L1: General Toxicology Flashcards
Def of Toxicology
Science dealing with
- Properties
- Actions
- Toxicity
- Autopsy findings (in case of death, in relation to poisonous substances).
- Fatal dose
- Detection
- Estimation
- Treatment
What is a Toxicant?
Specific chemical poisonous.
Categorization of toxic effects
- Toxic effects are categorized according to site of poison effect.
- In some cases, effect may occur at only one site, This site is referred to as specific target organ.
- In other cases, toxic effects may occur at multiple sites.
Types of systemic toxicity
- Acute toxicity
- Subacute toxicity
- Chronic toxicity
Onset of Acute Toxicity
- occurs almost immediately (hours/days) after an exposure.
Causes of Acute Toxicity
usually a single dose or a series of doses received within one day.
Onset of Subacute Toxixity
results from repeated exposure for several weeks or months.
Causes of Subacute Toxixity
This is a common human exposure pattern for some pharmaceuticals and environmental agents
Onset of Chronic Toxicity
- It represents cumulative damage to specific organ systems
- takes many months or years to become a recognizable clinical disease.
Causes of Chronic Toxicity
- Damage due to subclinical individual exposures may go unnoticed but with repeated subclinical exposures, cumulative damage slowly builds up until it exceeds threshold for chronic toxicity.
Manners of posining
Suicidal (Deliberate): Overdose as self-harm.
Accidental: Most episodes of pediatric poisoning, dosage error or iatrogenic.
Homicidal
what are poisons classified according to?
- According to their mode of action
- According to the organs affected: (Target Organ Toxicity).
- According to the chemical nature
Classification of poisons, according to their mode of action
- Poisons with local action
- Poisons with remote action
- Poisons with both local and remote actions
what are posions with local action? and are examples for them?
- They act locally producing immediate destruction of tissues with which they come in contact
e.g., corrosives (except organic acids)
Def of poisons with Remote action
They act only after absorption without any local effects
Examples of poisons with Remote action
plant poisons which act mainly on CNS.
Def of poisons with Local & Remote action
which have a local irritant action on tissues, they come in contact for some time and a remote action (on parenchymatous organs) after absorption.
Examples of poisons with Local & Remote action
irritant metallic poisons
Classification of poison according to organ affected
- Neurotoxic (Brain)
- Hepatotoxic (liver)
- Nephrotoxic (Kidney)
- Cardiotoxic (Heart)
- Immunotoxic
- Respiratory System
- Reproductive System
Examples of Neurotoxic (brain) toxins
- Alcohol
- Lead
Examples of Hepatotoxic (Liver) toxins
- Ethanol
- Acetaminophen
- Phosphorus
- Carbon Tetrachloride.
Examples of Nephrotoxic (Kidney) toxins
Heavy metals e.g., mercury.
Examples of Cardiotoxic (Heart) toxins
Digitalis.
Examples of Immunotoxic toxins
Isocyanates.
Examples of Respiratory System toxins
- Tobacco smoke
- Asbestos
- Ozone.
Examples of Reproductive system toxins
Di-bromochloropropane.
classification of toxins, according to the chemical nature
- Acids
- Alkalis
Examples of acids
- Sulphuric acid
- Nitric acid
- Hydrochloric acid.
Examples of alkalis
Caustic soda
Caustic potash
Ammonium hydroxide
What are factors affecting the severity of toxicity?
- Factors related to the person
- Factors related to the poison
Factors related to the person affecting severity of toxicity
- Age of the person
- Genetic factors
- Personal hypersensitivity
- Tolerance
- Idiosyncrasy
- State of health
- Condition of the stomach
How does age affect the severity of toxicity?
- Children and old people are generally more susceptible to toxic agents
Why are children and people more susceptible to toxic Asians?
Due to decrease of detoxification power.
What can children tolerate, and what can’t they?
Children can tolerate action of atropine, but not morphine.
Person suffering from G6PD deficiency are susceptible at therapeutic doses to hemolytic effect of some drugs like ……..
vitamin K and sulphonamides.
Genetic factors affecting severity of toxicity
Persons suffering from glucose-6-phosphate dehydrogenase deficiency are susceptible at therapeutic doses to hemolytic effect of some drugs
How does personal hypersensitivity affect severity of toxicity?
Very small harmless doses can produce severe symptoms in sensitive patients
Drugs, which are most commonly associated with personal hypersensitivity
Therapeutic dose of penicillin or iodine may produce anaphylaxis in hypersensitive patients.
Describe tolerance
where addicts can stand big dose without ill-effect, So, they have to increase the dose to get same effect.
What causes tolerance?
- Repeated intake of substances of abuse leads to development of tolerance
- So, they have to increase the dose to get same effect.
What is idiosyncrasy?
- Abnormal response to some drugs
Drugs associated with idiosyncrasy
Morphine may produce convulsions instead of depression of CNS.
How does state of health affect severity of success?
Patients suffering from liver or kidney diseases may show signs of increased toxicity of poisons.
Aspects of condition of the stomach
- Type of food
- Gastric secretion
How does type of food affect severity of toxicity?
- Fatty foods delay absorption of arsenic
- while they increase absorption of some poisons as DDT and phosphorus.
How do gastric secretions affect severity of toxicity?
- Poisoning with potassium cyanide may not be fatal
- In case of achlorhydria: as HCL in stomach is important to form severely toxic hydrocyanic acid.
How does state of the poison affect severity of Toxicity?
Poisons in gaseous form are more rapidly absorbed
Factors related to the poison, affecting severity of toxicity
- State of the poison
- Routes of poison administration
- Dose of the poison
- Cumulation
What form of poisons is most Rapidly absorbed?
- Gaseous form are more rapidly absorbed
- Followed by:
Liquid
Fine powder
Big lumps.
Route of administration causes the quickest toxicity?
General scheme for approach of a poisoned patient
what questions should history taking in poisoning include?
- Type of toxins (What)
- Time of toxic exposure (acute versus chronic). (When)
- Amount of toxin taken (How much)
- Route of toxin administration (i.e. ingestion, intravenous, inhalation) (How.).
- Manner of the toxic ingestion or exposure. (Why)
How does Dose of the poison affect severity of Toxicity?
The bigger the dose, the more toxic effect
History taking in poisoning
- History of sudden appearance of toxic manifestations in a healthy person or a group of persons after taking certain food or drink (as food poisoning, methanol and carbon monoxide toxicity).
- History of intake a poison, financial problems, psychiatric troubles, provious altempts at suicide or threatening by somebody.
- History of presence of bottle.of tablets or insecticide near the victim.
- History of patients rescued from fire (CO, cyanido).
Diagnosis of poisoning
- History & Circumstantial evidence
- Clinical Examination: (General & Local)
- Investigations
Psychiatric information in poisoning history Taking
- History of psychiatric illness or previous suicide attempts.
cumulation of poison & its relation to severity of toxicity, then give examples for some drugs that may be accummilated in this way
- After repeated small doses of certain drugs which are not readily metabolized,
- The effect of a single large dose is reached leading to poisoning e.g., digitalis.
What information should history in poisoning include?
- Psychiatric Information
- Drug(s) Information
- Unavailable Information
Drug information in poisoning history Taking
- Information about all drugs taken, including prescription, over the counter medications, vitamins, and herbal preparations.
Examples of Toxidromes
- Sympathomimetic
- Anticholinergic
- Hallucinogenic
- Opiod
- Sedative - Hypnotic
- Cholinergic
What to do if there is unavailable information in poisoning history Taking?
- If history is unavailable from patient, information should be taken from family and friends.
- Paramedics or emergency medical technicians are also good sources of information, because they may be able to furnish details, such as presence of empty pill bottles.
clinical examination in cases of poisoning
Examples of drugs causing Sympathomimetic Toxidrome
Cocaine.
Amphetamine.
Pseudo-ephedrine.
Vital signs in Sympathomimetic Toxidrome
Hyperthermia.
Tachycardia.
Hypertension.
Tachypnea.
Pupils in Sympathomimetic Toxidrome
Mydriasis.
Examples of drugs causing Anticholinergic Toxidrome
Atropine.
Tricyclis-antidepressant.
Antibistamine,
Vital Signs in Anticholinergic Toxidrome
Hyperthermia.
Tachycardia.
Hypertension.
Pupils in Anticholinergic Toxidrome
Mydriasis.
Other findings in Anticholinergic Toxidrome
Hot, dry, red.
Blind.
Seizures.
other findings in Sympathomimetic toxidrome
Piloerection.
Hyperreflexia.
Diaphoresis.
Tremors.
Examples of Drugs causing Hallucinogenic Toxidrome
49-Tetra-Hydrocannabinol.
Phencyclidine.
Lysergic acid diethylamide
Vital Signs in Hallucinogenic Toxidrome
Tachycardia.
Hypertension.
Tachypnea.
Pupils in Hallucinogenic Toxidrome
Mydriasis.
Nystagmus
Other findings in Hallucinogenic Toxidrome
Hallucinations.
Agitation.
Disorientation.
Examples of drugs causing Opiod Toxidrome
Opiates.
Heroin.
Pupils in Opiod Toxidrome
Hypothermia
Bradycardia.
Hypotension.
Hypopnea
Vital Signs in Opiod Toxidrome
Miosis.
Other Findings in Opiod Toxidrome
CNS depression.
Coma.
Antidote
Examples of drugs causing Sedative-Hypnotic Toxidrome
Benzodiazepines.
Barbiturates.
Alcohol, Anticonvulsant.
Vital Signs in Sedative-Hypnotic Toxidrome
Hypothermia
Bradycardia.
Hypotension.
Hypopnea.
Pupils in Sedative-Hypnotic Toxidrome
Miosis (usually)
Examples of Drugs Causing Cholinergic Toxidrome
Organophosphates.
Carbamates.
Mushrooms.
Other Findings in Sedative-Hypnotic Toxidrome
Hyporeflexia.
Confusion.
Stupor.
Coma.
Antidote
Vital signs in Cholinergic Toxidrome
Hypothermia
Bradycardia.
Tachypnea.
Pupils in Cholinergic Toxidrome
Miosis.
Other Findings in Cholinergic Toxidrome
Lacrimation.
Salivation.
Incontinence.
Bronchospasm.
Seizures
DUMBLES
Causes of Coma
- Toxic causes
- Traumatic causes
- Pathologic causes
- Environmental causes
- Hysterical
toxic causes of Coma
Generalized CNS depression:
- (e.g., ethanol, opiates, and sedative-hypnotics).
Post-ictal phenomenon
- after a drug-induced seizure: (e.g. anticholinergics).
Hypoglycemia
- (e.g., insulin, oral hypoglycomic drugs).
Cellular hypoxia:
- (e.g., CO, cyanido).
Pathologic causes of Coma
- Liver and renal failure.
- Infections as encephalitis or meningitis.
Traumatic causes of Coma
Head injuries.
environmental causes of Coma
Hypothermia
Hyperthermia.
hysterical causes of Coma
No organic cause, normal vital signs, and negative investigations
General lines of treatment of Coma
- Care of Airway & Breathing
- Coma cocktail
- Control convulsions
- Correct electrolyte, or acid-base disturbance
- CT Scan
When is Dextrose given in cases of Coma?
- It is given to all patients with depressed consciousness & hypoglycemia.
Dose of dextrose in cases of Coma
- Child: 25 % (2 ml/kg) IV.
- Adolescent/adult: 50 % (1 ml/kg) IV.
When is naloxone given in cases of Coma
It is given to all patients with depressed respiration.
Dose of Naloxone in cases of Coma
- Child: 0.1 mg/kg IV.
- Adolescent/Adult: 0.4 mg IV & 0.1 mg IV “If
suspected Opioid Abuse”. - If no response give up to 2 mg IV.
- If no response, repeat the dose every 2 min. till a total dose of 10 mg.
when is Thiamine given in cases of Coma?
- It is given to malnourished and chronic alcoholic patients.
Dose are thiamine in cases of Coma
100 mg IV or IM (is not given routinely lo children).
Causes of Convulsions
- Toxic causes
- Metabolic Causes
- Traumatic causes
- Pathologic causes
Toxic causes of Convulsions
- Poisons acting on cerebrum
- Poisons acting on brain stem
- Poisons acting on spinal cord
- Poisons causing cerebral anoxia
Poisons acting on cerebrum
- Causing muscular hyperactivity
e.g., amphetamine, cocaine, caffeine and atropine.
Poisons acting on spinal cord
Causing tonic convulsions i.e. sustained hypertonia of the muscles
- e.g., strychnine.
Poisons acting on brainstem
Causing clonic convulsions** i.o., contraction & relaxation of muscles**
- o.g., picrotoxin and lead.
Poisons causing cerebral anoxia
cyanide
Metabolic causes of convulsions
Hypoglycemia, hyponatremia, hypocalcemia, or hypoxia.
Traumatic causes of convulsions
- Head trauma with intracranial injury.
- Idiopathic epilepsy.
- Exertional or environmental hyperthermia
Pathological causes of convulsions
- CNS infection (meningitis or encephalitis)
- Febrile seizures in children.
General lines of treatment of convulsions
- Maintain an open airway and assist ventilation.
- Use one or more of the following anticonvulsants
- Specific measures
- Consider specific antidotes.
Drugs used in cases of convulsions
- Diazepam: 1st Line of therapy:
- Phenobarbitone 2nd Line of therapy:
- Phenytoin: It is not indicated in management of toxic seizures.
Specific measures in cases of convulsions
- Glucose for hypoglycemia.
- Cool Immediately for hyperthermia.
- Fluids for dehydration.
Types of Non-Toxic Indigestion
Def of Non-Toxic Indigestion
- producing little to no toxicity when ingested in small amounts.
- They are not true poisoning and can be managed by reassurance.
Criteria to diagnose non-toxic exposure
To diagnose a non-toxic exposure; all of the criteria should be present:
- Absolute identification of the product.
- Absolute assurance that only 1 product was ingested.
- Absence “NO” signal word (Danger, Poison, Warning, Caution) on the container
- A good approximation of the amount ingested.
- Assurance that the victim is free of symptoms.
- Ability to call back at intervals to determine that no symptoms have developed.
What causes a patient to be asymptomatic after exposure to toxin?
The patient with exposure to toxin may remain asymptomatic due to:
Non-toxic substance: The substance may be nontoxic.
Insufficient amount: An insufficient amount has been ingested
Insufficient absorption: -An sufficient amount has not been absorbed
Investigations in toxocology
General Investigation “Routine Investigations”:
- ECG
- Lab
- Rad
Specific Investigation “Toxicological Investigations” “Toxicology Screen”
General lab investigations in toxicology
- Blood Glucose Level.
- Arterial blood gases
- High anion gap metabolic acidosis (MUD PILES)
- Liver function tests: Clotting profile for paracetamol & anticoagulants toxicities.
- Renal functions tests: Urine analysis for rhabdomyolysis
- Complete Blood Picture.
High anion gap metabolic acidosis
MUD PILES
- Methanol
- Uremia
- Diabetic ketoacidosis
- Propylene glycol
- Iron
- Lactic Acidosis
- Ethanol
- Salicylates
Radiological Examination in toxicology
- Chest X ray
- Abdominal X ray
When is chest x-ray done in toxicology?
If pulmonary edema /aspiration is suspected.
What are drugs that causes pneumonitis or pulmonary edema?
MOPS
- Meprobamate & Methadone
- Opioids
- Phenobarbital, Propoxyphene, Paraquat & Phosgene
- Salicylates
When is abdominal x-ray done in toxicology?
(BETA CHIP).
- Barium
- Enteric coated tablets
- Iricyclic antidepressants
- Antihistamines
- Chloral hydrate, Cocaine
- Calcium
- Heavy metals
- lodides
- Phenothiazines, Potassium
Samples for toxicology screen
Samples are taken from:
- Blood & Urine “Most Indicated”
- Vomitus, Gastric Lavage & Stool “May Indicated”
Value of toxicology screen
The most important evidence of poisoning is by chemical analysis.
Categories of toxicology screen
- Blood levels
- Urine screen
- Specific tests
Blood levels of 3A & 3I toxicology screen
- Alcohols “Ethanol & Mothanol”
- Inotropic “Digoxin & Theophylline”
- Iron
- Analgesic “Paracetamol & Salicylates”
- Anti-Epileptics “Carbamazepine, Phenobarbital”
- Immunosuppressant “Methotrexate”
urine screen
In cases of suspected substance of abuse: ABC
- Amphetamine
- Benzodiazepines & Barbiturates
- Cannabis & Cocaine
- Opioids, Tramadol, Pregabalin, & Synthetic Cannabinoids.
Specific tests toxicology screen
Carboxyhemoglobin levels “if carbon monoxide poisoning is suspected”
General lines of treatment of poison patient
How to prevent further exposure to the poison?
Emergency & supportive treatment
What is the greatest contributor to death from drug overdose and poisoning?
Respiratory failure
How to maintain Airway opening & clearance?
- Airway opening
- Airway clearance
- Maintain airway opened
What maneuver is used for airway opening?
Triple airway maneuver: (Head tilt, jaw thrust, mouth opening)
Airway opening if there is any suspicion of neck injury
Place the patient in left lateral position with head downwards which allows tongue to fall forwards and vomitus or secretions to drain out of the mouth.
Airway clearance
- Finger sweep technique to remove any F.B. or denture
- Suctioning of the mouth and oropharynx to remove secretions.
How to maintain opened airway?
Either by oro or nasopharyngeal airway
What are toxic causes of respiratory failure?
Central Causes:
- opiates, barbiturates, alcohols.
Peripheral Causes
- Airway obstruction
- Neuromuscular block
- Paralysis of respiratory muscles: BOSP
Peripheral causes of toxic respiratory failure
- Airway obstruction
- Neuromuscular block
- Paralysis of respiratory muscles: BOSP
Central causes of toxic respiratory failure
opiates, barbiturates, alcohols.
Peripheral
Toxic causes of airway obstruction
What toxins cause Laryngeal spasm?
cyanide poisoning
What toxins cause oedema of the airway?
irritant fumes or gas such as chlorine inhalation.
What toxins cause bronchospasm?
organophosphates compounds.
What toxins cause excessive secretions?
organophosphate or carbamate toxicity.
What toxins cause Pneumonia?
- From aspiration of Gastric Contents, or hydrocarbons such as Kerosene.
What toxins cause Pulmonary edema?
Organophosphates.
What are toxins that caused neuromuscular block?
Neostigmine and physostigmine.
Methods of breathing support
- 02 mask (Face mask) or bag valve mask (Ambu bag) or Endotracheal intubation (ETT)
- Pulse oximeter to assess 02 saturation:
What are toxins that caused paralysis of respiratory muscles?
BOSP
- Botulinum toxins
- Organophosphates
- Snake bites
- Post convulsive muscle exhaustion.
What are advantages of endotracheal intubation?
- It protects airway and prevents aspiration and obstruction.
- It allows for mechanically assisted ventilation.
- Some emergency drugs can be given through it e.g., naloxone, atropine and opinophrine.
Basics of circularatory support
What to do if there is no pulse?
Perform cardiopulmonary resuscitation
When to begin continuous ECG monitoring?
This is essential for comatose patients and cardiotoxicity.
When is a Foley’s catheter introduced?
- It is placed in bladder if patient is seriously ill (shocked, convulsing or comatose).
- Obtain urine for routine and toxicologic testing and measure hourly urine output.
Disability assessment
- Once ABC is addressed, neurological status should be assessed, mainly level of consciousness, Pupil, Random blood sugar (RBS).
What is Stupor?
It is a grade of unconsciousness in which patient can be aroused (awakened) only by painful stimuli.
What is Coma?
It is a state of prolonged unconsciousness in which patient cannot be aroused by painful stimuli.
Levels of consciousness AVPU Scale
Reed’s classification of level of consciousness
Types of decontamination
- Skin decontamination
- Eye decontamination
- Lungs decontamination
- GIT Decontamination
indications of skin decontamination
Corrosives:
- To prevent skin injury.
Toxins:
That are readily absorbed through the skin:
- To prevent systemic absorption.
As: Organophosphates Insecticides, Paraquat, Phenol & Oxalic Acid.
Steps of skin decontamination
Indications of eye decontamination
Corrosive and Hydrocarbon solvents:
- That can rapidly damage the cornea.
Toxins:
- That are readily skin absorption, can also be absorbed through conjunctiva.
Steps of eye decontamination
Indications of lung decontamination
Irritating gases and fumes:
- As chlorine gas.
Toxins:
- That are absorbed through respiratory tract (Inhalation): As CO, Cyanide, Hydrogen Sulphide & Organophosphates Insecticides.
Steps of lung decontamination
Method of GIT decontamination
- Emesis.
- Cathartics.
- Gastric Lavage.
- Whole Bowel Irrigation.
- Activated Charcoal (Local Antidote).
Emesis as a method of decontamination
currently abandoned.
Def of Cathartics
Substances that enhance passage of materials through the GIT, thus decrease time of contact belween poison and absorptive surface of stomach and intestine.
Types of Cathartics
- Osmotic Cathartics
- Irritant cathartics
examples of Osmotic cathartics
Magnesium Sulfate & Sorbitol.
MOI of Osmotic cathartics
- These are substances that increase osmotic pressure in the intestinal lumen
- Thus causing fluid to be drawn into lumen causing evacuation.
Dose of Osmotic cathartics
1-2 g/kg “Sorbitol”.
Examples of Irritant cathartics
Castor oil
MOI of Irritant cathartics
They act by stimulation of motility
Dose of Irritant cathartics
60-100ml
cautions during using of Irritant cathartics
- In fat soluble toxic substances because they increase their absorption.
- As yellow phosphorus, CCI4 and chlorinated insecticides.
Contraindications of cathartics
- GIT hemorrhage.
- Recent bowel surgery.
- Intestinal obstruction and ileus.
- Renal failure for risk of magnesium load.
Complications of cathartics
- Dehydration particularly in children and elderly
- Electrolyte imbalance.
Indications of Gastric Lavage
- A significant amount of Ingested Toxic Substance within. 1.hour.
- It is usually used for extremoly toxic substances.
- When patient is unable to protect their own airway, intubate
before proceeding.
Procedure of Gastric Lavage
- Place large boro orogastric or nasogastric tubo.
- Confirm placement.
- Warm normal saline is instilled in aliquots until stomach contents are clear.
Technique of Whole Bowel Irrigation
Using a gastric tube, give a surgical bowel-cleansing solution containing a non absorbable polyethylene glycol until rectal effluent is clear.
Contraindications of Gastric Lavage
In cases of:
- Corrosives
- Sharp objects
- Large pills.
Indications of Whole Bowel Irrigation
- Ingestion of large dose of iron or lithium or “Other drugs poorly adsorbed to activated charcoal”.
- Ingestion of Large amount of sustained release or enteric coated tablets.
- Ingestion of foreign bodies or drug filled packets or condoms.
Contraindications of Whole Bowel Irrigation
- lleus or intestinal obstruction.
- Comatose or convulsing patient unless airway is protected by endotracheal tube.
AE of Whole Bowel Irrigation
Nausea, regurgitation and pulmonary aspiration.
MOI of Activated Charcoal
- Almost irreversibly adsorbs drugs and chemicals, preventing absorption
Indications of Activated Charcoal
- Consider for all significant toxic ingestions except poorly binds substances “PGAIS”
Dose of Activated Charcoal
- Give 50 g (adults) or 1 g/kg (children) as a singlo oral doso placed in a cup for self-administration.
- Prepared with a ratio 1:4 charcoal to water
“Goal is to have a charcoal to toxin ratio > 10:1”. - Mixing with ice cream improves palatability for children.
- In intubated patient, AC may be given via oro- or nasogastric tube.
Contraindications of Activated Charcoal
Principle of Enhanced Elimination
- It is used in drug intoxication when renal route is a main route to its total clearance.
- Forced diuresis may increase glomerular filtration rato and ion trapping by urinary pH manipulation may enhance elimination of polar drugs.
- It is used in case of healthy kidney,
Types of Enhanced Elimination
- Urinary Manipulation
- Hemodialysis
- Hemoperfusion
- Hemofiltration
- Peritoneal Dialysis
- Repeated Dose Activated Charcoal (Gut Dialysis)
Types of Urinary Manipulation
- Urinary alkalization
- Urinary acidification
Uses of Urinary alkalization
Uses of Urinary acidification
What characters should a toxin have to undergo Hemodialysis?
Indications of Hemodialysis
Why are Drug size, water solubility and protein binding not important limiting factors in cases of hemoperfusion procedure?
Because drug or toxin is in direct contact with adsorbent material
Advantages of Hemoperfusion
For most drugs, hemoperfusion can achieve greater clearance rates than hemodialysis.
Disadvantages of Hemoperfusion
Systemic anticoagulation is required, often in higher doses than for hemodialysis and thrombocytopenia is a common complication.
Indications of Hemoperfusion
Principle of Hemofiltration
It can remove compounds with large molecular weight through porous membrane.
Indications of Hemofiltration
Advantages of Peritoneal Dialysis
It is easier to perform than hemodialysis or hemoperfusion and does not require anticoagulant.
Substances not amenable to significant extracorporeal removal include ……
Disadvantages of Peritoneal Dialysis
- However, it can be performed continuously, 24 hours a day,
- 24-hour peritoneal dialysis with dialysate exchange every 1-2 hours is approximately equal to four hours of hemodialysis.
Indications of Repeated Dose Activated Charcoal (Gut Dialysis)
Dose of Repeated Dose Activated Charcoal (Gut Dialysis)
Route of adminstration of Repeated Dose Activated Charcoal (Gut Dialysis)
It is given orally or via gastric tube
Types of Antidotes
- Antagonists
- Competitors
- Chelators
- Inactivators
Principle of action of Antagonist
- Substance which antagonizes action of the poison
Examples of Antagonists
Atropine
- antagonizes muscarinic action of organophosphate’s insecticides.
Pilocarpine
- antagonizes the peripheral action of atropine.
Principle of Competitors
- A substance which competes with poisons at sites of their action preventing them from exerting their effects.
- They are characterized by having similar chemical formula to poison.
Examples of Narcotic antidotes
- Naloxone (Narcan, N-ally) oxymorphine)
- Nalmefene (Revex)
- Nallorphine (N-allyl morphine, lethidrone)
Examples of Competitors
- Narcotic analgesics
- Ethyl Alcohol
Characters of Naloxone (Narcan, N-ally) oxymorphine)
- It acts as a pure antagonist.
- It is potent with no depressant action on CNS.
- It provides both a therapeutic & diagnostic modality for opioid poisonings.
Characters of Nalmefene (Revex)
- It acts as a pure antagonist.
Characters of Nallorphine (N-allyl morphine, lethidrone)
- It acts as agonist-antagonist
Characters of Ethyl alcohol as an antidote
- It is the antidote for methanol poisoning.
- It competes with the enzyme alcohol dehydrogenase, → so methanol doses do not change into toxic formaldehyde and formic acid.
Principle of Chelators
A substance which unites with the absorbed poison forming soluble less toxic and easily excreted complex.
Examples of Chelators
- All antidotes of heavy metals are chelators
Principle of Inactivators
A substance which unites with poison to form non-toxic complex
Examples of Inactivators
Hydroxocobalamin (Vil. B.12a): It unites with cyanide forming cyanocobalamin (Vit. B12).
Antidote of acetaminophen
N-Acetylcystoine (Mucomyst).
Antidote of anticholinergics
Physostigmine
Caution: may cause seizures, asystole, cholinergic crisis”.
Antidote of OCP (Anticholinestrases) & Carbamates
OCP
- Atropine
- Pralidoxime
Carbamates
- Atropine
Antidote of benzodiazepines
Flumazenil
Antidote of Beta-adrenergic blockers
Glucagon
Antidote of CO toxicity
- Oxygen.
- Hyperbaric O2 in severe cases.
Antidote of CCBs
Calcium chloride
Glucagon
Antidote of Digitalis
Fab antibodies (Digi-bind).
Antidote of Heavy metals
- BAL (dimercaprol), EDTA, Penicillamine, DMSA, Unithiol & DMPS
Antidote of Iron
Deferoxamine.
Antidote of Methemoglobinemia agents
Methylene blue.
Antidote of Methanol & Ethylene glycol
- Ethanol, Folate.
- Fomepizole.
Antidote of opiods
Naloxone.
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Antidote of warfarin & Super warfarin
Vit. K.
Def of the principle One pill can kill in children
- Drugs with potential for severe toxicity if one or two tablets ingested by a 10-kg toddler
Types of One pill can kill in children
Cardiac Indications for ICU Admission
- Cardiac arrhythmias.
- QRS duration > 0.12 s.
- Systolic BP < 80 mm Hg.
- Second or third degree atrioventricular block.
- Anticholinergic cardiac toxicity.
Indications for ICU Admission
For All Patients Who Present with Poisoning or Potential Exposure to A Toxic Substance
- Neurological
- Cardiac
- RESP
- Metabolic & Electrolytes
Neurological Indications for ICU Admission
- Toxin-induced seizures
- Unresponsiveness to verbal stimuli or Glasgow coma scale score ≤12.
Respiratory
Respiartory Indications for ICU Admission
- PaCO2 > 45 mm Hg.
- Need for endotracheal intubation
Metabolic & Electrolytic Indications for ICU Admission
Disposition of intoxicated patients
When to transfer the patient
we are DONE ✅
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