“Atarax (hydroxyzine) and Benadryl (diphenhydramine) were routinely administered in the chemotherapy I received for breast cancer. After 5 months of chemo, I attributed my loss of mental function to a condition I read about called “chemo brain” — and chalked it up as another price paid in side affects for the benefit of staying alive.Feb 6, 2023 · Benadryl is an over-the-counter antihistamine that contains the active ingredient diphenhydramine. People often use it to treat allergies. Because it causes drowsiness, some people take it as a ... May 19, 2022 · Yes, certain side effects are possible after using Benadryl long term. For example, long-term use of Benadryl may cause: an increased risk of dementia; withdrawal symptoms after the drug is stopped* However, keep in mind that doctors typically don’t recommend taking Benadryl as a long-term treatment. Giving Benadryl to dogs long term in some cases can be helpful for the dog. However, one of the main side effects of Benadryl is drowsiness. Giving too much dog Benadryl can cause the dog to go into a deep sleep for some time. Additionally, in some cases Benadryl can cause upset stomach and even possibly loss of appetite.Uses Diphenhydramine is an antihistamine used to relieve symptoms of allergy, hay fever, and the common cold. These symptoms include rash, itching, watery eyes, itchy eyes /nose/throat, cough,... Nov 15, 2017 · Asthma. Car Sickness. Insomnia. Motion sickness. Reactions to Vaccines. Because one of the common side effect of Benadryl in dogs is drowsiness, your vet may use it to alleviate dog anxiety, particularly associated with traveling and motion sickness that may occur during plane rides or car trips. Diphenhydramine, which is available as an over-the-counter medication, is a first-generation antihistamine that is used in a variety of conditions to treat and prevent dystonias, insomnia, pruritis, urticaria, vertigo, and motion sickness. It also possesses local anesthetic properties for those patients who have allergies to other, more commonly used local anesthetics; however, this is an off ...Jul 27, 2017 · Take one to two 50mg tablets at least 30 minutes prior to bedtime. The maximum dose of two tablets works best for sleep. You can take Dramamine with or without food, but make sure you take a dose with a full glass of water 1 2. Swallow tablets whole; don't crush or chew. Plan on taking Dramamine four to six hours prior to waking for the next ... Impaired concentration. Memory difficulties. Anxiety. Stomach disturbances. Nausea and vomiting. A dry mouth. Constipation. Liver problems, etc. In certain people, a paradoxical reaction to diphenhydramine is possible, meaning that the drug causes different symptoms than the intended ones.Jun 5, 2019 · The Major Antihistamine Effects of Diphenhydramine Prevents Histamine-Mediated: constriction of respiratory smooth muscle. rapid vasodilation in blood vessels. increased capillary permeability and subsequent edema. sensations of itching, pain, and “flare” formation. increase in heart rate and strength of contraction. One Benadryl per night seems to be enough to keep the ears dry & the resulting nausea at bay. I must admit that I'm not sure this is still even a problem for me. The last time I stopped to see if I still needed it was about 2 years ago. After 3 days, the dizziness/nausea/inner ear issues came back, so I promptly started taking the nightly ...Inhaled corticosteroids are often used daily as part of treatment for asthma caused or complicated by reactions to airborne allergy triggers (allergens). Side effects are generally minor and can include mouth and throat irritation and oral yeast infections. Some inhalers combine corticosteroids with long-acting bronchodilators.Aug 23, 2021 · Symptoms can be mild or serious and can include: skin rash. itchiness. flushing (temporary warmth, redness, or deepening of skin color) swelling under your skin, typically in your eyelids, lips, hands, or feet. swelling of your mouth, tongue, or throat, which can make it hard to breathe. “Atarax (hydroxyzine) and Benadryl (diphenhydramine) were routinely administered in the chemotherapy I received for breast cancer. After 5 months of chemo, I attributed my loss of mental function to a condition I read about called “chemo brain” — and chalked it up as another price paid in side affects for the benefit of staying alive.Sleep aids: The options. Sleep aids available without a prescription are widely available. Common choices and the potential side effects include: Diphenhydramine (Benadryl). Diphenhydramine is a sedating antihistamine. Side effects might include daytime drowsiness, dry mouth, constipation and urinary retention. Doxylamine (Unisom).Applies to diphenhydramine: compounding powder, injectable solution, oral capsule, oral disintegrating strip, oral liquid, oral tablet, oral tablet chewable, oral tablet disintegrating. General The most commonly reported side effects included somnolence, dizziness, and incoordination.Apr 6, 2023 · Dizziness. Feeling nervous and excitable. Not able to sleep. Feeling sleepy. These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https ... Giving Benadryl to dogs long term in some cases can be helpful for the dog. However, one of the main side effects of Benadryl is drowsiness. Giving too much dog Benadryl can cause the dog to go into a deep sleep for some time. Additionally, in some cases Benadryl can cause upset stomach and even possibly loss of appetite.While it may work to help you fall asleep for a few days, long-term use of Benadryl as a sleep-aid likely isn't effective and is associated with several side effects like next-day drowsiness. Additionally, the long-term use of drugs like Benadryl in those 65 years old and over is linked with an increased risk of dementia.Common Benadryl (diphenhydramine) side effects include drowsiness, dizziness, and blurry vision. Dry mouth and constipation are common, as well. Serious Benadryl side effects include a greater risk of falls — especially if you are an older adult — and potential long-term memory problems.and readily penetrates the blood-brain-barrier. Thus side effects such as grogginess, drowsiness, and memory loss are common. Diphenhydramine is also used for motion sickness and extrapyramidal symptoms in Parkinson’s disease patients. Potential harm to the brain: Long-term anticholinergic use has been associated with increased 1. McMillan JM, Aitken E, Holroyd-Leduc JM. Management of insomnia and long-term use of sedative- hypnotic drugs in older patients. CMAJ 2013;185:1499–505. [ PMC free article] [ PubMed] [ Google Scholar] 2. Gray SL, Anderson ML, Dublin S, et al. Cumulative use of strong anticholinergics and incident dementia: a prospective cohort study.Take one to two 50mg tablets at least 30 minutes prior to bedtime. The maximum dose of two tablets works best for sleep. You can take Dramamine with or without food, but make sure you take a dose with a full glass of water 1 2. Swallow tablets whole; don't crush or chew. Plan on taking Dramamine four to six hours prior to waking for the next ...Uses Diphenhydramine is an antihistamine used to relieve symptoms of allergy, hay fever, and the common cold. These symptoms include rash, itching, watery eyes, itchy eyes /nose/throat, cough,...Warnings What to ask your doctor Q&A Benadryl (diphenhydramine) is used for allergies and allergic reactions, as well as common cold symptoms. Benadryl can cause mild or serious side...Addiction and Misuse. Another cause of overdose is an addiction to Diphenhydramine. Patients can become addicted to Benadryl after taking it for an extended period or when it is used for recreational purposes. Side effects of Diphenhydramine overdose often cause long-term damage, which can be fatal to patients ingesting it.Side effects of antihistamines that make you drowsy can include: sleepiness (drowsiness) and reduced co-ordination, reaction speed and judgement – do not drive or use machinery after taking these antihistamines. dry mouth. blurred vision. difficulty peeing. Side effects of non-drowsy antihistamines can include: headache. Benadryl is a first-generation antihistamine, meaning it is one of the earlier drugs developed in this category of medications. First-generation antihistamines, like Benadryl, are often noted for their sedative side effects as they have the ability to travel to your brain (i.e. crosses the blood-brain barrier), which is why they can make you ...Higher dosage or long-term use of common drugs with anticholinergic effects is linked to significantly increased risk of dementia - including Alzheimer’s - says large study.Benadryl may cause serious side effects including: pounding heartbeats or fluttering in your chest, painful or difficult urination, little or no urination, confusion, lightheadedness, tightness in your neck or jaw, and. uncontrollable movements of your tongue. Get medical help right away, if you have any of the symptoms listed above.When corrected based on the number of drugs with anticholinergic effects an individual was taking, the odds ratio for cognitive impairment was 1.46 with a p value of .0181. However, overall the authors conclude that their data did not support the hypothesis that the use of anticholinergic medications increased the risk of alzheimer’s dementia ...May 8, 2019 · Answer. While Benadryl ( diphenhydramine) can safely be used once in a while as a sleep aid, long-term use is not recommended for multiple reasons. Even the intermittent use of Benadryl for sleep isn't generally recommended if you are elderly (over 65). Studies show that the elderly population doesn't metabolize Benadryl as quickly and are far ... Apr 8, 2023 · The main long-term side effects of Plaquenil are eye-related. ... To manage your symptoms, they may suggest an over-the-counter antihistamine you take by mouth, such as Benadryl (diphenhydramine ... Side Effects Of Benadryl. Overall, Benadryl is well tolerated and side effects are generally mild in severity. If they do occur, they should subside 4 to 6 hours after dosing, although this can be extended in those with kidney disease and in the elderly. Below, we discuss the most common side effects associated with Benadryl.Impaired concentration. Memory difficulties. Anxiety. Stomach disturbances. Nausea and vomiting. A dry mouth. Constipation. Liver problems, etc. In certain people, a paradoxical reaction to diphenhydramine is possible, meaning that the drug causes different symptoms than the intended ones.When corrected based on the number of drugs with anticholinergic effects an individual was taking, the odds ratio for cognitive impairment was 1.46 with a p value of .0181. However, overall the authors conclude that their data did not support the hypothesis that the use of anticholinergic medications increased the risk of alzheimer’s dementia ...Diphenhydramine, which is available as an over-the-counter medication, is a first-generation antihistamine that is used in a variety of conditions to treat and prevent dystonias, insomnia, pruritis, urticaria, vertigo, and motion sickness. It also possesses local anesthetic properties for those patients who have allergies to other, more commonly used local anesthetics; however, this is an off ...Apr 24, 2023 · Long-term use may also lead to harmful side effects. The inability to fall or stay asleep can have a significant, negative impact on your mood, productivity, and overall health. Insomnia can also ... “Atarax (hydroxyzine) and Benadryl (diphenhydramine) were routinely administered in the chemotherapy I received for breast cancer. After 5 months of chemo, I attributed my loss of mental function to a condition I read about called “chemo brain” — and chalked it up as another price paid in side affects for the benefit of staying alive.Diphenhydramine is a type of medicine called an antihistamine. It is used in some allergy and sleep medicines. Overdose occurs when someone takes more than the normal or recommended amount of this medicine. This can be by accident or on purpose. This article is for information only. DO NOT use it to treat or manage an actual overdose. Potential Kidney Risks. Yes, long-term use of Benadryl can put strain on the kidneys, as it can build up in the system. This can cause toxicity and potentially lead to kidney damage. It's important to be aware of the potential side effects of long-term use and to consult a doctor if any symptoms arise.Experts say skip antihistamines. Dana Benson. 713-798-8267. Houston, TX - Jun 28, 2021. Share this article. For people who take an antihistamine such as Benadryl for a cold or allergies, drowsiness is often a welcome side effect. But a Baylor College of Medicine sleep expert cautions against turning to this type of medication as a sleep aid.May 8, 2019 · Answer. While Benadryl ( diphenhydramine) can safely be used once in a while as a sleep aid, long-term use is not recommended for multiple reasons. Even the intermittent use of Benadryl for sleep isn't generally recommended if you are elderly (over 65). Studies show that the elderly population doesn't metabolize Benadryl as quickly and are far ... Pay attention to the side effects of Benadryl, especially if you’re an older adult. The body responds differently to Benadryl as you get older. And you may develop side effects that were never a problem before. Benadryl is not intended to be used as a daily, long-term medication for sleep or other issues.Nov 15, 2017 · Asthma. Car Sickness. Insomnia. Motion sickness. Reactions to Vaccines. Because one of the common side effect of Benadryl in dogs is drowsiness, your vet may use it to alleviate dog anxiety, particularly associated with traveling and motion sickness that may occur during plane rides or car trips. There is evidence that the use of diphenhydramine among older adults or the elderly may result in serious side effects. This holds true esp. if you are older than age 65. The older a person becomes, the greater the risk of adverse effects. Benadryl is listed as potentially Inappropriate Medication in Older Adults ( also known as Beers criteria)Diphenhydramine or : Benadryl (diphenhydramine) may cause sedation the next day (due to its long half-life), decreased alertness, diminished cognitive function, delirium, ... Read More. Created for people with ongoing healthcare needs but benefits everyone. Learn how we can help. 5k views Reviewed >2 years ago.First-generation antihistamines come with an increased risk of certain side effects and drug interactions, so they are not generally advised for long-term usage. “With first-generation antihistamines, some people note decreasing effectiveness if used daily for several days,” says Dr. Lin.Taking an over-the-counter sleep aid with diphenhydramine once in a while is generally not going to cause problems, other than a possible hangover the next day. Older people, however, can get confused when taking diphenhydramine because it also blocks a brain chemical called acetylcholine, which plays a big role in attention and short-term memory.Benadryl may cause serious side effects including: pounding heartbeats or fluttering in your chest, painful or difficult urination, little or no urination, confusion, lightheadedness, tightness in your neck or jaw, and. uncontrollable movements of your tongue. Get medical help right away, if you have any of the symptoms listed above.In the drug realm, antihistamines such as diphenhydramine (Benadryl), chlorpheniramine (Chlor-Trimeton), cetirizine (Zyrtec), and loratadine (Claritin) can help with a stuffy nose are safe for the heart. Nasal sprays deliver a decongestant right where you need it. In theory, this should minimize cardiovascular effects.Jan 24, 2018 · Taking an over-the-counter sleep aid with diphenhydramine once in a while is generally not going to cause problems, other than a possible hangover the next day. Older people, however, can get confused when taking diphenhydramine because it also blocks a brain chemical called acetylcholine, which plays a big role in attention and short-term memory. May 22, 2013 · When corrected based on the number of drugs with anticholinergic effects an individual was taking, the odds ratio for cognitive impairment was 1.46 with a p value of .0181. However, overall the authors conclude that their data did not support the hypothesis that the use of anticholinergic medications increased the risk of alzheimer’s dementia ... Common Side Effects of Diphenhydramine. Diphenhydramine is considered an H1 receptor antagonist, and it works by blocking the effect of histamine in the body. The chemical reactions that diphenhydramine trigger in the body can cause other potentially significant sedative side effects on the central nervous system (CNS).Jun 14, 2023 · The symptoms you have noticed are very likely the result of long-term heavy antihistamine use. Antihistamines tend to dry up the nose, which is why they are so effective in humans with allergic rhinitis, but the way they do that is by making the secretions thicker. In dogs, we are not worried much about a runny nose, but we are concerned about ... Besides having side effects including drowsiness, confusion, and urinary retention, a new study shows that frequent, long-term use of older antihistamines are associated with an increased risk of ...Diphenhydramine blocks the effects of histamine in your brain and this reduces symptoms. It enters the brain in large quantities and this can make you feel drowsy. Diphenhydramine also blocks the effects of another chemical called acetylcholine. This can help a cough or runny nose but can also cause side effects such as a dry mouth and dry nose.The active ingredient in Benadryl is called diphenhydramine. Like any medication, Benadryl has several side effects. Some of the most common are: feeling sleepy or drowsy. dry mouth or throat ...• Common side effects of montelukast include upper respiratory infection, fever, headache, sore throat, cough, stomach pain, diarrhea, earache or ear infection, flu, runny nose, and sinus infection.Long-term side effects Over-the-counter Benadryl is approved for temporary or short-term use and is not intended for long-term use. There is very little scientific research about the long-term ...Applies to diphenhydramine: compounding powder, injectable solution, oral capsule, oral disintegrating strip, oral liquid, oral tablet, oral tablet chewable, oral tablet disintegrating. General The most commonly reported side effects included somnolence, dizziness, and incoordination.Jan 24, 2018 · Taking an over-the-counter sleep aid with diphenhydramine once in a while is generally not going to cause problems, other than a possible hangover the next day. Older people, however, can get confused when taking diphenhydramine because it also blocks a brain chemical called acetylcholine, which plays a big role in attention and short-term memory. Jan 6, 2023 · Diphenhydramine is a common ingredient in sleeping aids; it is also used to treat allergies. While effective, the risk of serious diphenhydramine side effects—including confusion, dizziness, urinary retention, and liver or kidney issues—is increased in people age 65 and older. In the drug realm, antihistamines such as diphenhydramine (Benadryl), chlorpheniramine (Chlor-Trimeton), cetirizine (Zyrtec), and loratadine (Claritin) can help with a stuffy nose are safe for the heart. Nasal sprays deliver a decongestant right where you need it. In theory, this should minimize cardiovascular effects.Overdosing on diphenhydramine (Benadryl) can also lead to more serious side effects like severe confusion, seizures, low blood pressure, involuntary muscle spasms, hallucinations (seeing things that aren't there), and heart rhythm problems. In fact, the FDA released a warning to avoid high doses of diphenhydramine.Official answer. Diphenhydramine can be used as a short-term sleep aid to help ease occasional sleep problems. Older adults, children under age 16 and pregnant women should avoid taking diphenhydramine, as the risks to these groups may outweigh the benefits. Diphenhydramine should not be taken as a treatment for chronic insomnia.Besides having side effects including drowsiness, confusion, and urinary retention, a new study shows that frequent, long-term use of older antihistamines are associated with an increased risk of ...This video examines the question and remark: Benadryl long term side effects! I WISH I had KNOWN! Benadryl is a common OTC medication and is also known as D...Long term use of some antihistamines may increase your risk of dementia. Diphenhydramine (Benadryl®) blocks the effects of a neurotransmitter called acetylcholine. This neurotransmitter is vital for memory and learning. Diphenhydramine increased the risk of dementia by 54% in one 3,000 patient study followed for seven years.Jan 10, 2023 · hoarseness. lack or loss of strength. pain in the lower back or side. swelling of the hands, feet, or lower legs. trembling or shaking. Common side effects that do require medical attention ... It can sometimes cause a decrease in memory, confusion, and thinking issues. These side effects are more common in elders. In addition, taking Benadryl long-term might increase the risk of dementia. People aged> 65 who took medications such as Benadryl daily for over three years had an increased risk of dementia.Long-term side effects Over-the-counter Benadryl is approved for temporary or short-term use and is not intended for long-term use. There is very little scientific research about the long-term ...Oct 3, 2022 · Adults and children ≥12 years of age receiving conventional or orally disintegrating tablets: Headache, somnolence, fatigue, dry mouth. Fixed combination loratadine (the active ingredient contained in Claritin) pseudoephedrine sulfate preparations: Insomnia, dry mouth, headache, somnolence, nervousness, dizziness, fatigue. Pay attention to the side effects of Benadryl, especially if you’re an older adult. The body responds differently to Benadryl as you get older. And you may develop side effects that were never a problem before. Benadryl is not intended to be used as a daily, long-term medication for sleep or other issues.May 17, 2019 · Diphenhydramine, which is the active ingredient in ZzzQuil, can cause side effects in some people. The most common side effects of diphenhydramine include: drowsiness. dizziness. loss of ... Apr 8, 2023 · The main long-term side effects of Plaquenil are eye-related. ... To manage your symptoms, they may suggest an over-the-counter antihistamine you take by mouth, such as Benadryl (diphenhydramine ... Pay attention to the side effects of Benadryl, especially if you’re an older adult. The body responds differently to Benadryl as you get older. And you may develop side effects that were never a problem before. Benadryl is not intended to be used as a daily, long-term medication for sleep or other issues.Benadryl is a first-generation antihistamine, meaning it is one of the earlier drugs developed in this category of medications. First-generation antihistamines, like Benadryl, are often noted for their sedative side effects as they have the ability to travel to your brain (i.e. crosses the blood-brain barrier), which is why they can make you ...
Benadryl Addiction Side Effects. Despite having numerous benefits in the medical world, Benadryl has its share of negative side effects when abused. Some effects are short term whereas others can last a lifetime. A user can either encounter psychological effects, physical effects, or both. Some of the physical effects to watch out for include .... Rigby
Aug 1, 2023 · What are the side effects of Benadryl ... Diphenhydramine is only for short-term use until your symptoms clear up. ... (such as a long car ride, airplane or boat travel, amusement park rides, etc ... Jun 14, 2023 · The symptoms you have noticed are very likely the result of long-term heavy antihistamine use. Antihistamines tend to dry up the nose, which is why they are so effective in humans with allergic rhinitis, but the way they do that is by making the secretions thicker. In dogs, we are not worried much about a runny nose, but we are concerned about ... Jul 7, 2022 · Advertisement constipation. blurred vision. memory problems and dementia (especially in seniors) anxiety. dependence. What are the side effects of taking Benadryl every night? SIDE EFFECTS: Drowsiness, dizziness, constipation, stomach upset, blurred vision, or dry mouth/nose/throat may occur. If any of these effects persist or worsen, tell your doctor or pharmacistRead More → Jul 27, 2017 · Take one to two 50mg tablets at least 30 minutes prior to bedtime. The maximum dose of two tablets works best for sleep. You can take Dramamine with or without food, but make sure you take a dose with a full glass of water 1 2. Swallow tablets whole; don't crush or chew. Plan on taking Dramamine four to six hours prior to waking for the next ... Section snippets Sedation. The sedation associated with diphenhydramine is one of the most acknowledged effects of this medication. Indeed, it is frequently used as a medication to treat insomnia. 3 The sedative effect of diphenhydramine is related to its easy penetration of the blood-brain barrier. 4 In the brain, diphenhydramine interferes with H 1 receptors, which causes drowsiness and ...Jul 9, 2020 · This video examines the question and remark: Benadryl long term side effects! I WISH I had KNOWN! Benadryl is a common OTC medication and is also known as D... May 25, 2023 · Signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes. Not able to pass urine or change in how much urine is passed. A very bad skin reaction ( Stevens-Johnson syndrome / toxic epidermal necrolysis) may happen. Diphenhydramine blocks the effects of histamine in your brain and this reduces symptoms. It enters the brain in large quantities and this can make you feel drowsy. Diphenhydramine also blocks the effects of another chemical called acetylcholine. This can help a cough or runny nose but can also cause side effects such as a dry mouth and dry nose. Oct 3, 2022 · Applies to diphenhydramine: compounding powder, injectable solution, oral capsule, oral disintegrating strip, oral liquid, oral tablet, oral tablet chewable, oral tablet disintegrating. General The most commonly reported side effects included somnolence, dizziness, and incoordination. Diphenhydramine is a type of medicine called an antihistamine. It is used in some allergy and sleep medicines. Overdose occurs when someone takes more than the normal or recommended amount of this medicine. This can be by accident or on purpose. This article is for information only. DO NOT use it to treat or manage an actual overdose. Long-term use may also lead to harmful side effects. The inability to fall or stay asleep can have a significant, negative impact on your mood, productivity, and overall health. Insomnia can also ...Jun 8, 2022 · Sleep aids: The options. Sleep aids available without a prescription are widely available. Common choices and the potential side effects include: Diphenhydramine (Benadryl). Diphenhydramine is a sedating antihistamine. Side effects might include daytime drowsiness, dry mouth, constipation and urinary retention. Doxylamine (Unisom). Jul 27, 2017 · Take one to two 50mg tablets at least 30 minutes prior to bedtime. The maximum dose of two tablets works best for sleep. You can take Dramamine with or without food, but make sure you take a dose with a full glass of water 1 2. Swallow tablets whole; don't crush or chew. Plan on taking Dramamine four to six hours prior to waking for the next ... In the drug realm, antihistamines such as diphenhydramine (Benadryl), chlorpheniramine (Chlor-Trimeton), cetirizine (Zyrtec), and loratadine (Claritin) can help with a stuffy nose are safe for the heart. Nasal sprays deliver a decongestant right where you need it. In theory, this should minimize cardiovascular effects.Jun 15, 2016 · IV administration of 50 mg of DPH resulted in immediate improvement of tremor, rigidity, tachycardia, and eye versions. The patient was started on oral DPH 50 mg 4 times a day and the dose was reduced by 25% every 3 days. Oral clonidine 0.1 mg 3 times a day and a weekly 0.1 mg transdermal patch was added to mitigate sympathetic side effects. Dear Alice, I've experimented with the abuse of Benadryl on a few occasions now and have been absolutely blown off to another world, I was just curious as to what the side affects, long or short-term, can look like, and what the dangers are of abusing this drug (acetaminophen free).Apr 8, 2023 · The main long-term side effects of Plaquenil are eye-related. ... To manage your symptoms, they may suggest an over-the-counter antihistamine you take by mouth, such as Benadryl (diphenhydramine ... Side effects of antihistamines that make you drowsy can include: sleepiness (drowsiness) and reduced co-ordination, reaction speed and judgement – do not drive or use machinery after taking these antihistamines. dry mouth. blurred vision. difficulty peeing. Side effects of non-drowsy antihistamines can include: headache. Section snippets Sedation. The sedation associated with diphenhydramine is one of the most acknowledged effects of this medication. Indeed, it is frequently used as a medication to treat insomnia. 3 The sedative effect of diphenhydramine is related to its easy penetration of the blood-brain barrier. 4 In the brain, diphenhydramine interferes with H 1 receptors, which causes drowsiness and ....