generation run 2026-05-09
61 min completedmodel pipeline-v5plan not recordedrun/070d4106…Selection
Verification
- record
- seen / partial
- working
The model's own caveats
- sparse_evidence
- structural_inference
Reproduce
- inputs
- 40 source keys (listed under Sources)
- plan
- not recorded — template version, prompt hash and git SHA are written from 2026-09 onward
- model
- pipeline-v5
- streams
- none — agent transcripts are persisted from 2026-09 onward
21 searches — query, source, results, what was kept and why
| # | source | query | seen | kept | rationale |
|---|---|---|---|---|---|
| 1 | PubMed | dihydrocodeine opioid interaction alcohol respiratory depression | 1 | 1 | Safety interactions information |
| 2 | PubChem | dihydrocodeine | 1 | 1 | Primary chemical identity data |
| 3 | PubMed | dihydrocodeine pharmacology opioid receptor binding | 8 | 8 | All highly relevant to DHC pharmacology, binding affinities, and safety |
| 4 | PubMed | dihydrocodeine analgesic efficacy clinical trial pain | 10 | 3 | Clinical efficacy and comparative data for DHC |
| 5 | ClinicalTrials.gov | dihydrocodeine | 10 | 1 | Only specifically DHC-focused trial found |
| 6 | PubMed | dihydrocodeine CYP2D6 metabolism dihydromorphine | 9 | 5 | Core metabolism pathway papers |
| 7 | PubMed | dihydrocodeine overdose toxicity death fatality | 4 | 3 | Critical safety and mortality data |
| 8 | PubMed | dihydrocodeine pharmacokinetics bioavailability metabolism | 7 | 5 | Primary PK data for DHC |
| 9 | OpenAlex | dihydrocodeine opioid analgesic | 10 | 3 | High-quality reviews with direct relevance to DHC pharmacology and clinical use |
| 10 | PubMed | dihydrocodeine lofexidine opioid detoxification | 3 | 2 | DHC use in addiction treatment and opioid detoxification |
| 11 | Crossref/verify_doi | DOI 10.1016/j.pain.2013.12.016 | 1 | 1 | DOI verification for key clinical trial |
| 12 | WebSearch/DrugBank | dihydrocodeine SMILES PubChem DrugBank | 10 | 2 | Chemical identity data |
| 13 | WebSearch | dihydrocodeine scheduling Australia Canada Germany | 10 | 2 | Scheduling data for additional jurisdictions |
| 14 | WebSearch | dihydrocodeine history synthesis first described 1908 | 10 | 2 | Historical origin data |
| 15 | WebSearch | dihydrocodeine legal status scheduling DEA UK controlled substance | 10 | 2 | Authoritative legal status data for major jurisdictions |
| 16 | PubMed | dihydrocodeine opioid interaction alcohol respiratory depression | 3 | 1 | Drug interaction mechanism for opioid+alcohol |
| 17 | PubMed | dihydrocodeine opioid heroin addiction substitution treatment | 2 | 1 | Historical DHC substitution therapy data in Germany |
| 18 | WebFetch · absence | FPM dose equivalents opioids | 0 | 0 | Access denied; FPM dose conversion data not retrieved |
| 19 | Research synthesis | Summary of all DHC research findings | 42 | 1 | Full research synthesis completed |
| 20 | WebSearch | dihydrocodeine equianalgesic morphine dose conversion WHO | 10 | 0 | Gap identified and flagged |
| 21 | PubMed | dihydrocodeine dyspnea breathlessness palliative care | 1 | 1 | Evidence for opioid use in palliative dyspnea (DHC application context) |
98 claims by section — every cited sentence, checked against its source
safety23 · 21 ok
Rock and colleagues analyzed DHC-related deaths in England from 2001 to 2020 and identified increasing trends in DHC-implicated fatalities over this periodsupported
DHC considered 'weak' opioid but evidence of increasing misuse in overdose deaths. Analyzes trends in DHC-related deaths in England by source, dose, and demographics. j.drugalcdep.2022.109376
Klinder and colleagues reported femoral blood DHM concentrations of 0.16–0.21 mg/L in three fatalitiessupported
DHC and metabolites in femoral blood from three fatal cases. DHM concentrations 0.16-0.21 mg/L. pmid:10335876
Aderjan reported serum DHM concentrations of 0.16–0.22 mg/L in three additional fatal casessupported
DHC metabolism studied in three patients who died from overdoses. DHM concentrations 0.16-0.22 mg/L serum. pmid:9780136
Because DHM has mu-receptor affinity comparable to morphine, DHM accumulation contributes significantly to lethality even when parent DHC concentrations appear relatively low.supported
DHM has similar binding affinity to morphine at mu-receptors. Metabolite determination important in interpreting cause of death. pmid:10335876
Hawton and colleagues studied relative toxicity of analgesics in intentional self-poisoning by comparing case fatality ratios across overdose episodes.supported
Analgesics used most frequently in fatal and non-fatal medicinal self-poisonings. Knowledge about relative toxicity important for clinicians and regulatory agencies. j.jad.2019.01.002
Shimizu and colleagues reported respiratory depression in a 1-month-old neonate receiving prescribed DHC 2 mg/day, with disproportionately high DHC concentrations (400 nmol/L) measured 21 hours post-dose, attributed to developmental immaturity of glucuronidation pathways.partially supported
Neonate case: respiratory depression after prescribed DHC 2mg/d. Neonatal clearance impaired by underdeveloped glucuronidation. ftd.0000000000000482
Renal accumulation of glucuronide metabolites is documented, with potential for prolonged narcosis and respiratory depression in patients with renal insufficiency.supported
Case reports of prolonged narcosis with codeine and dihydrocodeine in renal insufficiency. Care needed when prescribing. pmid:8968655
Renal accumulation of glucuronide metabolites is documented, with potential for prolonged narcosis and respiratory depression in patients with renal insufficiency.supported
DHC and codeine accumulation may explain adverse reactions in impaired renal function. pmid:3322755
Freye and colleagues demonstrated dose-independent prolongation of oro-cecal transit time at 60 mg and 120 mg controlled-release DHC.supported
CR DHC 60 and 120 mg caused significant prolongation of oro-cecal transit (constipation). No significant dose difference between 60 and 120 mg for these effects. pmid:11215327
Prescrire International argued that so-called weak opioids, including DHC, carry no less risk than low-dose morphine at equivalent analgesic doses — a position supported by comparable rates of respiratory depression, constipation, and dependence.supported
Review: weak opioids (codeine, DHC, tramadol) have same adverse effects as morphine. No evidence that weak opioids are less addictive than low-dose morphine. pmid:27042732
Pharmacovigilance data from EudraVigilance and FAERS databases confirm abuse, misuse, and dependence signals for DHCsupported
Pharmacovigilance signals for abuse, misuse, dependence for codeine, DHC, fentanyl, oxycodone, pentazocine, tramadol in EV and FAERS 2003-2018. ph15060675
Historical data from Germany document patterns of compulsive DHC use among polydrug-dependent individuals since the 1960s.supported
Since 1960s in West Germany, increasing abuse of codeine and dihydrocodeine-containing drugs as substitutes and alternatives. Case reports on addiction development. pmid:1869234
The Leeds detoxification study used DHC combined with lofexidine as the standard protocol, implying that DHC itself produces opioid-type physical dependence amenable to structured taperingpartially supported
In Leeds UK, dihydrocodeine is the detoxification agent of choice for heroin users. RCT comparing DHC vs buprenorphine for heroin detoxification in primary care. pmid:15117415
McWhirter and Morris described successful management of kratom withdrawal using DHC, further confirming its capacity to produce and manage opioid-type dependence.supported
DHC and lofexidine effective for kratom withdrawal. Demonstrates DHC cross-reactivity with mu-opioid receptor-dependent withdrawal syndromes. 000320288
Claim in safety — inconclusiveinconclusiveworking →
Claim in safety — inconclusiveinconclusiveworking →
Severe hepatic impairment: Reduced first-pass metabolism increases oral bioavailability, and impaired oxidative clearance prolongs drug exposure.supported
Hepatic cirrhosis reduces oxidation of opioids; DHC has increased oral bioavailability due to reduced first-pass metabolism in liver disease. pmid:10451781
Severe hepatic impairment: Reduced first-pass metabolism increases oral bioavailability, and impaired oxidative clearance prolongs drug exposure.supported
Hepatic cirrhosis increases oral bioavailability of DHC due to reduced first-pass metabolism. Dose reduction required. pmid:12799931
Severe renal impairment: Glucuronide metabolite accumulation produces prolonged narcosis and respiratory depression.supported
Case reports of prolonged narcosis with codeine and dihydrocodeine in renal insufficiency. pmid:8968655
Severe renal impairment: Glucuronide metabolite accumulation produces prolonged narcosis and respiratory depression.supported
DHC and codeine accumulation may explain adverse reactions in impaired renal function. pmid:3322755
Severe renal impairment: Glucuronide metabolite accumulation produces prolonged narcosis and respiratory depression.supported
Opioid use in renal impairment can cause increased adverse effects. 0269216311406313
Neonates and infants: Immature glucuronidation capacity produces disproportionate drug accumulation.supported
Neonatal clearance impaired by underdeveloped glucuronidation. ftd.0000000000000482
Paralytic ileus or obstructive bowel disease: DHC reduces gastrointestinal motility via peripheral mu-receptor activation.supported
CR DHC 60 and 120 mg caused significant prolongation of oro-cecal transit (constipation). pmid:11215327
pharmacology21 · 17 ok
Dihydrocodeine is a full agonist at mu (µ)-, delta (δ)-, and kappa (κ)-opioid receptors, with highest affinity at the mu receptorsupported
Ki of DHC at mu-opioid receptor = 0.3 micromol/L; dihydromorphine and DHM-6-O-glucuronide had at least 70x greater affinity. pmid:12420793
Dihydrocodeine is a full agonist at mu (µ)-, delta (δ)-, and kappa (κ)-opioid receptors, with highest affinity at the mu receptorsupported
Binding studied on guinea-pig brain homogenates. Substitution of the free phenolic group (as in DHC vs morphine) causes decreased receptor binding. pmid:7885194
Mignat and colleagues demonstrated in guinea pig brain homogenates that this methyl ether substitution reduces mu affinity without altering the mu/delta selectivity ratiopartially supported
Binding studied on guinea-pig brain homogenates. Substitution of the free phenolic group (as in DHC vs morphine) causes decreased receptor binding. pmid:7885194
Thompson and colleagues measured agonist-stimulated [³⁵S]GTPγS binding in cell membrane preparations and found that 7,8-saturated codeine congeners, including DHC, were more efficacious than codeine at stimulating mu-receptor-mediated G-protein activationsupported
7,8-saturated codeine congeners (DHC, hydrocodone, oxycodone) are more efficacious than codeine at mu-receptors. pmid:14600248
Claim in pharmacology — inconclusiveinconclusiveworking →
Claim in pharmacology — inconclusiveinconclusiveworking →
O-demethylation to dihydromorphine (DHM): Catalyzed by CYP2D6. DHM has approximately 70-fold greater mu-receptor affinity than the parent compound and pharmacological properties similar to morphine.partially supported
First detailed investigation of DHC metabolism pathways in humans. Tested hypothesis that O-demethylation to DHM is catalyzed by polymorphic CYP2D6. pmid:7586928
O-demethylation to dihydromorphine (DHM): Catalyzed by CYP2D6. DHM has approximately 70-fold greater mu-receptor affinity than the parent compound and pharmacological properties similar to morphine.partially supported
Using human liver microsomes from CYP2D6 poor and extensive metabolizer genotypes, investigated individual CYP enzymes in oxidative metabolism of DHC. pmid:9431830
O-demethylation to dihydromorphine (DHM): Catalyzed by CYP2D6. DHM has approximately 70-fold greater mu-receptor affinity than the parent compound and pharmacological properties similar to morphine.supported
Ki of DHC at mu-opioid receptor = 0.3 micromol/L; dihydromorphine and DHM-6-O-glucuronide had at least 70x greater affinity. About 7% of Caucasian population are CYP2D6 poor metabolizers. pmid:12420793
Claim in pharmacology — inconclusiveinconclusiveworking →
Claim in pharmacology — inconclusiveinconclusiveworking →
Glucuronidation: Produces DHC-6-O-glucuronide, DHM-3-O-glucuronide, and DHM-6-O-glucuronide. The latter has high mu affinity comparable to morphine-6-glucuronide.supported
DHM binding affinity to mu-receptor higher than morphine; DHM6G as high as M6G. pmid:9780136
Steady-state pharmacokinetics were characterized by Ammon and colleagues in 12 healthy CYP2D6 extensive metabolizers (EMs) receiving single (60 mg) and multiple (60→90→120 mg twice daily) oral dosessupported
12 CYP2D6 EMs. Single oral 60 mg and steady-state doses. Dose linearity of AUC, Cmax, Cssmin for DHC and DHM. pmid:10510141
Cowan and colleagues confirmed that a controlled-release formulation (DHC bitartrate 90 mg) and immediate-release solution (3 × 30 mg) achieved comparable total bioavailability, with mean urinary recovery of approximately 30 mg in each armsupported
Bioavailability of controlled-release DHC bitartrate (90mg) vs solution (3x30mg). Mean urinary recovery ~30mg each; comparable bioavailability. pmid:3171947
Approximately 7% of Caucasians are CYP2D6 poor metabolizers (PMs), producing reduced or absent DHMsupported
About 7% of Caucasian population are CYP2D6 poor metabolizers. pmid:12420793
Unlike codeine — for which CYP2D6 PM status results in near-complete therapeutic failure — DHC retains meaningful mu-receptor activity as a parent compound, making therapeutic failure less complete in PMssupported
DHC analgesia appears CYP2D6-independent due to parent compound effects, multiple metabolic pathways, limited role of DHM. 17512433.2016.1092871
DHC is not separately addressed in Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines for CYP2D6-guided opioid prescribing, further distinguishing it from codeine in terms of CYP2D6 dependence.supported
CPIC guideline for CYP2D6 genotype and opioid prescribing. Covers codeine, tramadol, hydrocodone, oxycodone, methadone. cpt.2149
Hepatic cirrhosis reduces oxidative metabolism, resulting in increased oral bioavailability and decreased clearance; dose reduction is requiredsupported
Hepatic cirrhosis reduces oxidation of opioids; DHC has increased oral bioavailability due to reduced first-pass metabolism in liver disease. pmid:10451781
Renal insufficiency leads to accumulation of glucuronide metabolites, with case reports documenting prolonged narcosis and respiratory depressionsupported
Case reports of prolonged narcosis with codeine and dihydrocodeine in renal insufficiency. Care needed when prescribing. pmid:8968655
Renal insufficiency leads to accumulation of glucuronide metabolites, with case reports documenting prolonged narcosis and respiratory depressionsupported
DHC and codeine accumulation may explain adverse reactions in impaired renal function. pmid:3322755
Dose reduction is required in significant renal impairment.supported
Opioid use in renal impairment can cause increased adverse effects. Systematic review of opioid guidelines. 0269216311406313
pharmacokinetic-detail12 · 12 ok
Cowan and colleagues showed that a single 90 mg controlled-release dose and three 30 mg immediate-release doses produced equivalent urinary recovery (~30 mg), with no accumulation over four days of repeated dosing and no clinically significant food effectpartially supported
Bioavailability of controlled-release DHC bitartrate (90mg) vs solution (3x30mg). Mean urinary recovery ~30mg each; comparable bioavailability. Controlled-release formulation produces effective steady-state concentrations. pmid:3171947
Ammon and colleagues demonstrated dose-linear pharmacokinetics for both DHC and DHM across single (60 mg) and multiple (60→90→120 mg twice daily) oral doses in 12 CYP2D6 extensive metabolizerssupported
12 CYP2D6 EMs. Single oral 60 mg and steady-state doses. Dose linearity of AUC, Cmax, Cssmin for DHC and DHM. pmid:10510141
Case reports document clinically significant toxicity requiring dose reduction or avoidance in moderate to severe renal failure.supported
Opioid use in renal impairment can cause increased adverse effects. Systematic review of opioid guidelines. 0269216311406313
Shimizu and colleagues reported DHC overdose in a 1-month-old neonate receiving prescribed DHC 2 mg/day, with DHC concentrations of 400 nmol/L and DHM concentrations of 1.9 nmol/L measured 21 hours after the last dosepartially supported
Neonate case: respiratory depression after prescribed DHC 2mg/d. Neonatal clearance impaired by underdeveloped glucuronidation. ftd.0000000000000482
The low oral bioavailability (~21%) reflects extensive first-pass hepatic metabolismsupported
Mean oral bioavailability 21% (range 12-34%). Substantial first-pass metabolism. pmid:6628531
A directly compressible poly(ethylene oxide) matrix sustained-release formulation has also been developed and characterized in vivo.supported
PEO matrix sustained-release formulation for DHC. In vivo bioavailability study confirmed similar PK to DHC Continus commercial product. pmid:14677766
Kirkwood and colleagues subsequently characterized the full suite of CYP enzymes involved using human liver microsomes and selective chemical inhibitors.supported
Using human liver microsomes from CYP2D6 poor and extensive metabolizer genotypes, investigated individual CYP enzymes in oxidative metabolism of DHC. pmid:9431830
The last of these has mu-receptor affinity comparable to morphine-6-glucuronide and may contribute to prolonged opioid effects, particularly during renal impairment.supported
DHM binding affinity to mu-receptor higher than morphine; DHM6G as high as M6G. pmid:9780136
However, because DHC itself is a more efficacious mu-receptor G-protein activator than codeine, therapeutic failure in CYP2D6 PMs is less complete for DHC than for codeinesupported
7,8-saturated codeine congeners (DHC, hydrocodone, oxycodone) are more efficacious than codeine at mu-receptors. DHC does not require O-demethylation for activity, unlike codeine. pmid:14600248
However, because DHC itself is a more efficacious mu-receptor G-protein activator than codeine, therapeutic failure in CYP2D6 PMs is less complete for DHC than for codeinesupported
DHC analgesia appears CYP2D6-independent due to parent compound effects, multiple metabolic pathways, limited role of DHM. 17512433.2016.1092871
Hepatic cirrhosis reduces oxidative metabolism of DHC, resulting in increased oral bioavailability (due to reduced first-pass extraction) and decreased overall clearancesupported
Hepatic cirrhosis reduces oxidation of opioids; DHC has increased oral bioavailability due to reduced first-pass metabolism in liver disease. pmid:10451781
In patients with renal insufficiency, metabolite accumulation — particularly DHM-6-O-glucuronide — leads to prolonged narcosis and respiratory depressionsupported
Case reports of prolonged narcosis with codeine and dihydrocodeine in renal insufficiency. pmid:8968655
summary9 · 9 ok
With oral bioavailability of approximately 21% and an elimination half-life of 3.3–4.5 hours, DHC occupies a position among the so-called "weak" opioids — roughly equipotent to codeine and approximately twice as potent as tramadol by the oral routepartially supported
Half-lives 3.3-4.5h. Mean oral bioavailability 21% (range 12-34%). Substantial first-pass metabolism. pmid:6628531
With oral bioavailability of approximately 21% and an elimination half-life of 3.3–4.5 hours, DHC occupies a position among the so-called "weak" opioids — roughly equipotent to codeine and approximately twice as potent as tramadol by the oral routesupported
Analgesic effect similar to codeine, ~2x tramadol potency orally. 17512433.2016.1092871
Developed in Germany in 1908 and first marketed in 1911, DHC is among the oldest semi-synthetic opioids in continuous clinical usepartially supported
DHC is a semi-synthetic opioid analgesic developed in the early 1900s. pmid:11034754
Its primary therapeutic applications are analgesia (WHO analgesic ladder step 2) and cough suppression, with additional use in opioid substitution treatment — notably in the United Kingdom, where it served as a detoxification agent of choice for heroin-dependent patients in community treatment settingssupported
In Leeds UK, dihydrocodeine is the detoxification agent of choice for heroin users. pmid:15117415
A completed Phase 4 RCT comparing short- and long-acting formulations in chronic non-malignant pain found no superiority for controlled-release preparations.supported
Long-acting DHC (Continus) not superior to short-acting for pain stability, sleep, QoL, depression. j.pain.2013.12.016
The parent compound binds mu receptors with a Ki of approximately 0.3 µmol/L in guinea pig cortex; its principal active metabolite dihydromorphine (DHM), formed via CYP2D6 O-demethylation, achieves approximately 70-fold greater mu affinitysupported
Ki of DHC at mu-opioid receptor = 0.3 micromol/L; dihydromorphine and DHM-6-O-glucuronide had at least 70x greater affinity. pmid:12420793
Unlike codeine, DHC itself demonstrates greater efficacy than codeine at stimulating mu-receptor G-protein activation, providing a mechanistic basis for retained analgesic activity even in CYP2D6 poor metabolizers.supported
7,8-saturated codeine congeners (DHC, hydrocodone, oxycodone) are more efficacious than codeine at mu-receptors. DHC does not require O-demethylation for activity, unlike codeine. pmid:14600248
DHC-related mortality data from England show increasing fatality trends over two decades, and the designation as a "weak" opioid obscures a risk profile comparable to low-dose morphine at equianalgesic dosessupported
DHC considered 'weak' opioid but evidence of increasing misuse in overdose deaths. Analyzes trends in DHC-related deaths in England by source, dose, and demographics. j.drugalcdep.2022.109376
DHC-related mortality data from England show increasing fatality trends over two decades, and the designation as a "weak" opioid obscures a risk profile comparable to low-dose morphine at equianalgesic dosessupported
Review: weak opioids (codeine, DHC, tramadol) have same adverse effects as morphine. No evidence that weak opioids are less addictive than low-dose morphine. pmid:27042732
comparative-pharmacology8 · 7 ok
Reduced CYP2D6 dependence: While both compounds undergo CYP2D6-mediated O-demethylation to high-affinity metabolites (DHM from DHC, morphine from codeine), therapeutic failure in CYP2D6 poor metabolizers is less complete with DHC than with codeine. DHC is not included in CPIC pharmacogenomic dosing guidelines, whereas codeine is.supported
DHC analgesia appears CYP2D6-independent due to parent compound effects, multiple metabolic pathways, limited role of DHM. 17512433.2016.1092871
Reduced CYP2D6 dependence: While both compounds undergo CYP2D6-mediated O-demethylation to high-affinity metabolites (DHM from DHC, morphine from codeine), therapeutic failure in CYP2D6 poor metabolizers is less complete with DHC than with codeine. DHC is not included in CPIC pharmacogenomic dosing guidelines, whereas codeine is.supported
CPIC guideline for CYP2D6 genotype and opioid prescribing. Covers codeine, tramadol, hydrocodone, oxycodone, methadone. cpt.2149
Claim in comparative-pharmacology — inconclusiveinconclusiveworking →
This editorial position challenges the clinical heuristic that step-2 opioids are inherently safer than step-3 agents, and is supported by DHC mortality data from England showing increasing fatality trends over two decades.supported
DHC considered 'weak' opioid but evidence of increasing misuse in overdose deaths. Analyzes trends in DHC-related deaths in England by source, dose, and demographics. j.drugalcdep.2022.109376
Hawton and colleagues compared case fatality ratios across analgesics used in intentional self-poisoningsupported
Analgesics used most frequently in fatal and non-fatal medicinal self-poisonings. Knowledge about relative toxicity important for clinicians and regulatory agencies. j.jad.2019.01.002
Its analgesic potency is approximately equivalent to codeine and roughly twice that of tramadol by the oral routesupported
Analgesic effect similar to codeine, ~2x tramadol potency orally. 17512433.2016.1092871
Higher intrinsic efficacy: DHC demonstrates greater mu-receptor G-protein activation than codeine in [³⁵S]GTPγS binding assays. This means DHC retains meaningful direct opioid activity independent of metabolic conversion.supported
7,8-saturated codeine congeners (DHC, hydrocodone, oxycodone) are more efficacious than codeine at mu-receptors. DHC does not require O-demethylation for activity, unlike codeine. pmid:14600248
Prescrire International argued that so-called weak opioids — including DHC — carry no less risk than low-dose morphine at equivalent analgesic dosessupported
Review: weak opioids (codeine, DHC, tramadol) have same adverse effects as morphine. No evidence that weak opioids are less addictive than low-dose morphine. pmid:27042732
clinical-evidence7 · 6 ok
Claim in clinical-evidence — not_supportednot supportedworking →
A separate case report describes successful management of kratom withdrawal using DHC, supporting its utility as a short-acting opioid for structured tapering.supported
DHC and lofexidine effective for kratom withdrawal. Demonstrates DHC cross-reactivity with mu-opioid receptor-dependent withdrawal syndromes. 000320288
A Cochrane systematic review of single-dose DHC for acute postoperative pain confirmed analgesic efficacy, though the overall evidence base was limited in size and heterogeneous in methodologysupported
DHC is a semi-synthetic opioid analgesic developed in the early 1900s. Used for postoperative pain and as antitussive. Cochrane systematic review of efficacy. pmid:11034754
Pedersen and colleagues conducted an 8-week double-blind, double-dummy RCT (n=60) comparing controlled-release DHC (DHC Continus) with short-acting DHC tablets in patients with chronic non-malignant painsupported
8-week RCT, 60 patients. Long-acting DHC (Continus) not superior to short-acting for pain stability, sleep, QoL, depression. j.pain.2013.12.016
Leppert compared the impact of tramadol and DHC on quality of life in cancer pain patients, contributing to the evidence base for step-2 opioid selectionsupported
Tramadol and DHC are WHO step 2 analgesics. Study assessed impact on QoL and performance status of cancer pain patients. j.1742-1241.2010.02422.x
A Cochrane systematic review confirmed the efficacy of opioids for this indication, and a subsequent systematic review of dyspnea management in cancer patients provided additional supportive evidencesupported
Systematic review of 18 RCTs of opioids for dyspnea. Statistically significant positive effect of opioids on breathlessness. pmid:12403875
The Leeds Evaluation of Efficacy of Detoxification Study (LEEDS) was a randomized controlled trial comparing DHC with buprenorphine for heroin and methadone detoxification in primary care settings in the United Kingdomsupported
In Leeds UK, dihydrocodeine is the detoxification agent of choice for heroin users. RCT comparing DHC vs buprenorphine for heroin detoxification in primary care. pmid:15117415
neuroscience7 · 7 ok
Fatal DHC overdose cases demonstrate this mechanism: post-mortem DHM concentrations of 0.16–0.22 mg/L in blood indicate that metabolite-driven respiratory depression contributes to lethality even when parent compound concentrations appear moderate.supported
DHC and metabolites in femoral blood from three fatal cases. DHM concentrations 0.16-0.21 mg/L. Metabolite determination important in interpreting cause of death. pmid:10335876
Fatal DHC overdose cases demonstrate this mechanism: post-mortem DHM concentrations of 0.16–0.22 mg/L in blood indicate that metabolite-driven respiratory depression contributes to lethality even when parent compound concentrations appear moderate.supported
DHC metabolism studied in three patients who died from overdoses. All metabolites determined. DHM concentrations 0.16-0.22 mg/L serum. pmid:9780136
The approximately 70-fold greater mu affinity of DHM suggests that the reinforcement signal in CYP2D6 extensive metabolizers is predominantly DHM-driven, while in poor metabolizers, DHC's direct (though lower-affinity) mu agonism sustains a reduced but measurable reward signal.supported
Ki of DHC at mu-opioid receptor = 0.3 micromol/L; dihydromorphine and DHM-6-O-glucuronide had at least 70x greater affinity. About 7% of Caucasian population are CYP2D6 poor metabolizers. pmid:12420793
DHC's clinical analgesic efficacy, confirmed across multiple RCTs, is consistent with engagement of this pathway.supported
8-week RCT, 60 patients. Long-acting DHC (Continus) not superior to short-acting for pain stability, sleep, QoL, depression. j.pain.2013.12.016
DHC's clinical analgesic efficacy, confirmed across multiple RCTs, is consistent with engagement of this pathway.supported
DHC is a semi-synthetic opioid analgesic. Used for postoperative pain and as antitussive. Cochrane systematic review of efficacy. pmid:11034754
DHC-specific studies of these molecular mechanisms have not been published, but the compound's full agonist activity at mu receptors predicts engagement of the same tolerance pathways characterized for morphine and other full mu agonistssupported
7,8-saturated codeine congeners (DHC, hydrocodone, oxycodone) are more efficacious than codeine at mu-receptors. DHC does not require O-demethylation for activity, unlike codeine. pmid:14600248
Does DHC's intrinsic G-protein efficacy advantage over codeine translate to differential neural circuit activation? The GTPγS data demonstrate a biochemical difference, but whether this produces distinguishable patterns of brain activation or subjective experience remains untested.supported
7,8-saturated codeine congeners (DHC, hydrocodone, oxycodone) are more efficacious than codeine at mu-receptors; only DHC was more efficacious at delta-receptors. pmid:14600248
history5 · 5 ok
Pharmacoepidemiology data from England spanning 2001–2020 reveal increasing trends in DHC-implicated overdose fatalities, challenging the perception of DHC as a low-risk opioidsupported
DHC considered 'weak' opioid but evidence of increasing misuse in overdose deaths. Analyzes trends in DHC-related deaths in England by source, dose, and demographics. j.drugalcdep.2022.109376
Pharmacovigilance analyses of EudraVigilance and FAERS databases have confirmed abuse, misuse, and dependence signals for DHC at rates warranting continued regulatory attentionsupported
Pharmacovigilance signals for abuse, misuse, dependence for codeine, DHC, fentanyl, oxycodone, pentazocine, tramadol in EV and FAERS 2003-2018. Increase in ADR reports over time. ph15060675
Dihydrocodeine was developed in Germany in 1908 through catalytic hydrogenation of the naturally occurring opium alkaloid codeine, reducing the C7–C8 double bond to a single bondpartially supported
DHC is a semi-synthetic opioid analgesic developed in the early 1900s. pmid:11034754
In the United Kingdom, it acquired particular significance in addiction medicine: in cities such as Leeds, DHC was the detoxification agent of choice for heroin users presenting to community treatment services for much of the late 20th and early 21st centuriessupported
In Leeds UK, dihydrocodeine is the detoxification agent of choice for heroin users. RCT comparing DHC vs buprenorphine for heroin detoxification in primary care. pmid:15117415
Substitution treatment programs using codeine and DHC preparations were studied through the 1990s, with physician and patient outcome assessments documenting both therapeutic benefit and abuse liability.partially supported
Retrospective and prospective study on codeine-based substitution in heroin abusers (n=416). Patients and clinicians reported improvement in health and fewer heroin-related problems. pmid:7480367
receptor-pharmacology4 · 2 ok
Schmidt and colleagues characterized the binding affinities of DHC and its principal metabolites at mu, delta, and kappa opioid receptors using guinea pig cerebral cortex preparations:supported
Dihydrocodeine is metabolized to dihydromorphine, dihydrocodeine-6-O-, dihydromorphine-3-O- and dihydromorphine-6-O-glucuronide, and nordihydrocodeine. Ki of DHC at mu-opioid receptor = 0.3 micromol/L. pmid:12420793
Claim in receptor-pharmacology — inconclusiveinconclusiveworking →
Claim in receptor-pharmacology — inconclusiveinconclusiveworking →
Mignat and colleagues compared binding profiles of morphine, codeine, dihydrocodeine, and their respective glucuronides across opioid receptor subtypessupported
Binding studied on guinea-pig brain homogenates. Substitution of the free phenolic group (as in DHC vs morphine) causes decreased receptor binding. Glucuronidation at 6-position does not affect mu affinity but alters selectivity. pmid:7885194
chemistry2 · 1 ok
Claim in chemistry — inconclusiveinconclusiveworking →
The 3-methoxy substitution renders DHC a prodrug-like compound: CYP2D6-mediated O-demethylation yields dihydromorphine (DHM), which possesses substantially greater opioid receptor affinity.supported
Dihydrocodeine is metabolized to dihydromorphine. Ki of DHC at mu-opioid receptor = 0.3 micromol/L; dihydromorphine and DHM-6-O-glucuronide had at least 70x greater affinity. pmid:12420793