ADR, Management of drug poisoning.pdf

ADVERSE DRUG REACTIONS, MANAGEMENT OF DRUG POISONING (2024) ADVERSE DRUG REACTIONS, MANAGEMENT OF DRUG POISONING 1. Define adverse drug reaction (ADR) Undesirable adverse drug response is known as adverse drug reaction. 2. Differentiate Type A and Type B ADRs. Type A (Predictable) Type B (Unpredicta...

ADVERSE DRUG REACTIONS, MANAGEMENT OF DRUG POISONING (2024) ADVERSE DRUG REACTIONS, MANAGEMENT OF DRUG POISONING 1. Define adverse drug reaction (ADR) Undesirable adverse drug response is known as adverse drug reaction. 2. Differentiate Type A and Type B ADRs. Type A (Predictable) Type B (Unpredictable) Expected, adverse drug response Unexpected, adverse drug response Incidence rate is high Incidence rate is lower than Type A ADR Mortality rate is rare or very low Mortality rate is higher than Type A ADR Reduction in dose can minimize these Reduction in dose can’t minimize these adverse effects adverse effects 3. Describe the following terms with examples: a. Side effects - These are undesirable effects which are observed even with the therapeutic doses of the drug. These ADRs are usually mild and manageable. For example, Dicyclomine causes dryness of mouth at therapeutic doses (side effect). b. Toxicity - These are exaggerated form of side effects which occur predictably either due to overdoses or after prolonged use of the drug. The reason could be pharmacodynamic (Example- hyperpyrexia, hallucination with overdoses of atropine) or pharmacokinetic (Example, nephrotoxicity due to gentamicin in cases having renal insufficiency). c. Secondary effects - These are indirect consequences of the main Page 1 pharmacodynamics action of the drug. For example, development of Department of Pharmacology, Manipal University College Malaysia, Malaysia ADVERSE DRUG REACTIONS, MANAGEMENT OF DRUG POISONING (2024) superinfection after suppression of bacterial flora by antibiotics and weakening of host defences after the use of corticosteroids. d. Drug allergy - Allergic responses to drug occur when there has been previous exposure to drug (or its metabolites) and when this sensitised individual is re-exposed to the same drug again. Example, anaphylaxis after parenteral administration of penicillins. e. Idiosyncrasy - These are harmful and sometimes fatal reactions that occur in a small minority of individuals, for which the cause is yet poorly understood. Example, malignant hyperthermia due to drugs like halothane, succinylcholine. f. Iatrogenic disease - These are the diseases induced by drug therapy. These ADRs also occur when a drug is suddenly discontinued. Example, rebound hypertension after abrupt withdrawal of propranolol, peptic ulcer caused by aspirin. g. Mutagenicity - Genetic abnormalities caused by drug is known as mutagenicity. Example, Salmonella typhi cannot grow in a histidinedeficient culture medium. However, if a drug is a mutagen, it will induce mutation S. typhi. As a result the mutant strains of S. typhi can still grow even in the histidine- deficient medium. h. Carcinogenicity - Potential of drugs to cause malignancy is known as carcinogenicity. Example, Malignancy due to cyclophosphamide. i. Teratogenicity - These are impaired foetal developments due to drugs given to pregnant mother. Skeletal deformity in foetus because of administration of tetracycline to pregnant mother. j. Drug-induced photosensitivity - Phototoxic reactions in response to drugs is known as drug-induced photosensitivity. Example, Page 2 photosensitivity due to doxycycline. Department of Pharmacology, Manipal University College Malaysia, Malaysia ADVERSE DRUG REACTIONS, MANAGEMENT OF DRUG POISONING (2024) 4. Identify above adverse effects in a given clinical case. A 40 year old diabetic patient was diagnosed with Systemic Lupus Erythematosus (SLE). The doctor prescribed him glucocorticoids in addition to his antidiabetic medications. After, 30 days of glucocorticoids therapy his blood glucose level was raised. A. Identify the adverse effect in the above case. B. Why the patient’s blood glucose level was not controlled? 5. Describe drug dependence, physical and psychological dependence and withdrawal reaction. Drug dependence - A physiological state of neuroadaptation resulting from repeated administration of the drug, necessitating its continued use to prevent the appearance of distressing withdrawal syndrome which is manifested as opposite to the pharmacological effects of the drug. Physical dependence - It is an altered physiological state produced by repeated administration of a drug which necessitates the continued presence of the drug to maintain physiological equilibrium. It is characterized by intense craving for the drug, presence of invariable tolerance, severe and distressing withdrawal effects manifested by symptoms that are frequently opposite to those sought by the abuser. Psychological dependence - When the individual believes that optimal state of wellbeing is achieved only through the actions of the drug. Subject feels emotionally distressed if the drug is not taken. The intensity of psychological dependence may vary from desire to craving. Withdrawal effects - Adverse psychologic and physiologic reactions to an abrupt discontinuation of a dependence-producing drug and also Page 3 worsening of the clinical condition for which the drug was being used. Department of Pharmacology, Manipal University College Malaysia, Malaysia ADVERSE DRUG REACTIONS, MANAGEMENT OF DRUG POISONING (2024) 6. List various groups of drugs with examples which can produce dependence. Opioids- morphine Barbiturates- phenobarbitone Benzodiazepines- alprazolam Alcohol- ethyl alcohol 7. A 30 year old male patient was diagnosed from syphilis infection. The doctor prescribed him penicillin G injection to be given intramuscularly. Following 5 minutes of the first dose of injection, he developed flushing, swelling of lips, generalized itching, wheezing, palpitation followed by syncope. Choose appropriate measure to minimize ADR in the given clinical case. Measures to minimize ADR Proper medical history should be taken including allergy to any drug. In patients with history of asthma, allergic rhinitis, hay fever, etc., there is an increased risk of penicillin allergy, hence it should be avoided in such cases. If patient cannot recall then the drug must be tested for hypersensitivity at test dose before giving the therapeutic dose. Itching, erythema and wheal formation are watched for. Injection adrenaline and hydrocortisone should be kept ready before injecting penicillin. 8. Describe the various measures involved in the management of poisoning. General measures involved in the management of poisoning- GIT. Department of Pharmacology, Manipal University College Malaysia, Malaysia Page of poison has to be prevented by decontaminating the skin, eyes and 4 Decontamination of skin- For all poisoning cases, systemic absorption ADVERSE DRUG REACTIONS, MANAGEMENT OF DRUG POISONING (2024) Emesis- This is an effective way to evacuate gastric poisonous contents if given in an early stage (within 30 minutes of ingestion). However, it should be avoided in unconscious or convulsing patients and in those cases that have ingested petroleum products (danger of aspiration lipoid pneumonia), corrosive poisons (acid or alkali) or convulsant drug (strychnine). Gastric lavage- It is very effective for liquid or powder form of poison than for tablet or capsule and is very useful when started within 60 min of ingestion. Cathartics- These are also used to stimulate peristalsis. Example, 10% magnesium sulphate, 70% sorbitol Whole bowel irrigation- This utilises large volumes of balanced polyethylene glycol-electrolyte solution, to mechanically cleanse the entire intestinal tract. Respiratory and cardiovascular support Administration of antidote, if there is any. 9. Apply the concept of ionization and ion trapping in the treatment of drug poisoning. Aspirin (weak acid)→at acidic pH→gets unionized (lipid soluble). In aspirin poisoning, alkalinisation of urine is done by giving sodium bicarbonate which increases the pH. Thus, in this way aspirin at alkaline pH (increased pH) will get ionized (water soluble) and easily excreted. At alkaline pH, aspirin will be ionized, get trapped (Ion trapping) and easily Page 5 excreted out from body. Department of Pharmacology, Manipal University College Malaysia, Malaysia ADVERSE DRUG REACTIONS, MANAGEMENT OF DRUG POISONING (2024) MODEL QUESTIONS 1. Explain the following terms with suitable examples: a. Secondary effects b. Idiosyncrasy c. Iatrogenic disease d. Teratogenicity 2. List two groups of drugs with an example for each which can produce dependence. 3. Describe any four measures involved in the management of poisoning. Page 6 4. Explain why alkalinization is done in case of aspirin poisoning. Department of Pharmacology, Manipal University College Malaysia, Malaysia