Type of Product
Selective central presynaptic alpha-2 adrenergic receptor agonist and imidazoline receptor agonist. In high concentrations non-selective activation of peripheral alpha-1 adrenoceptors is thought to occur.
Used in the management of hypertension, migraine, vascular headache, menopausal symptoms, sedation and for analgesia. Also used in the treatment of children with attention deficit hyperactivity disorder, and Tourette syndrome.
Ingredients
Clonidine hydrochloride
Tablets - 0.025 mg, 0.1 mg
Injection (1 mL amp) - 0.15 mg/mL
Oral - 0.05 mg/5mL solution
Toxicity
Toxicity results primarily from the central sympathetic depressant effects of the drug (Catapres SPC, 2017).
Children are particularly at risk and and 1 or 2 tablets may cause symptoms (Eddy & Howell, 2003).
In a review of 27,825 paediatric clonidine exposures 45% of cases presented with CNS depression, 10% bradycardia, 9% hypotension, 3% had respiratory features and 7 (0.025%) patients suffered a cardiac arrest (Wang et al, 2014).
In a series of 11 toddlers who ingested 0.01-0.57 mg/kg clonidine, all developed an altered level of consciousness; 5 developed miosis, hypotension and hypothermia; 6 developed both apnoea and respiratory depression; and 8 developed bradycardia. Mild features were present in patients who have ingested less than 0.01 mg/kg. Patients who had ingested more than 0.02 mg/kg are at significant risk of respiratory depression (Fiser et al, 1990).
In a retrospective study of 40 adults ingesting clonidine at doses between 400-15,000 micrograms; 68% developed bradycardia which persisted for a median of 20 hours, 55% of patients developed a decreased level of consciousness, 25% became hypotensive, and 5% were comatose (Isbister et al, 2017).
Click
here for further case reports of clonidine exposure.
Clonidine is well absorbed via ingestion and dermally, with peak plasma concentrations and maximal hypotensive effect occurring 1 to 5 hours after an oral therapeutic dose and 1 hour after topical application (Bassani & Banov, 2016). Steady state features usually manifest rapidly within 30 to 90 minutes and rarely develop if symptom-free more than 4 hours after ingestion. The elimination half-life of clonidine ranges between 5 and 24 hours but can be prolonged up to 41 hours in patients with severely impaired renal function (Catapres SPC, 2013).
Gabapentin
Type of Product
An anticonvulsant and analgesic used for neuropathic pain. Also used off-license for migraine prophylaxis.
A potential drug of abuse as notified by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) in 2013.
Ingredients
Gabapentin
Capsules - 100 mg, 300 mg, 400 mg
Tablets - 600 mg, 800 mg
Oral solution (150 mL bottle) - 50 mg/mL
Toxicity
Exact mechanism of action and toxicity unknown. It is a structural analogue of GABA but does not appear to act on GABA receptors (Rose & Kam, 2002).
A 62-year-old woman was found dead with high plasma levels of gabapentin. While the total dose ingested was unknown, a prescription of 150 capsules of 300 mg gabapentin was dispensed one day prior. Post-mortem findings showed a blood concentration 88 micrograms/mL (therapeutic concentration: 2.6 micrograms/mL). Gabapentin was the only drug found in excess (Middleton, 2011). However, a 59-year-old woman is reported to have had symptoms of only mild sedation and nausea after ingesting approximately 90 g (serum concentration 72.8 micrograms/mL) (Schauer & Varney, 2013).
A case series of 20 gabapentin overdoses in adults and children (doses 50 mg to 35 g) reported symptoms of drowsiness, dizziness/ataxia, nausea/vomiting, tachycardia and hypotension (Klein-Schwartz et al, 2003).
Peak plasma concentrations are reached 2-3 hours after an oral dose. Bioavailability of a 300 mg capsule is approximately 60% but decreases with increasing dose. The therapeutic half-life is 5-7 hours (Gabapentin SPC, 2018).
Features
The most significant effect in overdose is CNS depression, which may occasionally be profound. Ataxia, nystagmus, agitation, slurred speech and myoclonus are reported. Very rarely convulsions may occur.
GI upset, hypotension, tachycardia, syncope, ECG abnormalities such as AV block and cardiac failure may also occur.
Rhabdomyolysis and acute kidney injury have been reported.
When co-ingested with alcohol, opiates and other central nervous system depressants, the effects of gabapentinoids are potentially more severe.
Hypersensitivity reactions have been reported shortly after starting pregabalin therapy.
Oxycodone
Type of Product
Semisynthetic opioid analgesic.
Ingredients
Oxycodone
Modified release tablets - 5 mg, 10 mg, 15 mg, 20 mg, 30 mg, 40 mg, 60 mg, 80 mg, 120 mg
Capsules - 5 mg, 10 mg, 20 mg
Tablets - 5 mg, 10 mg, 20 mg
Oral solution - 1 mg/mL, 10 mg/mL
Injection - 10 mg/mL, 50 mg/mL
Orodispersible tablets - 5 mg, 10 mg, 20 mg (available in Ireland)
Toxicity
The most serious toxic features are respiratory depression, hypercapnoea, reduced consciousness/coma and airway obstruction, mediated by mu and kappa opioid receptor agonism. The toxic dose is very variable according to individual tolerance. These effects will be potentiated by simultaneous ingestion of other sedatives including alcohol.
Tablets may be crushed and snorted or injected for recreational use.
A 45-year-old woman who ingested up to 4 g of sustained release oxycodone received a total of 188 mg intravenous naloxone over 11 hours. Following this she required mechanical ventilation for 2 days; the patient recovered (Schneir et al, 2002).
Nasal insufflation of oxycodone can cause nasal abscess and nasopharyngeal necrosis (Pulia & Reiff 2014; Rosenbaum et al, 2012).
A retrospective review of a clinical database reported that oxycodone was associated with bradycardia and QT prolongation in around 20% of 137 overdoses (Berling et al, 2013). However, this may be confounded by the effects of other co-ingested cardiotoxic drugs.
In comparison with morphine, oxycodone has a high absolute bioavailability of 87% after oral administration. Peak plasma concentrations are reached within 1-1.5 hours after ingestion of normal release preparations, and 3 hours after ingestion of sustained release preparations. Oxycodone has an elimination half-life of approximately 3.5 hours in normal release preparations and 4.5 hours in sustained release preparations (Lynlor capsules SPC, 2021; Oxycontin SPC, 2021).
Features
Severe opioid toxicity produces depression of the respiratory and central nervous systems and pin-point pupils. If untreated the depression of the level of consciousness can lead to deep coma, convulsions and respiratory arrest.
- Effects in overdose will be potentiated by co-ingestion of alcohol and other centrally acting drugs.
- Effects will appear very rapidly after exposure to high-potency opioid drugs (e.g. veterinary sedating agents like etorphine).
- Severe and recurrent respiratory depression can occur after ingestion of transdermal patches.
Milder opioid toxicity may produce nausea, vomiting, nightmares, anxiety, agitation, euphoria, dysphoria, depression, paranoia and hallucinations. While pin-point pupils are often present, this is not a reliable clinical sign and their absence does not exclude opioid toxicity. Sedation may be associated with hypotension, bradycardia and hypothermia.
Toxic leukoencephalopathy has been reported following recreational use of heroin, methadone, oxycodone and buprenorphine. Malignant cerebellar oedema and raised intracranial pressure has been reported in one child following unintentional dihydrocodeine ingestion.
For certain opioids (such as morphine, diamorphine, codeine and pethidine), the risk of toxicity is significantly increased if kidney function is impaired due to reduced elimination of the parent opioid or active metabolite.
Opioids, in particular codeine, can cause histamine release, causing urticaria and pruritis. Non-cardiac pulmonary oedema and rhabdomyolysis may occur after intravenous injection of opioid analgesics.
Some opioids may cause cardiotoxicity e.g. methadone, which causes potassium channel blockade and QT prolongation or dextropropoxyphene, which causes sodium channel blockade and QRS prolongation.
Co-administration of opioids with serotonergic agents such as SSRIs, SNRIs, MAOIs etc. may increase the risk of serotonin syndrome. For more information click
here. For the management of serotonin syndrome click
here.
The route of opioid administration may produce important clinical features such as soft-tissue infections and abscesses at the sites of intravenous heroin injection. The presence of infections distant to the injection site should also be specifically determined (for example, endocarditis, lung abscesses). Inadvertent intra-arterial injection can cause severe limb ischaemia.
The possibility of viral hepatitis and HIV infection should be considered in all intravenous drug users and testing should be routinely offered or recommended.
Rarely, sudden sensorineural hearing loss (SSHL) has been reported following opioid overdose. Recovery of hearing has been reported in some cases.
Flubromazepam HIGHLY TOXIC SUBSTANCE
Type of Product
A drug of abuse. A benzodiazepine.
Synonyms
Flubromazepam
Caution: using a slang term/abbreviation to try and identify a drug of abuse is potentially dangerous since there are many regional variations and the terms change over time.
Ingredients
7-bromo-5-(2-fluorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one
Caution: exact ingredients may vary. Different products will have different compositions. The label may not accurately reflect the contents.
Caution: the purity of the ingredients in recreational drugs may vary greatly.
Toxicity
At the time of writing, there was limited information on the toxicity of this drug. It is anticipated that it will be like other benzodiazepines in its toxicity.
Benzodiazepines cause CNS depression through their agonist action at the (GABAA) receptor. Features of severe toxicity include coma, hypotension, bradycardia, respiratory depression, rhabdomyolysis and hypothermia. Effects are likely to be more severe when co-ingested with alcohol and other CNS depressants.
A half-life of 100 hours has been reported for this flubromazepam, however this was in a single individual (following an oral dose of 4 mg; Moosmann et al, 2013).
Flubromazepam was detected in 0.65% of samples from 766 patients presenting to participating Emergency Departments in the UK with severe toxicity related to suspected NPS use since 2015 (IONA study, 2020, unpublished data).
Features
Benzodiazepines commonly cause drowsiness, ataxia, dysarthria and nystagmus. Coma, hypotension, bradycardia and respiratory depression occasionally occur but are seldom serious if these drugs are taken alone. Coma usually lasts only a few hours but may be prolonged in elderly patients.
Benzodiazepine respiratory depressant effects are more serious in patients with chronic obstructive airways disease. Severe effects in overdose also include rhabdomyolysis and hypothermia.
ECG abnormalities include transient first degree and second degree block and QT prolongation. Abnormal LFTs may also occur.
Microembolisation can result from intravenous injection of crushed tablets. Accidental intra-arterial injection of benzodiazepines can cause severe limb ischaemia and gangrene necessitating limb amputation.
Co-ingestion of alcohol and other central nervous system depressants potentiates the effects of benzodiazepines and can increase toxicity.
Flubromazolam
Type of Product
A drug of abuse. A benzodiazepine.
Synonyms
Flubromazolam
Caution: using a slang term/abbreviation to try and identify a drug of abuse is potentially dangerous since there are many regional variations and the terms change over time.
Ingredients
8-bromo-6-(2-fluorophenyl)-1-methyl-4H-[1,2,4]triazolo-[4,3a][1,4]benzodiazepine
Caution: exact ingredients may vary. Different products will have different compositions. The label may not accurately reflect the contents.
Caution: the purity of the ingredients in recreational drugs may vary greatly.
Toxicity
At the time of writing, there was limited information on the toxicity of this drug. It is anticipated that it will be like other benzodiazepines in its toxicity.
Benzodiazepines cause CNS depression through their agonist action at the (GABAA) receptor. Features of severe toxicity include coma, hypotension, bradycardia, respiratory depression, rhabdomyolysis and hypothermia. Effects are likely to be more severe when co-ingested with alcohol and other CNS depressants.
Flubromazolam is reported to be highly potent, causing strong sedation and amnesia following oral doses as low as 0.5 mg (Moosmann et al, 2015).
A 27-year-old male who reportedly ingested 3 mg of flubromazolam developed severe, prolonged depression of the central nervous system with cardio-respiratory failure (Lukasik-Glębocka et al, 2016).
Features
Benzodiazepines commonly cause drowsiness, ataxia, dysarthria and nystagmus. Coma, hypotension, bradycardia and respiratory depression occasionally occur but are seldom serious if these drugs are taken alone. Coma usually lasts only a few hours but may be prolonged in elderly patients.
Benzodiazepine respiratory depressant effects are more serious in patients with chronic obstructive airways disease. Severe effects in overdose also include rhabdomyolysis and hypothermia.
ECG abnormalities include transient first degree and second degree block and QT prolongation. Abnormal LFTs may also occur.
Microembolisation can result from intravenous injection of crushed tablets. Accidental intra-arterial injection of benzodiazepines can cause severe limb ischaemia and gangrene necessitating limb amputation.
Co-ingestion of alcohol and other central nervous system depressants potentiates the effects of benzodiazepines and can increase toxicity.