|Drug Toxicity - clinical assessment
|Aspirin or Salicylates toxicity
|Ethylene glycol toxicity
|Carbon Tetrachloride Toxicity
|Renal Tubular Acidosis
|Tricyclic Antidepressant Toxicity
|Carbon monoxide Toxicity
|Paracetamol (Acetaminophen) toxicity
|Beta Blocker toxicity
|Calcium channel blockers toxicity
|Organophosphate (OP) Toxicity
|Toxin elimination by dialysis
|Drug Toxicity with Specific Antidotes
Mefenamic acid has important consequences in overdosage because it can cause convulsions
- Commonly available and may be seen in overdose
- Occasionally patients may take excess to manage pain
- Commonest are Ibuprofen and Mefenamic acid (Ponstan) often used for menstrual pain.
- Gastric irritation and mild abdominal pain.
- Mefenamic acid can famously cause seizures
- Overdose may also cause acute kidney injury and Metabolic acidosis
- Reduced GCS and drowsiness, nystagmus and tachycardia are rarely seen.
- Monitor U&E, LFTs and FBC.
- If reduced GCS place in the recovery position. Manage ABCs.
- Give activated charcoal 50 g if more than 10 tablets in the past 1-2 hours
- Manage ongoing seizures with IV/PR Diazepam and follow the usual treatment regimen. A single self-terminating seizure is managed conservatively managed
- Oral PPI e.g. Omeprazole may be given if there have been significant dyspeptic GI symptoms and manage any Upper GI haemorrhage as per usual protocol
- Most patients are medically fit for discharge by 12 hours if stable and no evidence of complication
- Psychiatric evaluation in all overdoses.
Do not prescribe nonsteroidal anti-inflammatory drugs (NSAIDs) to people with:
- Active gastrointestinal (GI) bleeding, or active GI ulcer or a history of GI bleeding related to previous NSAID therapy, or a history of GI perforation related to previous NSAID therapy or a history of recurrent GI haemorrhage (two or more distinct episodes), or history of recurrent GI ulceration (two or more distinct episodes).
- A history of hypersensitivity/severe allergic reaction to an NSAID (including Aspirin) for example, asthma, rhinitis, angioedema or urticaria.
- Severe heart failure.
- Severe hepatic impairment serum albumin less than 25 g/l or Child-Pugh score of 10 or more.
- Severe renal impairment eGFR less than 30 mL/minute/1.73 m2.
Do not prescribe COX-2 inhibitors, diclofenac, aceclofenac or high dose ibuprofen (more than 2400 mg daily) to people with:
- Ischaemic heart disease. Inflammatory bowel disease (COX-2 inhibitors only).
- Peripheral arterial disease or Cerebrovascular disease.
- CHF (New York Heart Association [NYHA] classification II-IV).
- Avoid etoricoxib or high dose ibuprofen to people with BP persistently above 140/90 mmHg
Prescribe NSAIDs with caution to people with:
- A history of peptic ulceration (standard NSAIDs are contraindicated), or people at high risk of GI adverse effects (for example, the elderly).
- Allergic disorders, Cardiac impairment, or heart failure as NSAIDs may impair renal function.
- Cerebrovascular disease, Coagulation disorders, Connective-tissue disorders.
- Hypertension as NSAIDs may impair renal function.
- Inflammatory bowel disease NSAIDs may increase the risk of developing or cause exacerbations of ulcerative colitis or Crohn's disease.
- Ischaemic heart disease or Peripheral arterial disease.
- Risk factors for cardiovascular events, for example, hypertension, hyperlipidaemia, diabetes mellitus, smoking.
- Hepatic impairment dose reductions may be necessary.
- Renal impairment (avoid if possible) sodium and water retention may occur leading to a deterioration in renal function and, possibly renal failure.
- If the person cannot avoid using an NSAID and has impaired renal function, monitor creatinine clearance or eGFR.
Also prescribe NSAIDs with caution in:
- Women trying to conceive NSAIDs may impair female fertility.
The elderly increased risk of cardiovascular, renal, and serious GI adverse effects (including GI bleeding and perforation, which may be fatal).