Antihistamine addiction: symptoms, side effects, withdrawal, and treatment

Antihistamine addiction is the excessive and obsessive use of drugs intended to counteract the effects of histamine in the body. Usually used to treat allergy symptoms, antihistamines contain sedative properties. Addiction occurs when individuals engage in persistent and compulsive use of antihistamines, often exceeding recommended dosages, in pursuit of the pleasurable or calming sensations these medications provide.

The symptoms of antihistamine addiction include drowsiness, increased tolerance, mood swings, depression, preoccupation with medication, and experiencing withdrawal symptoms. 

The side effects of antihistamine addiction are dry mouth, drowsiness, nausea, difficult or painful urination, headache, fatigue, and cognitive impairment. 

The symptoms of antihistamine withdrawal include intense itching, heightened anxiety, insomnia, nausea, vomiting, headaches, sweating, and confusion.

Available treatments for antihistamine addiction are detoxification, cognitive behavioral therapy (CBT), support groups, and counseling.

What is Antihistamine addiction?

Antihistamine addiction describes a problematic pattern of use in which people become dependent on antihistamine drugs, usually in excess of the recommended dosage and duration. It is the obsessive and chronic abuse of over-the-counter allergy medications, which are intended to treat allergy symptoms by lessening the body’s reaction to histamine.

While these medications serve a legitimate purpose in managing allergic reactions, their sedative effects are likely to be abused when individuals exceed recommended doses, seeking to achieve a heightened state of relaxation or drowsiness. 

The abuse of antihistamines goes beyond their intended use, as individuals continue to consume these drugs excessively, driven by a perceived need for the sedative effects rather than addressing allergy symptoms appropriately.

How common is Antihistamine addiction?

Antihistamine addiction is common, as 13,574 (14.7%) of the 92,033 overdose fatalities that occurred in 2019–2020 were antihistamine-positive, while 3,345 (3.6%) were antihistamine-involved, according to the Centers for Disease Control and Prevention (CDC)’s Morbidity and Mortality Weekly Report (MMWR) published in October 2022. 

The report further stated that antihistamines alone accounted for 90 (less than 0.1%) of deaths. First-generation H1 antihistamines, predominantly diphenhydramine, were implicated in the majority of antihistamine-positive and associated fatalities.

Why is using Antihistamines addictive?

Using antihistamines is addictive because of their sedative effects. Administering these medications lessens the body’s reaction to histamine, which in turn reduces allergy symptoms. However, their sedative properties tend to be appealing to individuals seeking relaxation or drowsiness, leading to misuse. 

The addictive nature arises as users develop a psychological dependency on the calming sensations produced by these medications. Over time, affected individuals engage in compulsive and excessive use, exceeding recommended doses to achieve the desired effects. 

This pattern of misuse, driven by the pursuit of the sedative qualities rather than addressing legitimate allergy symptoms, contributes to the development of antihistamine addiction.

What are the most commonly abused Antihistamines?

The most commonly abused antihistamines include anti-allergy medications, often over-the-counter, that individuals misuse or overuse for non-medical purposes. The most commonly abused antihistamines are listed below. 

• Benadryl: Benadryl is commonly abused due to its sedative effects, which induce feelings of relaxation and drowsiness. While Benadryl, whose active ingredient is diphenhydramine, is often utilized to alleviate symptoms such as sneezing, runny nose, itching, and watery eyes caused by various allergens, certain people are drawn to the calming sensations produced by the medication. This allure to Benadryl’s sedative characteristics leads to overuse, with people taking large doses of the medicine to get the desired effects. It is via this practice of misuse that Benadryl addiction develops. The accessibility of the medicine without a prescription makes it easier for people to misuse it, since they fail to consider the potential dangers of consuming too much of the medication. 
• Zyrtec: Zyrtec (cetirizine) is a drug used to treat urticaria and allergic rhinitis, according to a continuing education activity by Aasim Naqvi and Valerie Gerriets last updated in January 2023 by StatPearls. It belongs to the class of second-generation antihistamines. Cetirizine is a rapid-acting, highly specific antagonist of the peripheral histamine H1 receptor. It has significantly lower sedative effects in comparison to other first-generation antihistamines, such as diphenhydramine and doxylamine. Although generally considered safe when taken as directed, when recommended dosage and guidelines are not observed, the onset of misuse patterns of Zyrtec is a possibility. 
• Allegra: Allegra (fexofenadine) is classified as a second-generation antihistamine. A continuing education activity titled, “Fexofenadine” last updated in December 2022 by StatPearls stated that the United States Food and Drug Administration (FDA) has approved its use for treating both chronic idiopathic urticaria and seasonal allergic rhinitis. Fexofenadine affects various bodily systems by selectively blocking H1 receptors on cell surfaces. Unlike other H1 blockers, fexofenadine does not induce drowsiness because it passes the blood-brain barrier to a lesser level than other first-generation antihistamines. It has the potential for misuse if individuals deviate from recommended dosages or use it for unintended purposes. In certain situations, people incorrectly believe that taking more of the medication will enhance its effectiveness, but this leads to adverse effects.

What are the symptoms of Antihistamine addiction?

Symptoms of antihistamine addiction refer to observable signs or behaviors indicative of a person’s dependency or misuse of antihistamine medications. The symptoms of antihistamine addiction are listed below. 

• Drowsiness: Drowsiness is a classic sign of antihistamine addiction because these medications inhibit histamine receptors in the brain, producing a relaxing effect and drowsiness particularly at larger doses. People find it difficult to stay vigilant as a result, which raises the possibility of accidents and lowers the level of productivity.
• Increased tolerance: Antihistamine addiction often involves the development of tolerance, where individuals require higher doses to achieve the desired sedative effects like drowsiness. This behavior suggests that the body has adapted to the drug, and as a result, users notice that the first effective dose becomes ineffective, resulting in a dangerous loop of increasing consumption. 
• Mood swings: Mood swings range from irritability to periods of low mood or depression. The individual’s mental and emotional stability is greatly affected by these mood fluctuations, which are a sign of the physiological dependence that has evolved from chronic usage of antihistamines. According to a study by Ozdemir et al., published in the 2014 issue of the International Journal of Psychiatry in Clinical Practice, the antihistamines cetirizine and hydroxyzine were found to have detrimental effects on mood states.
• Depression: The combination of the medication’s central nervous system effects and the psychological consequences of addiction worsens symptoms of depression. This leads to a cycle where the individual relies on the antihistamine to alleviate emotional distress, perpetuating the addiction.
• Preoccupation with medication: People struggling with antihistamine addiction constantly think about obtaining and using the medication, leading to a preoccupation that interferes with daily activities and responsibilities. This preoccupation contributes to a compulsive need to procure and use the antihistamine, even when it is not medically necessary, indicating a loss of control over one’s drug use behavior.
• Experiencing withdrawal symptoms: When individuals attempt to reduce or stop their antihistamine use, withdrawal symptoms emerge as the body and brain adjust to the absence of the drug. These withdrawal symptoms include heightened anxiety, itching, insomnia, sweating, mood swings, and other discomforts. A significant indication of dependence on the drug and the emergence of an addictive pattern is the occurrence of withdrawal symptoms.

What are the side effects of Antihistamine addiction?

Side effects of antihistamine addiction manifest across physical, psychological, and behavioral domains. The side effects of antihistamine addiction are listed below. 

• Dry mouth: Antihistamines cause dry mouth through their anticholinergic effects. Anticholinergic drugs work by blocking the action of acetylcholine, a neurotransmitter that mediates various bodily functions, including saliva production. Prolonged use worsens dry mouth symptoms, making it harder to speak, swallow, and practice proper oral hygiene.
• Drowsiness: One of the most prevalent adverse effects of antihistamines is drowsiness, according to a 2019 study by Jonas Dyhrfjeld-Johnsen and Pierre Attali published in the British Journal of Clinical Pharmacology. To mitigate allergy symptoms, antihistamines function by suppressing histamine’s effects. However, the same process that relieves allergy symptoms affects other neurotransmitters, including acetylcholine, which promotes alertness. Antihistamines provide a drowsy, sedative effect by inhibiting histamine and interfering with acetylcholine.
• Nausea: Although histamine receptor blocking is the primary target of these drugs, they additionally interact with other receptors, especially those associated with the gastrointestinal tract. This causes a disturbance in the gastrointestinal tract’s usual regulatory systems, which leads to nausea.
• Difficult or painful urination: Since antihistamines are anticholinergic, they block the action of acetylcholine, a neurotransmitter that is involved in several body processes, including the contraction of muscles during urination. Disruption of the normal cholinergic activity leads to urinary retention or difficulties in voiding, potentially causing discomfort or pain during urination.
• Headache: Antihistamines affect the central nervous system in a way that causes blood vessels in the brain to narrow and alter blood flow, which leads to headaches. In fact, in a 2021 case report by Assadi et al., published in the Case Reports in Acute Medicine, a 38 year-old woman complained of excruciating headaches that she had on a regular basis. The diagnosis of RCVS was validated by brain imaging using Magnetic Resonance Angiography (MRA). Reversible cerebral artery vasoconstriction, or RCVS, is typified by abrupt, severe headaches. In this instance, the only notable change in the patient’s history before symptoms appeared was the use of the antihistamine loratadine. This suggests the possibility of a causative link between antihistamine use and the development of RCVS.
• Fatigue: Antihistamines, particularly the older generation ones, often possess sedative properties, crossing the blood-brain barrier and interacting with receptors that control wakefulness. As a result of this interaction, attentiveness is diminished and drowsiness increases, both of which contribute to feelings of fatigue. Moreover, the sedative properties cause disruptions in the regular sleep-wake cycle, resulting in sleep pattern disturbances and exacerbating daytime fatigue.
• Cognitive impairment: Certain antihistamines, particularly those with strong anticholinergic properties, have been associated with cognitive impairment. For instance, a 2020 study by Georg Adler and Nadja Baumgart published in the journal Alzheimer’s & Dementia found that individuals receiving second or third-generation antihistamines had significantly worse episodic working memory than patients not receiving antihistamine therapy. Regardless of whether antihistamines were taken at higher or lower levels, this impairment was especially noticeable in older participants.

Can you overdose on Antihistamines?

Yes, you can overdose on antihistamines, and such incidents have major implications. An antihistamine overdose is when a person takes more medication than is recommended for therapeutic benefit, which has undesirable consequences and is possibly harmful. 

Symptoms of antihistamine overdose vary in severity and include drowsiness, confusion, blurred vision, dry mouth, and urinary retention. Excessive ingestion of antihistamines, especially those with sedative effects, lead to an intensification of their central nervous system depressant properties. Severe cases involve more pronounced symptoms such as hallucinations, seizures, and, in extreme instances, respiratory depression and coma.

The severity of the overdose depends on the specific antihistamine, the amount ingested, and individual factors. It’s crucial to adhere to the recommended dosage guidelines and seek immediate medical attention if there are concerns about a potential drug overdose.

What are the risk factors for Antihistamine addiction?

Risk factors for antihistamine addiction encompass various elements that increase the likelihood of individuals developing a dependency on these medications. The risk factors for antihistamine addiction are listed below. 

• History of substance abuse or addiction: Individuals with a history of substance abuse or addiction are at an elevated risk of antihistamine addiction. A predisposition to addictive behaviors make these individuals more susceptible to misusing antihistamines for their sedative effects.
• Self-medication: Individuals experiencing medical problems for which antihistamines are often recommended are likely to misuse them to self-medicate in order to seek relief from symptoms associated with such conditions. A study by Jindal et al., published in the January 2019 issue of the National Journal of Physiology, Pharmacy and Pharmacology found that 90% of the participants (200 out of 220 questionnaires examined) used antihistaminics for self-medication. The most frequent reasons people took antihistamines to self-medicate were bug bites (6%), motion sickness (7%), urticaria (14%), sinusitis (34%), and allergic rhinitis (39%). The main justifications for self-medication were urgency, cost-effectiveness, time-saving, and mild illness.
• Social factors: Social factors, including a lack of social support or exposure to an environment where substance misuse is prevalent, contribute to the risk of antihistamine addiction. Individuals in socially isolated or unsupportive environments are likely to misuse antihistamines for various reasons, including coping with stress or fitting into social norms.
• Age: Certain demographic factors, such as being in the adolescent or young adult age group, potentially increase the susceptibility to antihistamine addiction. Adolescents and young adults are more prone to experimentation and risky behaviors, including the misuse of medications. A 2021 study by Schifano et al., published in Frontiers in Psychiatry revealed that OTC pharmaceuticals that are most commonly diverted and misused are decongestants, cough/cold remedies, and antihistamines. Adolescents and young adults are especially susceptible to these types of drug misuse.

What are the symptoms of Antihistamine withdrawal?

The symptoms of antihistamine withdrawal include intense itching, heightened anxiety, insomnia, nausea, vomiting, headaches, sweating, and confusion. According to a 2018 publication titled, “Deprescribing Guide for Sedating Antihistamines” published by The New South Wales Therapeutic Advisory Group Inc., withdrawal symptoms are typically mild and highly variable, and may persist for six to eight weeks. 

Antihistamine withdrawal symptoms manifest as individuals attempt to reduce or stop their use of these medications. They emphasize how crucial it is to gradually reduce dosage under medical supervision in order to reduce discomfort and provide a more seamless transition.

What are the available treatments for Antihistamine addiction?

Available treatments for antihistamine addiction involve a multifaceted strategy that takes into account the behavioral, psychological, and physical aspects of the addiction. The available treatments for antihistamine addiction are listed below. 

• Detoxification: Treatment for antihistamine addiction involves detoxification, which is the monitored removal of the drug from the body. Medical personnel monitor the detox process to guarantee safety and provide assistance in managing withdrawal symptoms. A study by Thomas et al., published in the 2009 issue of the Journal of Psychopharmacology featured a case investigation of GF, a 56-year-old woman who had been diagnosed with schizophrenia for 20 years. She was brought to an inpatient addictions unit in order to undergo detoxification due to diphenhydramine (DPH) abuse. After receiving treatment according to a plan of gradually reducing doses, GF finished the detoxification regimen with relative ease. At six months, she had not relapsed and had been released from the inpatient detoxification program as scheduled.
• Cognitive behavioral therapy (CBT): This evidence-based strategy tries to find and change the thought patterns and behaviors that lead to antihistamine addiction. CBT helps people learn healthier ways to deal with problems and addresses the root causes of substance abuse. Behavioral therapies, such as CBT, help people learn to cope with stressful situations and triggers in healthier ways, reducing their need for antihistamines.
• Support groups: In the process of recovery, support groups provide a nurturing setting where members exchange personal anecdotes, difficulties, and adaptive mechanisms. Peer support lessens the isolation that is frequently linked to addiction by fostering a sense of connection and understanding.
• Counseling: Counseling sessions, whether individual or group, offer opportunity to address the emotional and psychological components of addiction. These treatments are sympathetic and nonjudgmental, encouraging people to investigate the fundamental causes of their addiction and devise long-term recovery solutions.

When is Antihistamine addiction counseling necessary?

Antihistamine addiction counseling becomes necessary when individuals exhibit signs of dependency or misuse, adversely impacting their daily lives and well-being. If an individual struggles to control their antihistamine use, experiences withdrawal symptoms when attempting to reduce or stop, and continues to use the medication despite negative consequences, counseling is essential. 

Additionally, when antihistamine use interferes with responsibilities, relationships, or mental health, seeking professional counseling becomes crucial. Individuals showing signs of preoccupation with obtaining and using antihistamines, neglecting other aspects of life, or facing challenges in managing stress without the medication will benefit from counseling as well. 

Early intervention through counseling is vital to address antihistamine addiction comprehensively and prevent the escalation of substance misuse.