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Increased varenicline dose did not affect withdrawal symptoms, smoking cessation

Increasing the dosage of varenicline in smokers who had little initial response to the drug showed no substantial effect on their withdrawal symptoms, according to data recently published in JAMA Internal Medicine.

Researchers from London conducted a double-blind, randomized, placebo-controlled trial from July 2011 to February 2013 in a smoking cessation clinic. They aimed to determine whether increasing the dosage of varenicline in nonresponsive patients would improve the drug’s effectiveness. Smokers attending the clinic (n=503) began taking standard doses of varenicline tartrate 3 weeks prior to their target quit date.

Participants assessed their smoking enjoyment during the pre-quit period and their withdrawal symptoms for 4 weeks after their target quit date. After 10 days of treatment with varenicline, 200 participants were considered nonresponders and were randomly assigned to receive either more medication or placebo.

Varenicline and placebo doses were increased by 0.5 mg on days 12, 15 and 18, to a maximum of 5 mg/day. According to researchers, the dosage increase reduced patients’ smoking enjoyment, with mean ratings of 1.7 for varenicline vs. 2.1 for placebo (P=.001), prior to their quit dates. No significant differences were seen regarding a decrease in the rate of urge to smoke, or severity or strength of withdrawal symptoms. Similarly, the researchers reported the dose increases did not affect smoking cessation.

Varenicline was associated with higher rates of nausea (P<.001) and vomiting (P<.001) compared with placebo.

“Physicians often consider increasing the medication dose if there is no response to the standard dosage. Our results suggest that this approach may not work with varenicline,” the researchers wrote.

Disclosures: This study was supported by an investigator-initiated grant from Pfizer Inc. Pfizer Inc. supplied the study medication. Researchers reported receiving funding from and providing consultancy to manufacturers of smoking cessation medications, including Pfizer Inc., GlaxoSmithKline and McNeill Consumer Healthcare.