Before taking varenicline,
tell your doctor and pharmacist if you are allergic to varenicline or any other medications.
tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: anticoagulants (''blood thinners'') such as warfarin (Coumadin, Jantoven); insulin; other medications to help you stop smoking such as bupropion (Aplenzin, Forfivo, Wellbutrin, Zyban, in Contrave) and nicotine gum, inhaler, lozenges, nasal spray, or skin patches; and theophylline (Elixophyllin, Theo-24, Theocron). Your doctor may need to change the doses of some of your medications once you stop smoking.
tell your doctor if you have ever had withdrawal symptoms when you tried to quit smoking in the past and if you have or have ever had epilepsy (seizures); or heart, blood vessel, or kidney disease
tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking varenicline, call your doctor. If you are breastfeeding while taking varenicline, watch your baby carefully for seizures, and vomiting or spitting up more often that usual. Call your doctor immediately if your baby experiences any of these symptoms.
you should know that varenicline may make you drowsy, dizzy, lose consciousness, or have difficulty concentrating. There have been reports of traffic accidents, near-miss accidents, and other types of injuries in people who were taking varenicline. Do not drive a car or operate machinery until you know how this medication affects you.
you should know that some people have had changes in behavior, hostility, agitation, depressed mood, and suicidal thoughts (thinking about harming or killing oneself or planning or trying to do so) while taking varenicline. The role of varenicline in causing these mood changes is unclear since people who quit smoking with or without medication may experience changes in their mental health due to nicotine withdrawal. However, some of these symptoms occurred in people who were taking varenicline and continued to smoke. Some people had these symptoms when they began taking varenicline, and others developed them after several weeks of treatment or after stopping varenicline. These symptoms have occurred in people without a history of mental illness and have worsened in people who already had a mental illness. Tell your doctor if you have or have ever had depression, bipolar disorder (mood that changes from depressed to abnormally excited), schizophrenia (a mental illness that causes disturbed or unusual thinking, loss of interest in life, and strong or inappropriate emotions), or other mental illnesses. If you experience any of the following symptoms, stop taking varenicline and call your doctor immediately: suicidal thoughts or actions; new or worsening depression, anxiety, or panic attacks; agitation; restlessness; angry or violent behavior; acting dangerously; mania (frenzied, abnormally excited mood or talking); abnormal thoughts or sensations; hallucinations (seeing things or hearing voices that do not exist); feeling that people are against you; feeling confused; or any other sudden or unusual changes in behavior, thinking, or mood. Be sure that your family or caregiver knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own. Your doctor will monitor you closely until your symptoms get better.
ask your doctor about the safe use of alcoholic beverages while you are taking varenicline. Varenicline can increase the effects of alcohol,
ask your doctor for advice and for written information to help you stop smoking. You are more likely to stop smoking during your treatment with varenicline if you get information and support from your doctor.