L5: Salicylates Flashcards
what are Salicylates?
Salicylates are salts or esters of salicylic acid.
Forms of Salicylates in nature
Some derivatives are found in nature like methyl salicylate.
Common Preparations of Salicylates
- Acetyl salicylic acid (aspirin)
- Methyl-salicylate (oil of wintergreen)
Acetyl Salicylic acid (Aspirin)
- Available as lablets ranging from 75 mg for children to 325 mg for adults.
Methyl-Salicylate (Oil of wintergreen)
- It is a colorless or yellowish liquid which has a characteristic odor and taste.
- It is the most dangerous of salicylate formulations as one teaspoonful contains 7000 mg of salicylate.
Toxic action of Salicylates
- Local action
- Systemic action
Local toxic action of Salicylates
- Gastro-intestinal irritation
- Flaring up of peptic ulcer symptoms.
Systemic toxic action of Salicylates
- CNS effects
- Metabolic effects
- Hematological effects
- Hyperthermic effects
- Allergic effects
CNS effects of Salicylates
How do Salicylates Cause respiratory stimulation?
- Direct action on the brain.
- Indirect action by enhancing o2 consumption & cellular metabolic rate
what does resp. stimulation by Salicylates lead to?
- CO2 accumulation → hyperventilation → decreased PCO2 (respiratory alkalosis) → renal compensation by excreting more HCO3 and retaining more H+
Metabolic effects of Salicylates
Heamtologic effects of Salicylates
How do Salicylates decreases plasma prothrombin time?
- Direct hepatoloxicity, interfering with Vit.K utilization & inhibition of fact. VIl synthesis .
- Aspirin is transformed into dicoumarol which competes with Vit. K resulting in hypoprothrombinemia.
what causes Hyperthermic effects of Salicylates?
Due.to
- Enhancement of 02 consumption
- Cellular metabolic rate
- Dissociation of oxidative phosphorylation.
Allergic effects of Salicylates
- Skin rashes
- Hypersensitivity reactions
- Bronchospasm
- Angionerotic oedema
- Anaphylactic shock.
manner of poisoning by Salicylates
CP of Salicylates Toxicity
Acute or Chronic
CP of Mild Salicylate Toxicity
CP of Moderate Salicylate Toxicity
CP of Severe Salicylate Toxicity
Lethal Salicylate Toxicity
Coma & Death
what causes Chronic Salicylate Poisoning?
results from ingestion or application of large doses for long periods.
CP of Chronic Salicylate Poisoning
- Tinnitus
- Abnormal bleeding (gastric or retinal)
- Gastric ulceration
- Weight loss
- Mental deterioration
- Skin eruption
- May be liver damage
Investigations for Salicylate Toxicity
TTT aspects of Salicylate Toxicity
- Emergency and supportive measures
- Decontamination
- Antidote
- Enhanced elimination
emergency and supportive treatment of Salicylate Toxicity
Core of Airway, Breathing & Circulation.
Decontaminatio of Salicylate Toxicity
- Activated Charcoal
- Gastric Lavage
- Cothartic
Activated charcoal in Salicylate Toxicity
- Administration of activated charcoal to adsorb any remaining drvg.
Gastric Lavage of Salicylate Toxicity
- Gastric lavage using saline or water.
- It may be effective up to 12 hours.
Cathartic in Salicylate Toxicity
A saline cathartic may be given to hasten passage through the G.I.T
antidote in Salicylate Toxicity
- No specific antidote.
- NaHCO3 is given to prevent acidemia and promote elimination.
Enhanced Elimination of Salicylate
- Alkaline Diuresis
- Multiple Doses Activated Charcoal
- Hemodialysis
- Charcoal Haemoperfusion and MDAC
Alkaline diuresis of Salicylate Toxicity
- Correction of acidosis and alkalinization of urine with administration of sodium bicarbonate.
When is Alkaline diuresis of Salicylate Toxicity contraindicated?
- Pulmonary oedema,
- Impaired renal function
- Shock.
Multiple doses of activated charcoal for enhanced elimination
- To adsorb any remaining drug in stomach
- Interrupt entero-entric and entero-hepatic circulation
Hemodialysis Salicylates Toxicity
It effectively increases the clearance and improves fluid electrolyte balance.
It is indicated in
- Severe toxicity
- Cases of cardiac or renal failure.
Charcoal Hemoperfusion & MDAC in Alkaline diuresis of Salicylate Toxicity
They produce better salicylate clearance than haemodialysis.
Symptomatic Treatment in Salicylate Toxicity
