Feb 18, 2010 · 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 ... Nov 24, 2022 · But it has quite a long list of possible side effects. In fact, the Canadian Society of Allergy and Clinical Immunology has given serious warnings about them, even for people. The organization issued a 2019 position statement about Benadryl. They advised against the drug because of the high risk of side effects and overdose. They said the drug ... 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. 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.Nov 14, 2022 · A 2017 study revealed that 10% of adults aged 18-45 use OTC sleep aids while 17.5% of people 65 years and older do. Most over-the-counter options are considered safe when used occasionally—as long as the medication is compatible with any medical conditions you have and other medications you take. But when taken night after night, trouble can ... The most common side effect is drowsiness, causing mild disorientation or dementia. An elderly person may fall asleep during normal activities. This sedating effect can cause unsteadiness. A person over 60 should get up slowly from a sitting or prone position to avoid fainting. If you take an anti-anxiety drug, it is not advisable to use ...Apr 8, 2022 · People who take too much Benadryl start to experience many of the medication’s side effects. These can include mild symptoms, such as dry mouth, constipation, and tiredness. Usually, the more Benadryl a person takes, the worse these side effects become. In more severe Benadryl overdose cases, symptoms like seizures, irregular heartbeats, and ... Aug 15, 2023 · 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. Benadryl can cause some children to be hyperactive. OTC cough and cold medicine should not be given to children under the age of 4. Research has shown that these products do not work in children younger than 6 years old and can have serious side effects.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.Benadryl is an antihistamine that can be used to treat allergic reactions, relieve motion sickness, as a sleep aid, and relieve some symptoms of Parkinson's disease. Sedation is a common side effect. 5. Tips. Benadryl may be taken with or without food. Take exactly as directed.Diphenhydramine is contraindicated in premature infants and neonates, as well as people who are breastfeeding. It is a pregnancy Category B drug. Diphenhydramine has additive effects with alcohol and other CNS depressants. Monoamine oxidase inhibitors prolong and intensify the anticholinergic effect of antihistamines. OverdoseDiphenhydramine 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. 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 ... “The antihistamine diphenhydramine is only approved for management of short-term or temporary sleep difficulties, particularly in those people who have problems falling asleep,” Dr. What are the negative effects of Benadryl? Drowsiness, dizziness, constipation, stomach upset, blurred vision, or dry mouth/nose/throat may occur. If any of ...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 ...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.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.Jun 23, 2009 · The most common side effect is drowsiness, causing mild disorientation or dementia. An elderly person may fall asleep during normal activities. This sedating effect can cause unsteadiness. A person over 60 should get up slowly from a sitting or prone position to avoid fainting. If you take an anti-anxiety drug, it is not advisable to use ... 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)Benadryl helps reduce the effects of natural chemicals in the body called histamines. It is used to treat the side effects of an allergic reaction, including: Benadryl can be taken to relieve the symptoms of hayfever (seasonal allergies) and motion sickness. It can also be taken to induce sleep and treat certain symptoms of Parkinson's disease.Long-term use of Benadryl can also lead to constipation and confusion. Interactions. Benadryl containing diphenhydramine can interact with alcohol as both are central nervous system (CNS) depressants. Side effects such as drowsiness and dizziness may be enhanced when taking alcohol with diphenhydramine.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 ... General The most commonly reported side effects included somnolence, dizziness, and incoordination. [ Ref] Nervous system Common (1% to 10%): Sedation/somnolence/sleepiness, drowsiness, unsteadiness, dizziness, headache, attention disturbance Rare (0.01% to 0.1%): Extrapyramidal effects, tremor, convulsionsApr 23, 2021 · Hives. Swelling and inflammation. Redness. Runny nose and eyes. Coughing. Sneezing. Anaphylactic reaction. One of the side effects of Benadryl is drowsiness, which can help to calm anxious dogs ... 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.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 ... May 13, 2021 · 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 ... 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.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. Long-term use of Benadryl can also lead to constipation and confusion. Interactions. Benadryl containing diphenhydramine can interact with alcohol as both are central nervous system (CNS) depressants. Side effects such as drowsiness and dizziness may be enhanced when taking alcohol with diphenhydramine.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, runny ...feeling of warmth, redness of the face, neck, arms and occasionally, upper chest. large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs. shortness of breath, difficult or labored breathing. Some side effects may occur that usually do not need medical attention.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.Yeah, look at r/dph.Datura is even worse. It's like dph, but way more likely to kill you or make you go blind. Shadow people and spiders and having full conversations with people who don't exist usually only happens in the 400+ category. Between 150mg and there, it's usually just having to piss but being unable to, dysphoria/fear, be Answer (1 of 2): Here is one long term study: “These drugs are called anticholinergics, among them the first-generation antihistamines that are now marketed as sleep aids.Long-Term Side Effects of Diphenhydramine Abuse. Continued diphenhydramine use can cause long-term adverse side effects that result in permanent damage. Not only will prolonged use cause harm, but it can lead to other aspects such as dependence on the medication. Common long-term side effects of prolonged diphenhydramine use include: Dependence. 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 ...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. Benadryl and Depression. Although there is no direct effect of Benadryl on depression, regular and daily use of Benadryl does result in severe depression in the individual. It is believed to be helpful only for the short term, however, long term use of Benadryl results in certain depressive symptoms in the individual.Nov 24, 2022 · But it has quite a long list of possible side effects. In fact, the Canadian Society of Allergy and Clinical Immunology has given serious warnings about them, even for people. The organization issued a 2019 position statement about Benadryl. They advised against the drug because of the high risk of side effects and overdose. They said the drug ... 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.Mar 21, 2023 · There is very little scientific research about the long-term effects of Benadryl. Some side effects that may occur with long-term use include: constipation; blurred vision 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 ...Benadryl helps reduce the effects of natural chemicals in the body called histamines. It is used to treat the side effects of an allergic reaction, including: Benadryl can be taken to relieve the symptoms of hayfever (seasonal allergies) and motion sickness. It can also be taken to induce sleep and treat certain symptoms of Parkinson's disease.Oct 9, 2018 · Many older adults may take sleeping pills because pain, nerve problems or other health issues are keeping them up at night, she says. For these people, a sleeping pill is standing in the way of ... 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).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 ... 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. 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.The most common side effect is drowsiness, causing mild disorientation or dementia. An elderly person may fall asleep during normal activities. This sedating effect can cause unsteadiness. A person over 60 should get up slowly from a sitting or prone position to avoid fainting. If you take an anti-anxiety drug, it is not advisable to use ...May 7, 2021 · 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) Benadryl can cause some children to be hyperactive. OTC cough and cold medicine should not be given to children under the age of 4. Research has shown that these products do not work in children younger than 6 years old and can have serious side effects.General The most commonly reported side effects included somnolence, dizziness, and incoordination. [ Ref] Nervous system Common (1% to 10%): Sedation/somnolence/sleepiness, drowsiness, unsteadiness, dizziness, headache, attention disturbance Rare (0.01% to 0.1%): Extrapyramidal effects, tremor, convulsionsApr 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 ... Aug 25, 2021 · Examples of Viagra’s more commonly reported side effects include: headache. flushing (temporary warmth, redness, or deepening of skin color) stuffy nose. indigestion (upset stomach) mild vision ... 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.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. Jul 9, 2015 · 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. Sep 14, 2022 · Benadryl helps reduce the effects of natural chemicals in the body called histamines. It is used to treat the side effects of an allergic reaction, including: Benadryl can be taken to relieve the symptoms of hayfever (seasonal allergies) and motion sickness. It can also be taken to induce sleep and treat certain symptoms of Parkinson's disease. Oct 9, 2018 · Many older adults may take sleeping pills because pain, nerve problems or other health issues are keeping them up at night, she says. For these people, a sleeping pill is standing in the way of ... Answer (1 of 2): Here is one long term study: “These drugs are called anticholinergics, among them the first-generation antihistamines that are now marketed as sleep aids.While there are cases of misuse and abuse, withdrawal symptoms from Benadryl are rare, even with long term use. Nevertheless, Benadryl has strong anticholinergic effects, and there have been reports of 'anticholinergic withdrawal' in some individuals taking Benadryl for extended periods of time. Potential symptoms include:General The most commonly reported side effects included somnolence, dizziness, and incoordination. [ Ref] Nervous system Common (1% to 10%): Sedation/somnolence/sleepiness, drowsiness, unsteadiness, dizziness, headache, attention disturbance Rare (0.01% to 0.1%): Extrapyramidal effects, tremor, convulsionsNov 15, 2019 · Central side effects. Since these actions are disrupted by sedating antihistamines, these drugs produce sedation, drowsiness, tiredness, lack of concentration, difficulty in learning and memory ... 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...• 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 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. 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 ...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.Apr 11, 2018 · 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 ... 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. 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.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 ...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,... There could be both short- and long-term consequences. Worried about the side effects of Ambien, Lunesta or other sleep aids? ... Diphenhydramine is an anticholinergic drug, which means it blocks ...Oct 9, 2018 · Many older adults may take sleeping pills because pain, nerve problems or other health issues are keeping them up at night, she says. For these people, a sleeping pill is standing in the way of ... General The most commonly reported side effects included somnolence, dizziness, and incoordination. [ Ref] Nervous system Common (1% to 10%): Sedation/somnolence/sleepiness, drowsiness, unsteadiness, dizziness, headache, attention disturbance Rare (0.01% to 0.1%): Extrapyramidal effects, tremor, convulsionsBenadryl 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 ...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.Dec 1, 2022 · 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 ... 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.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.• 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.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. 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 ... There could be both short- and long-term consequences. Worried about the side effects of Ambien, Lunesta or other sleep aids? ... Diphenhydramine is an anticholinergic drug, which means it blocks ...Feb 18, 2010 · 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 ...
Apr 11, 2023 · 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. . How to get someone
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 ...feeling of warmth, redness of the face, neck, arms and occasionally, upper chest. large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs. shortness of breath, difficult or labored breathing. Some side effects may occur that usually do not need medical attention.Jul 9, 2015 · 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. 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. General The most commonly reported side effects included somnolence, dizziness, and incoordination. [ Ref] Nervous system Common (1% to 10%): Sedation/somnolence/sleepiness, drowsiness, unsteadiness, dizziness, headache, attention disturbance Rare (0.01% to 0.1%): Extrapyramidal effects, tremor, convulsionsSection 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 ...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.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.Effects of Long-Term Diphenhydramine Use The information regarding the effects of prolonged Benadryl use is once again not known, as prospective studies analyzing its prolonged use do not exist. There are some exceptions to the above statement, however, the following are related to the long-term use of any antihistamine medication and ...Long-Term Side Effects of Diphenhydramine Abuse. Continued diphenhydramine use can cause long-term adverse side effects that result in permanent damage. Not only will prolonged use cause harm, but it can lead to other aspects such as dependence on the medication. Common long-term side effects of prolonged diphenhydramine use include: Dependence. Jul 9, 2015 · 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. 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..