydramine can cause: 

• Dangerous heart rhythm problems 
• Hallucinations 
• Overheating 
• Seizures 
• Severe confusion 

Long-term effects 

Repeated misuse may lead to: 

• Heart rhythm problems
• Increased risk of falls or injury 
• Memory problems 
• Ongoing confusion 

Older adults may be especially sensitive to these effects.

Safety note 

Many allergy medicines and sleep aids contain diphenhydramine or similar antihistamines. Taking several products together can increase the risk of harm. 

Seek medical help right away if someone has seizures, severe confusion, or trouble staying awake. 

Some over-the-counter sleep aids are designed to help people fall asleep or stay asleep. Many contain sedating antihistamines, such as the one in Benadryl. 

These medicines slow signals in the brain, which can make people feel sleepy. 

They may help with short-term sleep problems, but they are not meant for long-term or frequent use.

Short- and Long-term effects  

Short-term effects 

Possible short-term effects include: 

• Blurred vision 
• Confusion 
• Dizziness 
• Dry mouth 
• Slowed reaction time 
• Strong drowsiness 

There may be a higher risk of falls or accidents because coordination and alertness can be affected.

Long-term effects 

Repeated misuse may lead to: 

• Confusion or slowed thinking 
• Daytime fatigue 
• Memory problems 
• Trouble sleeping without medication 

Using high doses can increase the risk of serious side effects such as heart rhythm problems or severe confusion. 

Safety note 

Many sleep aids contain the same ingredients as allergy medicines. Taking more than one product with the same ingredient can increase the risk of harm. 

If sleep problems continue, talking with a health care provider may help identify safer options. 

Imodium is the brand name for the generic drug loperamide. Both contain the same active ingredient and work the same way to treat diarrhea. It works by slowing movement in the intestines, which helps the body absorb more fluid and reduce bowel movements. 

When used as directed, loperamide is generally safe. Problems can occur when it is taken in much higher amounts than recommended. 

Short- and Long-term effects  

Short-term effects 

At recommended doses, loperamide helps relieve diarrhea. At high doses, it can affect the heart and nervous system. 

Possible short-term effects include: 

• Constipation 
• Dizziness  
• Drowsiness 
• Nausea  

At very high doses: 

• Fainting  
• Irregular or dangerous heart rhythms  
• Loss of consciousness 

Long-term effects 

Repeated misuse may lead to: 

• Dependence 
• Increased risk of overdose  
• Serious heart rhythm problems

Safety note 

High doses of anti-diarrheal medication can cause life-threatening heart rhythm changes. 

Seek medical help right away if someone has fainting, an irregular heartbeat, or trouble staying awake. 

Decongestants are used to relieve nasal congestion from colds or allergies. They work by narrowing blood vessels in the nasal passages, which reduces swelling and helps you breathe more easily. 

Common ingredients include pseudoephedrine and ephedrine. These are also stimulants, meaning they can increase alertness and affect heart rate and blood pressure. 

Decongestants are often combined with other ingredients in cold and flu products, such as antihistamines, cough suppressants, or pain relievers. 

Short- and Long-term effects  

Short-term effects 

When used as directed, decongestants can reduce congestion. Misuse or higher doses can overstimulate the body. 

Possible short-term effects include: 

• Elevated blood pressure 
• Headache 
• Increased heart rate  
• Restlessness or nervousness  
• Trouble sleeping  

At high doses: 

• Anxiety or agitation  
• Irregular heartbeat  
• Muscle tremors 

Long-term effects 

Repeated misuse may lead to: 

• Dependence 
• Increased blood pressure  
• Heart-related complications 
• Ongoing sleep problems 

Some people may begin to use decongestants for their stimulant effects (such as increased energy or focus), which can increase the risk of repeated or escalating use over time. 

Safety note 

Many cold and flu products contain decongestants along with other active ingredients. Taking multiple products at the same time can increase the risk of accidentally taking too much of one ingredient. 

Combining decongestants with other stimulants, such as caffeine or certain medications, can increase strain on the heart and raise the risk of side effects like anxiety, high blood pressure, or irregular heartbeat. 

Decongestants can also interact with some medications, including those for blood pressure, mental health, or attention-related conditions. 

Seek medical help if someone experiences chest pain, severe headache, or a racing or irregular heartbeat. 

Over-the-counter pain relievers are used to reduce pain and fever. Common types include acetaminophen (Tylenol) and nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen. 

Acetaminophen works by affecting pain signals in the brain and helping reduce fever. It is found in many common products, including cold and flu medicines, sleep aids, and combination pain relievers. 

When used as directed, these medications are generally safe and effective. 

Short- and Long-term effects  

Short-term effects  

At recommended doses, pain relievers can safely reduce pain and fever. 

Taking more than recommended can cause: 

• Feeling unwell or fatigued 
• Loss of appetite 
• Nausea or vomiting  
• Sweating  

In some cases, people may not notice serious symptoms right away, even after taking a harmful amount. 

Long-term effects 

Repeated misuse or taking high doses may lead to: 

• Increased risk of overdose (taking more than is safe to take) 
• Liver failure 
• Serious liver damage  

The liver processes acetaminophen, and high amounts can overwhelm the body’s ability to safely break it down. 

Many over-the-counter products contain acetaminophen. Taking more than one product at the same time (such as a pain reliever and a cold or flu medicine) can increase the risk of accidentally taking too much. 

Alcohol use or certain medications can also increase the risk of liver damage when combined with acetaminophen. 

Taking more than the recommended amount of acetaminophen can lead to an overdose, which can cause serious harm to the liver or lead to death. Early symptoms may be mild or easy to miss, but damage can continue over time. 

Getting medical care as soon as possible can make a difference. Seek medical help right away if someone may have taken more than the recommended amount, even if they feel okay. Signs of serious problems may include severe stomach pain, confusion, or yellowing of the skin or eyes. 

How are ibuprofen and naproxen different? 

Ibuprofen (Advil, Motrin) is a common over-the-counter pain reliever, but it affects the body differently than acetaminophen (Tylenol). While acetaminophen mainly impacts the liver, ibuprofen can irritate the stomach and affect the kidneys, especially at higher doses. 

Naproxen (Aleve) is also an over-the-counter pain reliever. It works in a similar way to ibuprofen and has similar risks, but it stays in the body longer, so its effects last longer. 

Taking too much ibuprofen or naproxen can lead to an overdose. Early symptoms may include stomach pain, nausea, or vomiting. In more serious cases, it can cause stomach bleeding, kidney problems, or trouble breathing. 

Like acetaminophen, it’s important to follow dosing instructions and be aware of how much you’re taking, especially when using more than one medication. 

Ibuprofen and other non-steroidal, anti-inflammatory medications are not recommended for people who are pregnant because they can impact fetal development. Acetaminophen (Tylenol) used as directed is a safe option for pain management. Always talk to your doctor to determine if medications are safe in pregnancy. 

Laxatives are used to relieve constipation. They work in different ways, such as softening stool, adding bulk, or stimulating bowel movements. 

They can be helpful for short-term use, but they are not meant to be used regularly unless recommended by a health care provider. 

The Laxative Myth 

Some people may use laxatives more often or in higher amounts than directed in an attempt to feel relief quickly or to manage weight, sometimes related to concerns about body image or eating disorders. The belief that laxatives are effective for weight control is a myth. Most food and calories are absorbed in the small intestine before laxatives act, so they do not prevent calorie absorption. 

Instead, laxative use may lead to the loss of water, minerals, electrolytes, and waste, not fat or calories. This can create temporary weight changes, but these effects do not last and can return once the body rehydrates. Misusing laxatives can also lead to dehydration and other serious health problems over time. 

Learn more about eating disorders and where to get help at the National Eating Disorder Association. 

Short- and Long-term effects  

Short-term effects 

At recommended doses, laxatives can help relieve constipation and support a bowel movement. 

Taking more than recommended or using them to manage weight can cause: 

• Cramping  
• Diarrhea  
• Dehydration  
• Lightheadedness or weakness  
• Loss of important minerals in the body (electrolyte imbalance)  

In some cases, people may not notice the full impact right away, but the body is still losing fluids and minerals. 

Long-term risks 

Repeated misuse or taking laxatives more often than directed may lead to: 

• Dependence (needing laxatives to have a bowel movement)  
• Ongoing constipation or digestive problems  
• Dehydration  
• Electrolyte imbalances, which can affect the heart and other organs 
• Kidney strain or damage  
• Reduced responsiveness of the digestive system over time  

The body can lose water and important minerals when laxatives are misused. Over time, this can disrupt how the digestive system and other organs function.

Safety note 

Using laxatives more often or in higher doses than recommended can disrupt the body’s natural digestive process. 

If constipation continues, a health care provider can help identify possible causes and safer, long-term options. 

Seek medical help if someone experiences severe dehydration, ongoing vomiting, weakness, or symptoms like dizziness or an irregular heartbeat. 

Yes. Taking large amounts of OTC medications can cause serious poisoning or overdose. 

Some overdoses happen when people take several products that contain the same ingredient. 

Most OTC medications are not meant to be addictive. However, some can still lead to misuse or unhealthy patterns when taken often or in high doses. 

High doses of certain medications, such as dextromethorphan (cough syrup) or diphenhydramine (Benadryl), can affect the brain and cause confusion, hallucinations, or dissociation.

Call 911 or seek emergency care if someone: 

• Has trouble breathing 
• Has seizures 
• Has severe confusion 
• Has chest pain or irregular heartbeat 
• Cannot be woken up 

You can also contact Poison Control at 1-800-222-1222 if you think someone has taken too much medication.