Drug abuse Flashcards
Describe Serotonin syndrome
- mental effects e.g. agitation
- autonomic effects e.g. labile BP
- neuromuscular change e.g. clonus, tremor, hyperreflexia
Medication error
Any preventable event that may cause or lead to inappropriate medication use or patient harm while the medication is in the control of health professional, patient or consumer. Can be due to prescribing, dispensing or administration.
Types of medication error
- Wrong patient
- Wrong drug
- Wrong dose
- Wrong route
- Inappropriate individual circumstances: drug interactions or contraindicated drug
- Inadequate monitoring
Causes of medication error
- Lack of knowledge: About the drug, About the patient
- Calculation errors (q,v,)
- Poor handwriting, inappropriate abbreviations, and poor use of zeros and decimal points
- Poor history taking (allergies, OTC drugs)
- Lack of time
- Carelessness
- Inadequate checking
- Poor communication
How can medication errors be avoided
- checking patient identity and drug
- education and training
- clear prescription writing
- electronic prescribing
- adverse event reporting
- controlling availability of high risk drugs
- adequate resources and staffing
- good drug and allergy history taking
- failsafe devices
- good communication at handover
Effects of anticonvulsants in pregnancy
- Effect of valproate in-utero: risk of developing autism spectrum disorder, ADHD
- Pre-pregnancy counselling and folate supplements can help
- Worse with phenytoin, carbamazepine and valproate. Better with Lamotrigine and Levetiracetam
Toxic epidermal necrosis
- Causes by: Phenytoin, sulphonamides, allopurinol, penicillins, Carbamazepine, NSAID
- Potentially life threatening skin disorder
- Presented with erythema, pruritus, facial swelling, exfoliative dermatitis and exanthematous rash
- Genetic predisposition: more common in thai or Han Chinese origin
- Management: intravenous immunoglobulins, extensive skin exfoliation
Common narrow therapeutic index drugs
- Carbamazepine
- Cyclosporine
- Digoxin
- Levothyroxine
- Lithium carbonate
- Phenytoin
- Tacrolimus
- Theophylline
- Warfarin
Drug misuse statistics
- 10% of the adult population used drugs in the last year
- 28883 drug misuse deaths last year
- 25,000 hospital admissions due to drug misuse last year
Drug misuse epidemiology
Most popular used drugs: Cannabis, cocaine, ectasy, Hallucinogens, Amphetamines
Age group with the most drug misuse: 25-45
Regions with the most drug misuse: North east, correlation with social deprivation
Most common cause of death due to drug misuse: 2/3rds are opioids particularly heroin and morphine
Other physical harms of drug use
- STI’s, pregnancy, physical accidents and trauma
- IV: blood borne viruses (Hepatitis or HIV), Necrotic ulcer. Get infections with chemical and bacteria injury
- Smoking: increased risk of COPD and cancer
- Inhalation (snorting): pneumothorax, destruction of the nasal septum
Tolerance
The diminishing effect of a drug following repeated administration at a given dose. Mediated by pharmacodynamic mechanisms such as changes in receptor density, for example with opioids, or via pharmacokinetic mechanisms such as induction of metabolic enzyme activity, such as with alcohol
Physical dependence
Develops when neurones adapt to repeated drug exposure and only function normally in the presence of the drug. A key feature of physical dependence is that acute withdrawal precipitates unpleasant physiological effects. Gradual withdrawal of drugs is needed.
Psychological dependence
Emotional need for a drug or substance that has no underlying physical need. Caused by a changes in the dopamine pathway in the nucleus accumbens, with overexpression of deltafosB
Testing for drug use
- Immunoassays: used in patients urine test for classic drugs (Cocaine, Amphetamines, Cannabis, Opioids, Benzodiazepines and Phencyclidine). Don’t test for new Psychoactive substances. Common to get false positives and negatives
- Chromatography mass spectrometry: gold standard. Compares the patients blood, urine or saliva with the reference standard. Can take days-weeks to come back
-Often difficult to identify drug causing toxicity, Need to look at clinical features (Toxic syndrome or ‘Toxidrome)
Opioids clinical features and ingestion methods
- Reduced GCS, reduced ventilation, meiosis (pinpoint pupils), rhinorrhoea, watering eye, yawning. Can cause type 2 respiratory failure, respiratory arrest and aspiration pneumonia
- Can be taken orally (for example MST, tramadol or codeine tablets), intravenously (for example heroin), smoked (heroin) or heated to form a pyrolysate that is then inhaled
- Issues with heroine being contaminated with synthetic opioids like fentanyl
Opioids MoA
Agonism at opioid receptors (G-Protein Coupled Receptors), most commonly µ (mu) and K (kappa) receptors. Classically Mu1 receptors cause analgesia while Mu2 cause respiratory depression and kappa receptors cause sedation
How to give naloxone
- The starting dose in adults is 400microgram IV and if the clinical response is inadequate then escalating doses are given at 1 minute intervals aiming for a GCS above 10 and a respiratory rate above 10.
- Ensure period of observation after naloxone administration
Other sedative drugs
benzodiazepines and GHB type drugs don’t cause meiosis however. GHB type drugs have a shorter half life and causes bradycardia
Management of opioid dependence
- Methadone and Buprenorphine are offered first line in detoxification
- Methadone is a full agonist of the mu opioid receptor whilst Buprenorphine is only partial. Relieves withdrawal symptoms and cravings
- Compliance is monitored using urinalysis
- Normally lasts 4 weeks as a inpatient and 12 weeks in the community
