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    Dihydrocodeine molecular structure

    Dihydrocodeine Stats & Data

    dhc
    NPS DataHub
    MW301.39
    FormulaC18H23NO3
    CAS125-28-0
    IUPAC4,5α-epoxy-3-methoxy-17-methylmorphinan-6α-ol
    SMILESCOc1ccc2CC3N(C)CCC45C3CCC(O)C5Oc1c24
    InChIKeyRBOXVHNMENFORY-DNJOTXNNSA-N
    Chemical Class medicine
    Psychoactive Class Depressant
    Half-Life 3.3–4.5 hours (mean ~4 h)

    Pharmacology

    DrugBank
    Half-life 4h State Solid

    Description

    Dihydrocodeine is an opioid analgesic used as an alternative or adjunct to codeine to treat moderate to severe pain, severe dyspnea, and cough. It is semi-synthetic, and was developed in Germany in 1908 during an international search to find a more effective antitussive agent to help reduce the spread of airborne infectious diseases such as tuburculosis. It was marketed in 1911.

    Mechanism of Action

    Dihydrocodeine is metabolized to dihydromorphine -- a highly active metabolite with a high affinity for mu opioid receptors.

    Pharmacodynamics

    Possible opioid related side effects include, but are not limited to, drowsiness, nausea, headache, dry mouth, constipation, difficulty passing urine, and mild euphoria.

    Metabolism

    Metabolized in the liver by CYP 2D6 into an active metabolite, dihydromorphine, and by CYP 3A4 into secondary primary metabolite, nordihydrocodeine. A third primary metabolite is dihydrocodeine-6-glucuronide. The time for mean peak concentration in acid metabolites is 1.76h and 1.98h for a 30 and 60mg dose, respectively. The concentrations achieved were 563 ug/1 and 1476 ug/1, respectively.

    Absorption

    Bioavailability is low (approximately 20%) if administered orally. This may be due to poor gastrointestinal absorption. It is also likely due to pre-systemic metabolism by the liver and intestinal wall. The AUCs after oral and intravenous administration are similar (3203ug/l/h and 3401ug/l/h, respectively). Time to peak values are 1.6 and 1.8hours for a 30mg and 60mg dose, respectively. The concentrations achieved were 71.8 ug/1 and 146 ug/1, respectively.

    Indication

    Dihydrocodeine is used for the treatment of moderate to severe pain, including post-operative and dental pain . It can also be used to treat chronic pain , breathlessness and coughing. In heroin addicts, dihydrocodeine has been used as a substitute drug, in doses up to 2500mg/day to treat addiction. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2014322/

    Elimination

    Renal elimination and urinary excretion.

    Volume of Distribution

    The disposition of dihydrocodeine is described as a two compartment model.

    Clearance

    Plasma clearance is approximately 300ml/min. The pharmacokinetics of dihydrocodeine and active metabolite dihydromorphine have been reported to be linear. The decline in plasma dihydrocodeine concentrations after intravenous administration has been described as bi-exponential, with a sleep decline in the initial 2h following administration, followed by a mono-exponential decline thereafter. Clearance was not dose dependent.

    Receptor Profile

    Receptor Actions

    Agonists
    μ-opioid receptor agonist (full)

    Receptor Binding

    Mu-type opioid receptor antagonist

    History & Culture

    1908–1911

    Dihydrocodeine is a semi-synthetic opioid that was developed in Germany in 1908 during a period of intensive research into more effective antitussive agents. This effort was motivated by the urgent need to limit the transmission of airborne infectious diseases, particularly tuberculosis, pertussis, and pneumonia, which were major public health concerns during the late 19th and early 20th centuries. The compound entered the market in 1911 and was later granted formal regulatory approval for medical use in 1948.

    In clinical settings, dihydrocodeine has been employed as a substitution therapy for individuals with heroin dependence, with doses reaching up to 2500mg daily. Japan represents a notable exception in global drug policy, where dihydrocodeine remains available without prescription. It appears in over-the-counter cough preparations such as New Bron Solution-ACE, serving as an alternative to dextromethorphan. Japanese manufacturers typically formulate these products with caffeine to counteract sedative effects and reduce the potential for recreational misuse.

    Subjective Effect Notes

    physical: The physical effects of dihydrocodeine can be broken down into several components which progressively intensify proportional to dosage.

    cognitive: The cognitive effects of dihydrocodeine can be broken down into several components which progressively intensify proportional to dosage. The general head space of dihydrocodeine is described by many as one of intense euphoria, relaxation, anxiety suppression and pain relief.

    Effect Profile

    Curated + 15 Reports
    Opioid 6.4

    Strong euphoria with moderate itching/nausea, mild pain relief and sedation

    Euphoria / Warmth×3
    10
    Analgesia×2
    4
    Sedation / Relaxation×1
    4
    Itching / Nausea×1
    7

    Tolerance & Pharmacokinetics

    drugs.wiki
    Half-Life
    3.3–4.5 hours (mean ~4 h)
    Addiction Potential
    Moderate to high; risk increases with frequent dosing, higher total daily doses, and polydrug use.

    Tolerance Decay

    Full tolerance 7d Half tolerance 3d Baseline ~10d

    Tolerance develops rapidly with near‑daily use and decays over days to weeks after cessation. After a break, prior doses can overshoot—restart with markedly lower doses to reduce overdose risk. Cross‑tolerance exists across mu‑agonist opioids but is incomplete.

    Cross-Tolerances

    Other opioids (e.g., codeine, morphine, oxycodone)
    70% ●○○

    Experience Report Analysis

    Erowid
    15 Reports
    2003–2017 Date Range
    7 With Age Data
    6 Effects Detected

    Demographics

    Gender Distribution

    Age Distribution

    Reports Over Time

    Effect Analysis

    Erowid

    Effects aggregated from 15 experience reports (15 Erowid)

    15 Reports
    6 Effects Detected
    5 Positive
    1 Adverse
    0 Neutral

    Effect Sentiment Distribution

    Confidence Distribution

    Positive Effects 5

    Euphoria 60.0% 70%
    Sedation 46.7% 70%
    Anxiety Suppression 40.0% 70%
    Stimulation 33.3% 70%
    Pain Relief 33.3% 70%

    Adverse Effects 1

    Headache 33.3% 70%

    Real-World Dose Distribution

    62K Doses

    From 41 individual dose entries

    Oral (n=40)

    Median: 30.0mg 25th: 8.0mg 75th: 79.5mg 90th: 126.0mg
    mg/kg median: 1.013 mg/kg 75th: 1.641

    Form / Preparation

    Most common forms and preparations reported

    Redose Patterns

    Redosing behavior across 11 reports

    18.2% Redosed
    1.2 Avg Doses

    Opioid Equivalence (MME)

    NIH HEAL 2024 & CDC 2022
    ⚠ Citation & Disclaimer: Conversion factors sourced from the NIH HEAL Initiative MME Calculator (Adams et al., PAIN 2025), the CDC 2022 Clinical Practice Guideline for Prescribing Opioids for Pain, and the MDCalc MME Calculator. These are approximate equianalgesic ratios for educational reference only. Individual responses vary significantly based on genetics, tolerance, cross-tolerance, and route of administration. This is not medical advice. Do not use these conversions to adjust opioid dosing without professional medical guidance.
    40 mg Dihydrocodeine 10 mg Morphine (oral)
    MME factor 0.25×

    Dihydrocodeine 40 mg oral ≈ 10 mg Morphine oral

    Semi-synthetic opioid related to codeine. Evidence level: Moderate (B).

    Legal Status

    Country Status Notes
    Japan Unscheduled (OTC available) Available without prescription in over-the-counter cough preparations such as cough syrups. Represents a notable exception in global drug policy where dihydrocodeine remains accessible for consumer purchase without a medical prescription.

    Harm Reduction

    drugs.wiki

    Low oral bioavailability (~21%) and a delayed peak (~1.6–1.8 h) increase the risk of impatient redosing; wait at least 2 hours to assess effects before taking more. The parent drug and its metabolites (notably dihydromorphine and DHC‑6‑glucuronide) mediate effects; CYP2D6 O‑demethylation is polymorphic and inhibited by some medications, so potency can vary widely between people and with drug–drug interactions. Most non‑medical harms come from polydrug use: combining opioids with benzodiazepines and/or alcohol markedly elevates overdose risk via additive respiratory depression. Many DHC products are combined with acetaminophen; do not exceed 4,000 mg acetaminophen in 24 h from all sources to avoid potentially fatal hepatotoxicity (reduce to ≤3,000 mg/day if risk factors exist). Avoid crushing/chewing controlled‑release tablets; as with other extended‑release opioids, tampering can cause dose dumping and life‑threatening overdose. Carry naloxone if using opioids; it reverses respiratory depression within minutes but may wear off in 20–40 minutes—always call emergency services. Nasal use of tablets exposes sinuses to insoluble binders and offers little benefit; prefer oral use of known single‑ingredient products. Tolerance builds quickly; after even short breaks, tolerance drops and the prior ‘usual’ dose may cause overdose—start low again. Opioids predictably cause constipation; start prevention early (fluids, fiber, movement; consider stimulant or osmotic laxatives if needed). Avoid driving or operating machinery while sedated; opioid effects can outlast the perceived ‘high,’ and some services recommend at least 24 hours before driving after recreational use.

    References

    Data Sources

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