Overview

Varenicline is used in smoking cessation treatment by relieving the craving and withdrawal symptoms associated with stopping smoking. It can also reduce the enjoyment of cigarettes if patient continue smoking when on treatment¹.

Background of Safety Issue

The National Pharmaceutical Regulatory Agency (NPRA) has received information from the European Medicines Agency (EMA) on the risk of loss of consciousness associated with the use of varenicline. A review was initiated by the Pharmacovigilance Risk Assessment Committee (PRAC) following potential signal generated from EudraVigilance system and literature².

It is known that varenicline may cause dizziness or somnolence, and therefore may have minor to moderate influence on the ability to drive and use machines. However, till date, loss of consciousness has yet to be added as part of the precautionary statement in the European product package insert. Currently, PRAC is requesting the product registration holder of varenicline (Champix^®) to update the package insert to include information on loss of consciousness.

In Malaysia, there are currently two (2) registered products containing varenicline tartrate³. The package insert for these products contains information on somnolence and dizziness as reported side effects, but loss of consciousness is currently not included.

Adverse Drug Reaction Reports⁴

NPRA has received a total of 217 ADR reports with 374 adverse events suspected to be related to varenicline. The most reported adverse reactions were dizziness (45), followed by nausea (40), abnormal dreams (22) and headache (20). At present, there is one (1) report of depressed level of consciousness and one (1) report of loss of consciousness reported to the NPRA.

Advice for Healthcare Professionals

• Patients on varenicline therapy should be advised to exercise caution while driving or operating machinery until they know how varenicline may affect them.
• Please report all adverse events suspected to be related to varenicline to the NPRA.

References:

1. Malaysia Champix ® package insert. [Last revision date: September 2017]
2. European Medicines Agency (July 2018). PRAC recommendations on signals – Varenicline – Loss of consciousness.
3. The NPRA QUEST 3+ database [Accessed: July 2018]
4. The Malaysian Adverse Drug Reaction database, NPRA [Accessed: July 2018]

DISCLAIMER
This publication is aimed at health professionals. The information is meant to provide updates on medication safety issues, and not as a substitute for clinical judgement. While reasonable care has been taken to verify the accuracy of the information at the time of publication, the NPRA shall not be held liable for any loss whatsoever arising from the use of or reliance on this publication.