Chemical & Drug Injuries

Chemical & drug injuries

***All chemicals & drugs are capable of causing injury or death.***

accidental exposureself-administrationaccidental overdosenon-medical use of street drugsunanticipated result of self-administered or prescribed use

of standard medicines.exaggeration of an intended pharmacologic effect or an

accompanying side effect

Adverse drug reactions (ADRs)

any response to a drug that is noxious & unintended, occurring at doses used in humans for prophylaxis, diagnosis, or therapy, excluding failure to accomplish the intended purpose; [mechanisms: direct toxicity to cells; immunologic/idiosyncratic reactions; or due to ↓immunologic / hormonal host defenses]

Predictable ADRs: known side-effects; dose-related, severity depends on route of administration

Unpredictable ADRs: unanticipated, usually immunologic, idiosyncratic; dose & route of administration do not affect the severity

Therapeutic agents

ANALGESICS Aspirin Aspirin + Phenacetin NSAIDS (non-steroidal anti-inflammatory

drugs): Ibuprofen, Diclofenac, Acetaminophen/Paracetamol

ANTIMICROBIALSANTI-NEOPLASTIC AGENTS

Anti-metabolites Immunosuppressives

Therapeutic agents: aspirinTherapeutic dose: 0.5-1.0 gm./dayLethal dose: 2-4 gm./day in children

10-30 gm./day in adultsAcute toxicity: initial alkalosis--- fluid & electrolyte

imbalance--- metabolic acidosis--- deathChronic toxicity: (3 gm/day): dizziness, nausea, vomiting,

diarrhea, drowsiness, hallucinations, convulsions, comaKnown effects: analgesic; anti-platelet aggregation; gastric

irritant--- acute erosive gastritisUnpredictable ADRs: hypersensitivity: rashes, urticaria,

exfoliative dermatoses

Therapeutic agents: analgesics

Aspirin + Phenacetin Toxicity: nephropathy : renal papillary necrosis

NSAIDS: known side effect: gastric irritation; UADR: hypersensitivity

Acetaminophen: therapeutic dose: 0.5 gm q 4 hrs.(up to 3gm/day) toxic dose: 15-25 gm; toxicity: nausea, vomiting, diarrhea; shock;

hepatic injury pathology: hepatic necrosis; renal/myocardial

damage

Therapeutic agents: anti-neoplastics

Anti-metabolites Bone marrow suppression GI mucosal injury Hair follicle injury Immunosuppression Nonlethal mutations Initiation of some form of Cancer

Immunosuppressives ↑ susceptibility to infections, esp. opportunistic ↑ risk of malignant lymphoma

Therapeutic agents: antimicrobials/antibiotics

Hypersensitivity rashes, urticaria, exfoliative dermatoses anaphylaxis

Emergence of microbial resistance “super-infections”

Eradication of normal flora vitamin K deficiency--- bleeding

diathesis

Adverse drug reactions BLOOD (DYSCRACIAS)

Granulocytopenia Aplastic anemia Pancytopenia Hemolytic anemia thrombocytopenia

CNS Tinnitus, dizziness Acute dystonic

reactions Parkinson’s syndrome

CUTANEOUS Urticaria Petechia Exfoliative dermatitis

BLOOD DYSCRACIAS Anti-neoplastics Immunosuppressants Chloramphenicol Quinidine Methyldopa

CNS Salicylates Phenothiazine

antipsychotics Sedatives

CUTANEOUS Sulfonamides Hydantoin Anti-neoplastics

Adverse drug reactions CARDIAC

Arrhythmias Cardiomyopathy

HEPATIC Fatty change Cholestasis Hepatocellular

damage PULMONARY

Acute Pneumonitis Interstitial fibrosis Asthma

CARDIAC Theophylline Hydantoin Doxorubicin, Daunorubicin

HEPATIC Tetracycline Chlorpromazine,

Estrogens Halothane,

Acetaminophen, INH PULMONARY

Salicylates Nitrofurantoin Busulfan, Bleomycin

Adverse drug reactions

RENAL Glomerulonephritis Tubulointerstitial

nephritis Acute tubular

nephritis

SYSTEMIC Anaphylaxis Lupus

erythematosus syndrome

RENAL Penicillamine Phenacetin Salicylates Aminoglycosides,

Cyclosporine, Amphotericin B

SYSTEMIC Penicillin, Aspirin Hydralazine,

Procainamide

Fatal drug reactions

Tricyclic anti-depressants Alprazolam Ipramine,

Desipramine Nortriptyline

AcetaminophenHalothaneAspirin

CNS depression

Hepatic necrosisHepatic necrosisMetabolic acidosis; Fluid &

Electrolyte imbalance

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