Preferred Sample Type


Suitable Specimen Types

  • Serum
  • EDTA Plasma
  • Li Hep Plasma
500 ul of serum/plasma

Specimen Transport


Sample Processing in Laboratory

Centrifuge and place in toxicology box in cold room.

Sample Preparation


Turnaround Time

3 working days

Sample Stability

4 ºC


General Information

Paroxetine (Paxil, Pexeva, Seroxat) is a serotonin reuptake inhibitor, belonging to a class of drugs which contains fluoxetine and sertraline and has been used since 1978 as an antidepressive agent. 

Adverse reactions for paroxetine include somnolence, agitation, tremor, insomnia, nausea and muscular weakness. Concurrent administration of a monoamine oxidase inhibitor may cause extreme agitation, muscle rigidity, hyperthermia, hypertension, delerium and coma (the serotonin syndrome). Hepatotoxicity may occur with therapeutic usage and severe neuroleptic malignant syndome has been described. Vertigo, nausea and comiting have been reported in patients following discontinuation of paroxetine therapy.

Patient Preparation

For TDM, sample should be taken prior to dose. If toxicity is suspected, take sample at earliest opportunity


Please avoid use of gel seperator tubes.

Reference Range

Toxicity associated with paroxetine levels > 0.35 mg/L.

Please contact the laboratory if paroxetine measurement is required for therapeutic monitoring purposes.

Paroxetine is measured by LC-MS/MS, as part of our Selective Serotonin Re-uptake Inhibitor (SSRI)  anti-depressant combined method.


  • EQA Scheme?: Yes

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HTA licence number is 12366

Protection of Personal Information – Laboratory Medicine comply with the Trust Data Protection Policy and have procedures in place to allow the Directorate and it’s employees to comply with the Data Protection Act 1998 and associated best practice and guidance.

The Trust Laboratories at Heartlands Hospital, Good Hope Hospital and Solihull Hospital were awarded UKAS (United Kingdom Accreditation Service) accreditation to the internationally recognised ISO 15189 standard in May 2015. For a list of accredited tests and other information please visit the test database
Tests not appearing on this scope are either under consideration or in the process of accreditation and so currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further information contact Louise Fallon, Quality Manager, 0121 424 1235