WARNINGDELIRIANTS CAUSE DANGEROUS PSYCHOSIS & ARE EXTREMELY TOXIC
Hallucinations under the influence of deliriants are experienced as genuine reality, blending seamlessly with the external environment. This is in combination with overwhelmingly uncomfortable physical side effects and a complete absence of recreational or therapeutic value.
Dimenhydrinate
Dimenhydrinate is an over-the-counter first-generation antihistamine composed of diphenhydramine and 8-chlorotheophylline in a 1:1 salt form.citation needed Introduced in 1949 by G.D. Searle, it is primarily used to prevent motion sickness and nausea, a therapeutic application discovered accidentally during antihistamine research. At higher doses, dimenhydrinate produces deliriant effects characterized by dysphoric, realistic hallucinations, functioning at roughly half the potency of diphenhydramine alone.
Dosage & Duration
Dosage
Doses are population estimates that vary widely between individuals.
The dose-response relationship for dimenhydrinate is nonlinear. At amounts under 300 mg, effects generally include restlessness, muscle relaxation, and altered bodily sensations. Above 500 mg, a deliriant state may emerge, characterized by vivid visual and auditory hallucinations. Doses between these ranges often produce dysphoria and significant discomfort. Amounts approaching or exceeding 2 grams carry serious risk of fatal overdose, especially in combination with other stimulants or MAOIs.
Duration
Subjective Effects
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At recreational doses, dimenhydrinate produces a deliriant state characterized by confusion, disorientation, and realistic hallucinations that are frequently dysphoric in tone. Unlike classical psychedelics, the experience offers little insight or euphoria; users commonly describe it as uncomfortable, with excitement and restlessness giving way to delirium in which the boundary between hallucination and reality dissolves. The effect profile closely resembles tropane alkaloid (anticholinergic) poisoning, and the body load is considerable throughout.
Physical
The body load is heavy and predominantly anticholinergic: dry mouth and mucous membranes, dry flushed skin, blurred vision, urinary retention, and rapid heart rate. Motor impairment is prominent, with ataxia, tremors, muscle cramps, and a feeling of heaviness in the legs; drowsiness dominates at lower doses while higher doses tend to keep the user awake and restless.
Anticholinergic
A cluster of effects consistent with anticholinergic toxicity accompanies recreational use.
Coordination
Uncomfortable
Cognitive
The headspace is confused, dysphoric, and disorganized, marked by delirium, paranoia, and temporary amnesia attributed to decreased acetylcholine signaling. At higher doses, thought becomes so disordered that users may lose awareness of having taken a drug at all.
Emotional
Suppressions
Cognition is broadly suppressed rather than enhanced, with confusion and memory loss forming the core of the headspace.
Visual
Visual effects consist of distortions and blurring that progress into realistic hallucinations at deliriant doses. Pupil dilation contributes to blurred vision and light sensitivity.
Auditory
Auditory distortions are common, along with an unusual sensitivity to sudden sounds; hallucinated sounds and voices can accompany the deliriant state.
See also: Subjective Effects of Deliriants
Pharmacology
Pharmacodynamics
Dimenhydrinate is a theoclate salt that dissociates into diphenhydramine (53-55.5% by weight) and 8-chlorotheophylline (44-47% by weight).citation needed Diphenhydramine is the primary pharmacologically active constituent, functioning as a histamine H1 receptor antagonist with additional muscarinic acetylcholine receptor antagonist activity. Its antiemetic properties are attributed primarily to H1 antagonism within the vestibular system, though antimuscarinic effects may also contribute to this action. The 8-chlorotheophylline component acts as an adenosine receptor antagonist, providing mild stimulant properties that partially counteract diphenhydramine-induced sedation.
Pharmacokinetics
Following oral administration, the diphenhydramine component reaches peak plasma concentrations in approximately 2 to 3 hours, with an elimination half-life of 5 to 8 hours in healthy adults.citation needed Diphenhydramine undergoes hepatic metabolism via N-demethylation by CYP2D6, CYP1A2, CYP2C9, and CYP2C19, producing successive demethylated metabolites, as well as N-glucuronidation by UGT enzymes. Dimenhydrinate is 70-85% protein bound with a volume of distribution of 3-4 L/kg. Elimination is predominantly renal, with approximately 64% of diphenhydramine excreted in urine as metabolites and 1-3% excreted unchanged.
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
Tolerance
Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.
Anticholinergic deliriants (diphenhydramine, other first-generation antihistamines), H1 antihistamines
Harm Potential
Addiction & Dependence
Psychological
LowEthanolamine-class antihistamines are thought to have relatively low abuse liability due to their dysphoric and unpleasant side-effect profile.citation needed While recreational use as a deliriant does occur, the experience is typically not reinforcing.
Toxicity
Considerable overdosage can cause serious cardiovascular complications including myocardial infarction and ventricular arrhythmias;citation needed tachycardia occurs during intoxication as an expected anticholinergic effect.
Long-term repeated use of anticholinergic drugs, including first-generation antihistamines, has been linked to a greater risk of cognitive decline and dementia in older adults; this association is not regarded as clinically meaningful for younger people.
Anticholinergic toxicity manifests at the neuromuscular junction and sympathetic post-ganglionic junctions, causing ataxia, urinary retention, pupil dilation, irregular urination, and dry red skin;citation needed these effects are dose-dependent and occur primarily at recreational or overdose doses.
Psychosis Risk
As a deliriant, dimenhydrinate produces hallucinations, delirium, and psychosis at recreational doses.citation needed Effects include realistic visual and auditory hallucinations, paranoia, confusion, and unusual sensitivity to sudden sounds. These psychotomimetic effects are an expected consequence of high-dose anticholinergic intoxication rather than an adverse reaction.
Seizure Risk
Convulsions are reported in overdose situations in both children and adults.citation needed Tremors may occur at recreational doses. Extrapyramidal side effects have also been noted.
History & Culture
Discovery and Development
Dimenhydrinate, originally designated Compound 1694, was developed through serendipitous observation rather than targeted research. In 1947, allergists Dr. Leslie Gay and Dr. Paul Carliner at Johns Hopkins Hospital were testing the compound as a potential treatment for hay fever and…
Legality
By Country
References
Source Pages
Citations
- Gareth J. Sanger, & Paul L. R. Andrews. (2018). A History of Drug Discovery for Treatment of Nausea and Vomiting and the Implications for Future Research. Frontiers in Pharmacology, 9. https://doi.org/10.3389/fphar.2018.009131
- GRAVOL TABLETS — Drug Product Database, Health Canada. Health Canada (n.d.). https://health-products.canada.ca/api/drug/drugproduct/?din=000138031
- DIMENHYDRINATE INJECTION USP — Drug Product Database, Health Canada (DIN 00392537). Health Canada (n.d.). https://health-products.canada.ca/api/drug/drugproduct/?din=003925371
- Drugs@FDA: ANDA080715 — Dimenhydrinate (ALRA), openFDA. U.S. Food and Drug Administration / openFDA (n.d.). https://api.fda.gov/drug/drugsfda.json?search=application_number:ANDA080715&limit=11
- DRAMAMINE ORIGINAL FORMULA — dimenhydrinate tablet, DailyMed (setid f9302a5a-295a-4501-9332-e3f5eb387362). U.S. National Library of Medicine / DailyMed (n.d.). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f9302a5a-295a-4501-9332-e3f5eb3873621
- Dimenhydrinate injection, solution. U.S. National Library of Medicine (n.d.). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=bc71539e-1a33-4709-8a24-c2894e8dbc1c1
Further Reading
Article Status
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Lyrea · Changed a word in Dosage & Duration › Routes 1 › Dose ranges › Threshold
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