Antihistamine addiction is an increasingly recognized dependency on allergy medications, characterized by physical and psychological symptoms resulting from habitual overuse. Although antihistamines are prescribed for allergy relief, some individuals consume them excessively, seeking their sedative effects. Common antihistamines that are abused are diphenhydramine (found in Benadryl), promethazine, hydroxyzine, and chlorpheniramine.
Among 92,033 overdose deaths in 2019–2020, 13,574 (14.7%) were antihistamine-positive, and 3,345 (3.6%) were antihistamine-involved, with fewer than 0.1% (90) involving only antihistamines. Nearly all of these cases (13,475, 99.6%; 3,339, 99.8%) involved first-generation H1 antihistamines, primarily diphenhydramine (9,645, 71.1%; 2,226, 66.5%) according to the Centers for Disease Control (CDC) publication by Dinwiddie et al. 2022 in “Notes from the Field: Antihistamine Positivity and Involvement in Drug Overdose Deaths — 44 Jurisdictions, United States, 2019–2020.”
The symptoms of antihistamine addiction include cravings for the drug, increased tolerance requiring larger doses, withdrawal symptoms upon cessation, the continued use of antihistamines despite negative consequences, and changes in behavior, such as neglecting responsibilities or engaging in risky activities while under the influence.
Antihistamine addiction side effects are drowsiness, cognitive impairment, and mood disturbances, making withdrawal a challenging experience marked by intense withdrawal symptoms. In England, antihistamines were involved in 42.4% of antihistamine-related suicides, compared to 33.0% of unintentional deaths, according to Roussin et al. 2013 in “Misuse and Dependence on Non-Prescription Codeine Analgesics or Sedative H1 Antihistamines by Adults: A Cross-Sectional Investigation in France.”
The main treatment options for antihistamine addiction are detoxification, behavioral therapies, support groups, and counseling to support recovery. There are cases of antihistamine addiction treatment that involve addressing co-occurring mental health issues. Ongoing support and monitoring are necessary to prevent relapse and ensure sustained recovery.
What Is Antihistamine Addiction?
Antihistamine addiction is a medical condition marked by the excessive and uncontrollable consumption of antihistamine medications. These medications are primarily used to treat allergies and related symptoms by blocking histamines, which are chemicals responsible for allergic reactions.
Over time, certain individuals begin misusing antihistamines for their sedative effects, leading to dependency. Although not as common as other substance addictions, antihistamine addiction affects individuals across all age groups, especially those seeking to self-medicate for anxiety or sleep disturbances.
The study “Misuse and Dependence on Non-Prescription Codeine Analgesics or Sedative H1 Antihistamines by Adults: A Cross-Sectional Investigation in France” explores the misuse, abuse, and dependence of non-prescription psychoactive drugs in self-medication. Of 295 participants, 6.8% misused and 17.8% developed dependence on codeine analgesics, with 19.5% using them daily for over six months, primarily for chronic headaches. High rates of daily doxylamine use were also reported, with 72.2% using it beyond the recommended duration. Findings underscore the need for improved care in managing chronic pain and sleep disorders as observed by Roussin et al, 2013.
What Are the Symptoms of Antihistamine Addiction?
The symptoms of antihistamine addiction are cravings for antihistamines, difficulty stopping use, and physical and psychological issues related to dependency. These symptoms aggravate tolerance, requiring higher doses to achieve the same effects. Individuals experience withdrawal symptoms such as anxiety, irritability, and sleep disturbances when attempting to minimize or stop antihistamine use. First-generation H1-antihistamines, perceived as safe due to their long history of use, are sedating and have been shown to have negative effects on sleep and cognitive performance. These medications reduce rapid eye movement (REM) sleep, impair learning, and decrease work efficiency, as discussed in studies like Church et al. 2010 in “Risk of First-Generation H1-Antihistamines: A GA2LEN Position Paper.”
The common symptoms of antihistamine addiction include:
- Intense cravings for antihistamines: Individuals experience a persistent and overpowering desire to use antihistamines, exhibiting compulsive behavior and an inability to stop.
- Increased tolerance, needing larger doses for effects: As the body adapts to the drug, users require higher doses to achieve the same effects, escalating the risk of overdose.
- Frequent drowsiness or sedation: Regular use of antihistamines induces ongoing drowsiness, impairing daily functioning and alertness.
- Cognitive impairment, including memory loss and confusion: Long-term misuse negatively impacts cognitive functions, precipitating memory issues and difficulty concentrating.
- Mood swings or increased irritability: Antihistamine abuse exacerbates fluctuations in mood, aggravating irritability, or emotional instability.
- Lethargy and decreased motivation: Addiction instigates a lack of energy, motivation, and interest in activities, resulting in social withdrawal.
- Disrupted sleep patterns: While antihistamines initially induce sleep, long-term abuse engenders irregular sleep cycles or insomnia.
What Are the Side Effects of Antihistamine Addiction?
The side effects of antihistamine addiction are cognitive impairment, mood disturbances, and physical health complications. Long-term antihistamine abuse negatively impacts mental health, physical well-being, and social functioning. First-generation antihistamines were linked to a 22% increased risk of seizures, particularly in children aged 6 to 24 months, in a cohort of 3,178 children in Korea as investigated by Kim et al. 2024 in “First-Generation Antihistamines and Seizures in Young Children.”
The common side effects of antihistamine addiction include:
- Drowsiness and sedation: Antihistamines are central nervous system depressants, hence substantial sedation, which harms daily functioning, reaction times, and motor coordination.
- Memory issues: Chronic use of sedative antihistamines, especially first-generation H1 blockers, interferes with neurotransmitters involved in memory, setting in motion confusion and memory impairment.
- Mood changes: Antihistamine misuse elicits mood fluctuations, consisting of irritability and depression, as the drug affects brain chemistry and emotional regulation.
- Decreased cognitive function: Prolonged antihistamine use impairs cognitive functions such as concentration, decision-making, and learning, which have serious implications for daily life and professional tasks.
- Constipation or urinary retention: Antihistamines block acetylcholine, a neurotransmitter that helps regulate smooth muscle movement, bringing about frequent side effects like constipation and urinary retention.
- Blurred vision: As a side effect of anticholinergic action, antihistamines create blurry vision, especially with excessive or prolonged use.
- Dry mouth and eyes: Antihistamines inhibit secretions from glands, leading to dry mouth and dry eyes, which worsen with overuse or misuse of the medication.
What are the Withdrawal Symptoms of Antihistamine Addiction?
The withdrawal symptoms of antihistamine addiction include irritability, anxiety, and insomnia. Withdrawal symptoms are severe, especially for individuals who have been consuming high doses for extended periods. A patient with chronic diphenhydramine (DPH) abuse, involving several hospitalizations for intoxications and overdoses, showed signs of withdrawal. IV administration of 50 mg of DPH resulted in immediate improvement of tremor, rigidity, tachycardia, and eye movements. The patient was started on oral DPH (50 mg, four times daily), with a 25% dose reduction every three days. Clonidine (0.1 mg, three times daily) and a 0.1 mg weekly transdermal patch were added to manage sympathetic symptoms, as reported by Saran et al. 2017 in “Chronic Diphenhydramine Abuse and Withdrawal: A Diagnostic Challenge.”
The common withdrawal symptoms of antihistamine addiction include:
- Anxiety: Anxiety is attributed to increased feelings of nervousness and agitation as the body adjusts to the absence of the sedative effects of antihistamines, encompassing racing thoughts and restlessness.
- Insomnia: Insomnia is difficulty in sleeping or staying asleep, brought about by the cessation of the drug’s calming properties. Sleep disturbances persist for several days or longer.
- Nausea and vomiting: Nausea and vomiting are common withdrawal symptoms as the body expels the drug. This is accompanied by stomach cramps and discomfort.
- Sweating: Excessive perspiration, particularly during the night, as the body experiences a physiological reaction to the loss of antihistamine’s sedative effects.
- Tremors: Uncontrolled shaking, in the hands or extremities, due to the nervous system’s reaction to antihistamine withdrawal.
- Headaches: Severe headaches, sometimes with dizziness or lightheadedness occur as the body adjusts to the drug’s absence.
- Irritability: Heightened mood swings and emotional distress, engendering frustration or anger, as the brain chemistry shifts without the drug’s influence.
How Long Does Antihistamine Withdrawal Last?
Antihistamine withdrawal lasts 2-3 days, post-24 hours of the last dose. The most intense symptoms subside after a week, although mild symptoms like anxiety and mood swings persist for several weeks, depending on the individual’s level of dependency and duration of misuse. Antihistamine addiction weaning is done gradually by minimizing the daily dose by 25-50% every 1 to 4 weeks. For the final stage, a slower reduction of 12.5% is recommended. The treatment is concluded two weeks after the lowest dose is reached to minimize withdrawal effects, according to the NSW Therapeutic Advisory Group Inc. (2018).
What Are the Treatments for Antihistamine Addiction?
The main treatments for antihistamine addiction are detox, inpatient rehab, behavioral therapies, support groups, and counseling. Each approach addresses specific aspects of addiction recovery, providing a structured and supportive environment to overcome dependence. These approaches aid individuals to safely withdraw from antihistamines, tackle underlying psychological issues, and maintain long-term recovery. Common treatments for antihistamine addiction are given as follows:
Detox
Detoxification involves safely removing antihistamines from the body under medical supervision, addressing withdrawal symptoms specific to antihistamine addiction. This process may include medications to manage symptoms like tremors, anxiety, and insomnia. Detox serves as a critical first step, stabilizing individuals physically and psychologically for further treatment.
Inpatient Rehab
Inpatient rehabilitation offers 24-hour care for individuals with severe antihistamine addiction. This treatment includes medical supervision, therapy, and a controlled environment to prevent relapse. Inpatient rehab is especially beneficial for those needing intensive care, helping them avoid access to antihistamines during recovery.
Behavioral Therapies
Behavioral therapies, including Cognitive Behavioral Therapy (CBT), help individuals identify and alter thought patterns and behaviors associated with antihistamine addiction. Therapy sessions focus on building skills to manage cravings, resist triggers, and reduce psychological dependence on antihistamines.
Support Groups
Support groups provide a communal space for individuals recovering from antihistamine addiction to share experiences, offer mutual support, and maintain accountability. These groups foster encouragement and emotional healing, which are key to sustaining long-term recovery.
Counseling
Counseling, offered in individual or group formats, addresses the emotional and psychological roots of antihistamine addiction. Sessions support individuals in exploring the underlying factors contributing to their dependency, managing co-occurring mental health issues, and developing healthier coping strategies for a drug-free future.
Who Is at Risk for Antihistamine Addiction?
The people at risk for antihistamine addiction include individuals with history of substance abuse, trauma, or co-occurring mental health disorders are at higher risk for antihistamine addiction. Young adults and adolescents are particularly vulnerable, as they are more likely to experiment with medications. Additionally, individuals who regularly self-medicate for anxiety or sleep issues without proper medical guidance are also at risk. For pediatric use, the maximum daily dose of hydroxyzine must not exceed 2mg/kg, with a maximum of 50mg per day for children weighing less than 40kg, as indicated by Bryne et al. 2017 in “Are Antihistamines Effective in Children? A Review of the Evidence.” The Partnership Attitude Tracking Study 2003, referred to as the “Teens Study,” highlighted the growing concern over prescription and over-the-counter (OTC) medication abuse among adolescents, a practice known as “pharming.” In 2005, nearly 20% of teens in grades 7 through 12 reported using prescription medications to “get high.”
What Are the Commonly Abused Antihistamines?
Commonly abused antihistamines are over-the-counter medications like diphenhydramine (Benadryl), cetirizine (Zyrtec), and loratadine (Claritin). These antihistamines are readily accessible and have sedative properties that make them appealing for misuse. The sale of antihistamines grew at a compound annual growth rate (CAGR) of 5.9% from 2017 to 2022. The demand for these products is expected to remain strong due to their increased accessibility through retail pharmacies, hospital pharmacies, and online channels. In 2022, the global antihistamine market was valued at approximately US$ 263.9 billion, and it is projected to expand at a CAGR of 8.6%, reaching an estimated valuation of US$ 647.7 billion by 2033 as proposed by the “Antihistamine Market” report by Future Markets Insights.
Can You Overdose on Antihistamines?
Yes, you can overdose on antihistamines and it is life-threatening. Symptoms of an overdose include confusion, seizures, rapid heart rate, and severe drowsiness. In 2019–2020, 13,574 (14.7%) of the 92,033 overdose deaths were antihistamine-positive, while 3,345 (3.6%) were antihistamine-involved, and fewer than 0.1% (90) involved only antihistamines, as reported by the Centers for Disease Control and Prevention (2022) in the study “Notes from the Field: Antihistamine Positivity and Involvement in Drug Overdose Deaths — 44 Jurisdictions, United States, 2019–2020.”
Can Antihistamines Cause Anxiety?
Yes, antihistamines can contribute to anxiety, certainly when used in high doses or frequently. Certain first-generation antihistamines, known for their sedative effects, trigger paradoxical reactions, leading to symptoms of anxiety, especially when taken in large doses or for extended periods. This is exacerbated in those who are already sensitive to such side effects.
In some individuals, taking Benadryl has a stimulant effect known as paradoxical excitation. This occurs because, rather than simply blocking histamine receptors, first-generation antihistamines like Benadryl act as inverse agonists on the H1 receptors. Instead of producing the usual effect of histamine binding, these drugs create the opposite response, setting forth accelerated agitation, restlessness, or even anxiety. This mechanism is explained by the molecular biology of histamine interaction with H1-receptors, as discussed by Church D. & Church M. 2011 in “Pharmacology of Antihistamines” and supported by other research into antihistamine pharmacodynamics.
Does Antihistamine Addiction Affect Your Sleep?
Yes, antihistamine addiction does affect your sleep. While antihistamines like Benadryl are used for their sedative properties to help with sleep, prolonged use or addiction to these medications disrupt sleep patterns. People who misuse antihistamines experience withdrawal symptoms like insomnia when they stop using them, as their body has become dependent on the drug’s sedating effects.
A randomized controlled trial by Staevska et al. 2014 “Night-time Sedating H1 -Antihistamine Increases Daytime Somnolence But Not Treatment Efficacy in Chronic Spontaneous Urticaria: A Randomized Controlled Trial,” tested the effectiveness of levocetirizine 15 mg daily plus hydroxyzine 50 mg at night versus levocetirizine 20 mg daily for chronic spontaneous urticaria (CSU). Both treatments cut symptom severity and sleep disturbances, but only levocetirizine monotherapy reduced daytime somnolence (P = 0.006, a 0.6% probability that the result is due to chance, suggesting a strong effect). The addition of hydroxyzine did not ameliorate treatment efficacy and failed to lessen daytime sleepiness (P = 0.218, a 21.8% chance that the result occurred by chance, which is not statistically relevant), pivoting guidelines favoring nonsedating antihistamines.
