cptp - poisonig mh misuse of drugs
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PCM
1. Pathways of conjugation aresaturated and co-factors aredepleted and as such moreparacetamol is metabolised viaCYP450
2. Glutathione (GSH) becomes
depleted so cannot detoxifyNAPQI3. Toxic effects
150 mg/kg or 12gm – Fatal 75 mg/kg if malnourished
Phase 1 – 0-24 hoursNausea, vomiting, nothing
Phase 2 – 24-72 hoursRUQ pain, elevated liverenzymes, prolonged PT
Phase 3 – 72-96 hoursHepatic necrosis,encephalopathy, coagulopathy,ATN
Phase 4 – 4 days- 2 weeksIf damage is not irreversible,complete resolution of hepaticdysfunction will occur
GI DECONTAMINATION1. Induce Emesis /Gastric Lavage2. Activated Charcoal
SPECIFIC ANTIDOTEN-Acetyl Cysteine (NAC) – 150
mg/kg IV Infusion over 15 Minutesfollowed by the same dose IV overnext 20 hours
Acetylsalicylicacid (Aspirin)
Methylsalicylate (Oil
ofWintergreen)
Inhibition of cyclooxygenaseresults in decreased synthesis ofProstaglandins, Prostacyclin, andThromboxanes
Stimulation of the CTZ in themedulla causes nausea and
vomiting CNS Direct toxicity Activation of the respiratory
center of the medulla results intachypnea, hyperventilation,respiratory alkalosis
Uncoupled oxidativephosphorylation in themitochondria generates heat andmay increase body temperature
Interference with cellular
metabolism leads to metabolicacidosis
Mild Toxicity - 150 mg/kg Moderate Toxicity – 250 mg/kg Severe Toxicity - > 500 mg/kg Fatal - > 700 mg/kg
MILD - MODERATE Fever Tinnitus Vertigo Nausea & Vomiting
Diarhoea Dehydration Hyperventilation
SEVERE Haemorrhages Hallucinations Hyper/Hypoglycaemia Pulmonary edema Convulsions Coma
Death
Symptomatic & Supportive IV fluids
1.26% Sodium Bicarbonate Alkalinization of Urine (If Plasma
Salicylate level - > 500mg/L) Hemodialysis(If Plasma Salicylate
level - > 700mg/L)
Morphine 50 mg of Morphine IM produces
toxicity in Non-tolerant adult Fatal Dose – 250 mg
Cyanosis Pin point pupil Shallow breathing Stupor Flaccidity Hypotension Convulsions
Respiratory Support IV fluids & Vasopressors Gastric Lavage with Potassium
permanganate Specific Antidote – Naloxone 0.4
– 2 mg IV repeat every 2 minutesuntil breathing is adequate
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Coma Death due to Respiratory
paralysis
Iron Most common in infants and
children
60mg/kg iron causes serious toxicity Haemorrhage Hepatic necrosis Brain damage
Induce Emesis / Gastric lavageSpecific TherapyIron chelating agent Desferrioxamine
15 mg/kg/hr IV InfusionMax – 80 mg/kg/day
TCA
Inhibition of Presynapticneurotransmitter reuptake-Noradrenaline & Seratonin Cardiac fast sodium channels Central and peripheral
muscarinic acetylcholinereceptors
Peripheral alpha-1 adrenergicreceptors
Histamine (H1) receptors CNS GABA-A receptors
Three major toxic syndromes of TCAPoisoning1. Anticholinergic effects2. Cardiac toxicity3. CNS toxicity (sedation and
seizures)Death in TCA overdose is usually dueto CNS and Cardiotoxic effects.Anticholinergic Syndrome
Hot as hell Blind as a bat Dry as a bone
Mad as a hatter
Supportive ABC ECG monitoring
GI Decontamination If patients are alert and co-
operative and have ingested > 5mg/kg, charcoal may beadministered orally
If the patient is unconscious andrequires intubation to protectthe airway insert an orogastrictube, aspirate stomach contentsthen give activated charcoal
Seizures Diazepam 5-20 mg IVPhenobarbitone 15-18 mg/kg IVPhenytoin should be avoided (
sodium-channel blocking)Anticholinergic delirium
Mild delirium can often bemanaged with reassurance plusor minus benzodiazepines
Neuroleptics should be avoided(most of which have significantanticholinergic activity)
BDZ MILD: Drowsiness , Ataxia , COMA 1 (Stage 1): Responsive to SUPPORTIVE PROCEDURES &
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Weakness MODERATE TO SEVERE :Vertigo ,
slurred speech, nystagmus,partial ptosis, lethargy ,hypotension, respiratorydepression, coma (stage 1 & 2 ).
painful stimuli but not to verbal ortactile stimuli, no disturbance inrespiration or BP.COMA 2 (Stage 2):Unconscious, notresponsive to painful stimuli, nodisturbance in respiration or BP.
SYMPTOMATIC / SPECIFICTREATMENT:
Airway , breathing & circulation. IV fluid administration. Endotracheal intubation. Assisted ventilation.
DECONTAMINATION: Stomach wash within 6-12 hrs. Activated charcoal. Emesis is contraindicated.
SPECIFIC ANTIDOTE Flumazenil –reversing the coma
induced by benzodiazepines. Mode of action – competitive
antagonism. Complete reversal of
benzodiazepine effect with atotal slow iv dose of 1mg.
Administered in a series ofsmaller doses beginning with 0.2mg & progressively increasingby 0.1- 0.2 mg every minute untila cumulative total dose of 3.5mg is reached.
Organophosphorus
Generally manifests in minutes tohoursEvidence of cholinergic excessSLUDGE = Salivation,
Lacrimation,Urination,Defecation,Gastric Emptying.
BBB = Bradycardia,Bronchorrhea,
Bronchospasm.
Respiratory insufficiency canresult from muscle weakness,
decreased central drive,increased secretions, andbronchospasm and it is theleading cause of death.
Cardiac arrhythmias, includingheart block and QTc prolongatio
Termination of exposure byremoval of contaminatedclothes, washing of skin
Gastric lavage. Maintenance of patent airway
Artificial respiration Intravenous fluids
Specific Antidotes(a) Inj.atropine 2mg iv (every 10 mintill signs of atropinization appears)(b) Inj.pralidoxime 1-2g iv (children20-40 mg/kg)
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MENTALHEALTH
MOA INDICATION ADVERSE EFFECTS
SSRI– FLUOXETINE
SertralineCitalopramMirtazapine
Inhibit serotonin reuptake. Increasedconcentrations of the neurotransmitter in thesynaptic cleft and ultimately, to greaterpostsynaptic neuronal activity.
Depression, OCD, PTSD, Panic disorder,generalised anxiety disorder, premenstrualdystrophic disorder, bulimia nervosa (fluoxetine)
Nausea, sleep disturbance, sexual dysfunction,drowsiness, drug interaction
Mirtazapine – weight gain + sedation
TCA– AMITRIPTYLINE
Inhibits neurotransmitter reuptake.Blocking of receptors
Moderate to severe depression. Panic disorder.Migraine, chronic pain syndrome.
Blurred vision, dry mouth, urinary retention,sinus tachycardia, constipation, and aggravationof narrow-angle glaucoma.
SNRI -VENLAFAXINE
Inhibits NA reuptake and mild inhibitor ofdopamine reuptake at high doses.
DepressionNausea, headache, sexual dysfunction,constipation, sedation, insomnia, dizzy
1st generation -HALOPERIDOL
Competitive inhibitor of D2 dopamine receptors.
4. Schizophrenia5. Severe N&V6. Agitated and disruptive behaviour
Movement disorder. High potential of EPSDid not ameliorate “negative” symptoms
2nd generation – OLANZAPINERisperidoneQuetiapineAripiprazoleClozapine
Dopamine receptor-blocking activity in the brainand periphery.Serotonin receptor-blocking activity in the brain,particularly 5-HT2A receptors
EPS – dystonias, akathisias (x leh duduk diam,nak jalan je), bradykinesia, rigidity, tremor,tardive dyskinesia