Is Benadryl (Diphenhydramine) Addictive?

Medically reviewed by

David Hunter, MA.Ed, LPC

January 23, 2019

What Is Benadryl?

Benadryl or diphenhydramine is the most widely used OTC antihistamine and is available in a tablet, capsule, or liquid form. It is most commonly used to treat the symptoms of allergies, the common cold, or hay fever and as a sleep aid. In some circumstances, it is used to treat motion sickness, specifically to alleviate nausea, vomiting, and dizziness. It may also be used to treat the medically induced symptoms of Parkinson’s or to treat drug-induced movement disorders called Extrapyramidal Symptoms (EPS).

Diphenhydramine works by blocking the production of histamines which are produced when your body encounters an allergic reaction. It also blocks the response of the neurotransmitter acetylcholine which results in the sedative properties of the drug. The National Highway Traffic Safety Administration classifies it as a central nervous system (CNS) depressant.

Diphenhydramine Interactions and Precautions

One of the most notable side-effects of diphenhydramine is drowsiness and sedation and for that reason, special care needs to be taken. This is especially true when this drug is taken in conjunction with other substances that also cause impair the CNS or cause drowsiness, including antihistamines; sleep or anxiety medicines, such as benzodiazepines; muscle relaxants; and opiates. Make sure to inform your doctor if you currently take any medications within these classes.

It can also interfere with people with certain conditions or diseases, such as asthma; some mood disorders; hyperthyroidism; cardiovascular disease; kidney problems; glaucoma; and an enlarged prostate gland. Some diphenhydramine preparations may contain sugar, aspartame, or alcohol and it is advisable for those that have liver disease, diabetes, phenylketonuria (PKU), or any other health concern to proceed with taking these substances only under the supervision of a physician.

Can You Get Addicted To Diphenhydramine?

The short answer is no, but diphenhydramine can easily be abused. Using antihistamines beyond their created intent is substance abuse. Those that take amounts greater than the recommended dosage may develop a tolerance.

This does not mean you are addicted in the scientific sense. Instead, some people may develop psychological dependence and this becomes apparent when the individual becomes overwhelmed with the desire to use. This is called a craving, a dangerous need that overwhelms the individual and compels them to use in spite of the knowledge that using the drug can cause harm.

It is these two things, physical and psychological dependence, that can create what some people consider to be a diphenhydramine addiction. This misuse should not be taken lightly. As with chemical dependencies, it needs to be treated seriously and immediately to ensure that the individual can receive the help and treatment they need.

What Constitutes Diphenhydramine Abuse?

The National Institute on Drug Abuse (NIDA) states that “it becomes drug abuse when people use illegal drugs or use legal drugs inappropriately. This includes the repeated use of drugs to produce pleasure, alleviate stress, and/or alter or avoid reality.” Some people seek to misuse OTC drugs in a manner that creates an effect on the body and mind that may, in part, mimic or enhance illicit drug use.

The Southern Medical Journal (SMJ) reported that “anticholinergics are abused for the stimulant, euphoriant, and hallucinogenic effects they can produce when taken in large doses, with the most frequent reason for abuse given by patients being ‘to get high.’”

The article goes on to discuss the stimulating properties that some experience, stating that “antihistamine abuse appears to be targeted at sedation resulting from H1 receptor antagonism; however, antihistamines also may affect dopaminergic transmission, resulting in a cocaine-like effect.”

A rising amount of people abuse antihistamines like diphenhydramine. This is due, largely in part to their relatively cheap price and availability. For those that abuse diphenhydramine, they are commonly seeking the sedative or euphoric qualities. Some people find this state relaxing and seek the reduction in anxiety that may be accompanied by antihistamine use.

Additionally, some people seek drowsiness and sleep and as they begin taking the diphenhydramine in increasing dosages, they gain a higher tolerance. This increases the risk of dependence and physical and mental risks.

Risks Of Diphenhydramine Abuse

Diphenhydramine is not meant to be taken over an extended period of time. It is important to realize that while some people may experience some of these symptoms with the recommended dose, those that misuse the drug run the risk of increasing the severity of these symptoms:

• Sedation
• Impaired coordination or vertigo
• Tinnitus
• Blurred or double vision
• Increased heart rate or heart palpitations
• Irritability or confusion
• Impaired concentration and memory
• Increased anxiety
• Stomach disturbances or constipation
• Nausea accompanied by a decreased appetite
• Xerostomia or dry mouth that can increase the risk of cavities and gastroesophageal reflux disease (GERD)
• Low blood pressure
• Seizure
• Liver dysfunction (if used concurrently with alcohol)

Some people may have a paradoxical reaction to diphenhydramine, meaning the drug may actually cause the opposite symptoms of what’s intended.

There is also evidence to suggest that prolonged use of anticholinergics, including diphenhydramine, may increase the risk of dementia including Alzheimer’s disease. Dr. Shelly Gray, a study author of Cumulative Use of Strong Anticholinergic Medications and Incident Dementia stated “we know that these medications may have an effect on memory, and we always assumed that these effects were reversible. We didn’t think these medications were changing the brain permanently. Our study does suggest a link between the highest use and increased dementia risk.”

Mixing Diphenhydramine With Other Drugs

Sometimes people intentionally pair diphenhydramine with the substances that have adverse reactions with it, including alcohol, MAOI’s, benzodiazepines, muscle relaxants, and some opiates. In fact, in many cases, it is these reactions that the user seeks.

As with any poly-drug use, mixing one or more substances can result in potentially harmful and dangerous results and in the worst case scenario, death is possible.

Risks Of Overdose

With any drug, even an OTC, there is a risk of overdose. SMJ also reports that “from 2004 to 2011, many non-controlled medications showed significant increases in such ED visits; for example, visits caused by diphenhydramine use increased from 10,457 to 19,012 (82%).”

Overdose symptoms may include:

• Severe drowsiness
• Seizures
• Widened pupils
• Trouble breathing
• Irregular heartbeat

If you see these symptoms or fear the possibility of an overdose, seek medical attention immediately. This risk markedly increases with the concurrent use of other drugs. If you experience any complications or symptoms of overdose while using more than one drug, it is imperative that you inform the medical staff of any drugs you are using.

Treating Diphenhydramine Abuse

For people using elevated amounts of diphenhydramine, some physicians suggest that the best way to stop is by tapering the dose over a 1-2 week period. The exact time frame varies depending on the individual, the duration of use, and the amount consumed.

If you find that you or someone you know is abusing diphenhydramine, we recommend speaking to a physician to discuss your sleep patterns, anxiety, or any other issues that fuel your use. If you are also dealing with physical or mental health concerns, such as insomnia, depression, anxiety, or other mood disorder—we recommend that you also treat these to obtain the greatest benefits.

We’re Here To Help

As with any substance abuse, we urge you to seek professional help. This can be the difference between struggling through unhealthy patterns of abuse or achieving a successful recovery. If you are concerned about yourself or a loved one—please contact us today. The highly trained and caring staff at RehabCenter.net are more than happy to answer any of your questions.