Preferred Sample Type


Suitable Specimen Types

  • Serum
  • EDTA Plasma
  • Li Hep Plasma
A minimum of 500 µl of plasma/serum is required.

Specimen Transport

First class post

Sample Processing in Laboratory

Place sample in toxicology rack.

Sample Preparation

None required

Turnaround Time

3 days.

Sample Stability

Keep refrigerated. 4 degrees.


General Information

Verapamil is a synthetic papaverine derivative, first introduced in 1962 as an anti-anginal agent. It has since been found to have anti-arrhythmic and anti-hypertensive properties, attributable to its ability to inhibit transmembrane calcium flux in excitable tissues. Daily adult oral maintenance doses range from 240 – 480 mg, while single i.v doses of 5 – 10 mg are used for hypertensive crises.

Adverse effects associated with verapamil administration include nausea, weakness, dizziness, bradycardia, hypotension and atrioventricular block. Intravenous calcium gluconate may be able to reverse cardiac toxicity observed. 

Patient Preparation

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


Verapamil measured by HPLC-DAD.

Reference Range

Therapeutic use of verapamil is associated with blood concentrations of up to 0.4 mg/L. Toxicity is associated with verapamil levels > 1 mg/L. (Schulz et al. Critical Care 2012, 16:R136).


  • 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