Scottish and Newcastle Anti-emetic Pre-treatment for Paracetamol Poisoning Study (SNAP)

• Status: Completed
• Trial end date: 2013-03-01
• Target enrollment: 0
• Participant gender: All

Summary

This study is designed to assess the impact of new approaches to therapy for paracetamol poisoning. Standard therapy is currently acetylcysteine by intravenous infusion over 20.25h. This regimen is given to those deemed "at risk" using standard criteria (British National Formulary 200920). It has 3 major problems, adverse events (nausea and vomiting and anaphylactoid reactions), therapy duration and complexity of administration.

This study is primarily designed to test the efficacy of prophylactic anti-emetic therapy.

It will also provide sufficient experience and data from a modified shortened IV acetylcysteine regimen to adequately design and power a study of the modified regimen as a new treatment for this common poison. Such an approach has a major potential to reduce patient adverse events from acetylcysteine therapy and shorten duration of hospital stay.

• Phase: Phase 4
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: University of Edinburgh
• Collaborators: Chief Scientist Office of the Scottish Government; NHS Lothian
• Treatments: Acetaminophen; Acetylcysteine; N-monoacetylcystine; Ondansetron

Criteria

Inclusion Criteria:

• Any patient admitted to hospital within 36 hours of a single acute paracetamol overdose; AND

• Requires treatment with acetylcysteine.

These patients will include:

• Patients with no risk factors and timed paracetamol concentrations above the 200-line on the UK paracetamol overdose treatment nomogram.

• Patients with at least 1 risk factor and timed paracetamol concentrations above the 100-line on the UK paracetamol overdose treatment nomogram

• Patients presenting >8 hours, and at risk of liver damage based on history of dose ingested (BNF) that need immediate treatment

Risk factors are defined as follows:

• Nutritional deficiency, malnourished and/or debilitating disease: acute or chronic starvation, eating disorders, cachexia, malabsorption syndromes, AIDS, cystic fibrosis, hepatitis C, chronic alcoholism.

• Enzyme induction: use of drugs with this property (carbamazepine, rifampicin, barbiturates, phenytoin, rifabutin, efavirenz, nevirapine, St John's Wort; regular consumption of ethanol above advised amounts.

Exclusion Criteria:

Patients:

• < 16 years old

• Detained under the Mental Health Act

• With known permanent cognitive impairment

• With a life-threatening illness

• Who are known to be pregnant

• Who have previously participated in the study

• Unreliable history of paracetamol overdose

• Vomiting and requiring treatment antiemetic prior to randomisation

• Presenting after 36 hours of a single acute paracetamol overdose

• Presenting after taking a staggered paracetamol overdose (defined as when the overdose of paracetamol is taken over a period of more than 2 hours)

• Who take anticoagulants (e.g. warfarin) therapeutically or have taken an overdose of anticoagulants

• Who, in the opinion of the responsible clinician/nurse, are unlikely to complete the full course of acetylcysteine e.g. expressing wish to self-discharge

• Who in the opinion of the responsible clinician/nurse are unable to complete the initial questionnaire either themselves or with nurse assistance.

• Who have a history of hypersensitivity to 5HT3 antagonists

• Non-English speaking patients. (Trial information material will only be produced in English in view of the known and stable demographic of the Edinburgh and Newcastle self harm population)