The Effects of Benadryl

Legacy Healing Center Blog

Benadryl is a popular over-the-counter medication that relieves symptoms associated with allergies, colds, and other conditions. While it can be effective, it’s also vital to understand the risks of taking it too often or in large doses. Legacy Healing Center offers resources to help people make safe medication choices.

How Does Benadryl Work?

Benadryl works by blocking histamine receptors in the body. The immune system releases histamine during allergic reactions, and it causes symptoms such as swelling, itching, and inflammation. By blocking these receptors, Benadryl helps reduce or prevent these allergic responses.

How long does it take for Benadryl to kick in?

Benadryl starts to work within 30 minutes after taking it. The full effects of the medication are usually felt within 1 to 2 hours of taking it.

How long do the effects of Benadryl last?

Typically, its effects last 4 to 6 hours, depending on the individual, though the sedative effects (drowsiness) may wear off sooner for some individuals.

How long does Benadryl stay in your system?

While you might stop feeling its effects after a few hours, Benadryl can stay in your system for 24-48 hours, with traces detectable for a few days after a single dose. However, factors like metabolism, age, and health conditions can affect how long it stays active.

How long is Benadryl detectable in drug tests?

Urine: Benadryl is typically detectable in urine for 1 to 3 days after use.
Blood: It is detectable in blood for about 24 hours.
Saliva: It may be detectable for 1 to 2 days.
Hair: In rare cases, it may be detectable in hair follicles for up to 90 days, though this is not a standard method for testing.

Side Effects of Benadryl

While Benadryl is effective for allergy symptom relief, it can cause several side effects, especially when used in higher doses or for extended periods:

Drowsiness: One of the most common side effects of Benadryl is sedation, which is why it’s often used as a sleep aid.
Dizziness and confusion: Older adults are especially prone to confusion, dizziness, or falls when taking Benadryl.
Dry mouth, throat, or nose: Benadryl can cause dryness of the mouth and throat.
Blurred vision: Benadryl can cause difficulty focusing or blurry vision in some people, especially older adults.
Urinary retention: It may cause difficulty urinating in some individuals, especially older adults.

How Much Benadryl Is Safe to Take?

Following the recommended dosage is essential for safety. Taking more than recommended can lead to severe side effects, including confusion, blurred vision, dry mouth, or even heart issues.

Adult Dosage (for allergy relief, cold symptoms, and other uses): For adults, the recommended dose of Benadryl for allergy relief or cold symptoms is typically 25 to 50 mg every 4 to 6 hours. The maximum dose should not exceed 300 mg per day (6 doses of 50 mg).
Dosage for Sleep Aid: When used as a sleep aid, the typical dose for adults is 50 mg, taken 30 minutes before bedtime.
- However, this should only be used for short periods, as Benadryl can cause tolerance, and it’s not recommended as a long-term solution for insomnia.
Children’s Dosage: The usual dose for children between the ages of 6 and 12 is 12.5 to 25 mg every 4 to 6 hours, with a maximum of 150 mg per day. The dose for children aged 2 to 6 is usually 6.25 mg every 4 to 6 hours, with a maximum of 37.5 mg per day.

Important Note: Benadryl is not recommended for children under 2 years old. In infants and toddlers, an overdose can lead to serious complications, including seizures and death.

What happens if you take too much Benadryl?

If someone takes an extremely high dose, it can lead to serious complications, including seizures, coma, or even death in rare cases. Knowing the safe dosage can help prevent misuse and potential harm.

Can Benadryl Get You High?

Yes, Benadryl (diphenhydramine) can produce feelings of euphoria or a “high” when taken in large doses, but it is extremely dangerous and not recommended for this purpose. Diphenhydramine, the active ingredient in Benadryl, is an antihistamine that blocks the effects of histamine in the body. At normal doses, it works to relieve allergy symptoms, but in high doses, it also has sedative and hallucinogenic effects.

When taken in larger-than-recommended doses, diphenhydramine can cause drowsiness, confusion, delirium, hallucinations, and euphoria. These effects may make the user feel “high” or detached from reality, which can be dangerous. Legacy Healing Center provides the necessary addiction treatment, therapy, and counseling to help individuals struggling with Benadryl misuse or dependency, offering a structured and safe environment for recovery.

Other Health Effects of Benadryl

Using Benadryl occasionally is usually safe, but long-term or high-dose use can impact health.

Hallucinations and Delirium: At high doses, Benadryl can cause delirium, which may involve confusion, agitation, and vivid hallucinations. These sensations can be frightening and unpredictable, potentially leading to dangerous behavior.
Risk of Overdose: Overdosing on Benadryl can result in severe consequences, including seizures, difficulty breathing, heart problems, extreme sedation or coma, and in extreme cases, death.
Cognitive Impairment: High doses of Benadryl can significantly impair cognitive functions, leading to problems with memory, concentration, and thinking. This impairment is especially dangerous for people with underlying health issues or those who need to be alert.
Anticholinergic Toxicity: At high doses, diphenhydramine can cause anticholinergic toxicity, leading to symptoms like dry mouth, blurred vision, rapid heart rate, urinary retention, and fever
Risk of Addiction: Though Benadryl is not classified as a drug of abuse in the same way as opioids or stimulants, repeated misuse can lead to psychological dependence. People may become accustomed to the sedative or hallucinogenic effects, which could lead them to use it more frequently or in higher doses.
Dangerous Interactions: Taking Benadryl in large amounts, especially when combined with other substances (like alcohol or sedatives), can increase the risk of overdose, respiratory depression, and other life-threatening effects.

Benadryl Withdrawal

Those using Benadryl regularly or in larger doses who decide to stop suddenly may notice Benadryl withdrawal symptoms like restlessness, irritability, insomnia, and anxiety. Since Benadryl is an antihistamine with sedative properties, quitting abruptly after prolonged use can lead to heightened emotional distress or sleep disturbances.

In some cases, individuals may also have difficulty concentrating or feel physically unwell. Withdrawal from Benadryl is generally less severe than opioid or alcohol withdrawal, but it’s still important to seek medical advice if someone is struggling with dependence or withdrawal symptoms.

While medical detox is generally not required for Benadryl withdrawal, there are other reasons why medical detox may be considered:

Severe or prolonged misuse: If someone has been taking large doses of Benadryl over an extended period, they may experience more intense withdrawal symptoms like confusion, delirium, tremors, or psychological distress.
Co-occurring substance use: If Benadryl misuse is combined with other substances (such as alcohol or other sedatives), a medical detox program may be necessary to monitor and manage potential complications and interactions.
Pre-existing health conditions: People with underlying medical conditions, such as liver or kidney issues, may require closer monitoring during withdrawal to ensure their safety.

Support at Legacy Healing Center

If you or someone you know is struggling with Benadryl misuse or any other substance, Legacy Healing Center is here to help. With addiction therapy programs and resources available across the country, our addiction rehab centers are ready to provide the guidance and support you need to make safe choices and lead a healthier life. Reach out today to learn more about our drug and alcohol treatment options. Feel free to also read our recovery articles for more insight into substance abuse, treatment, and more.