I just started Chantix 2 weeks ago and I’ve had some strange side effects.. I’ve been irritable, nauseas, and so tired. The scariest side-effect (I think that’s what it is) is my period is now 5 days late. I’ve taken two home pregnancy tests and both were negative. I’m almost certain these are Chantix side effects since my cycle is very, very predictable.
What we really need to know: Is Chantix responsible for skipped periods or false negative pregnancy tests? Thoughts from any medical experts would be greatly appreciated!
Answered by: Maria/MD Health Forum.com Team
Thanks for your question. Below are information about pregnancy tests and Chantix side effects:
During pregnancy, the body starts to produce a hormone called hCG (Human Chorionic Gonadotropin) which is the hormone detected by pregnancy test kits. The human chorionic gonadotropin (hCG) can be found in the blood or the urine. The hCG production starts when the embryo implants into the uterine lining and the amount of this hormone increases as the the pregnancy continues.
Home pregnancy tests are very accurate if done correctly, meaning reading the manufacturer’s recommendations before starting the test. The sensitivity of home pregnancy tests to hCH vary greatly. Some tests are sensitive to smaller amount of hcg like 20 mIU/ml, while others can only show positive pregnancy result when the detect hcg is over 100 mIU/ml. Home pregnancy tests can be positive as early as a couple of days before the missed period, but occasionally there are false negatives as implantation has not occurred yet. Many women won’t have a positive results until the first day of a missed period or even a few days later. For these reasons, women are advised to wait until the missed period before doing pregnancy tests.
First morning urine is the ideal sample for pregnancy testing because the it contains the most concentrated hCG. Women are advised against drinking water or other fluids in large quantities before using home pregnancy test kits as it may dilute the urine, and give inaccurate results.
Most drugs do not alter pregnancy tests results. Even if you are taking birth control pills or antibiotics, the results should be accurate as long as the test is done properly. However, those drugs that contain contain hCG or are used in combination with hCG such as Humegon, Pregnyl, Profasi, Pergonal, APL can affect the test results. Varenicline (Chantix) should not alter readings on pregnancy tests.
In some cases, home pregnancy test kits may give false positive results. This may occur in women who have tumors or other conditions that can result in the production of hCG.
If your pregnancy test was done at the right time and showed negative results, I’d recommend that visit your doctor to find out what’s the reason for your missed period. There are many possible causes of late periods, and based on what I’ve read, it is not among the reported side effects of Chantix. Common causes of late periods include stress, weight issues, and hormonal imbalance. Your health history and doctor’s assessment will help in identifying the underlying problem.
It is important for doctors to monitor the progress of patients who are taking Chantix especially during the first few weeks of use. Regular visits to the doctor is advised to determine how well the patient responds to the treatment, changes in the dose may be recommended if necessary. You mentioned that you have been experiencing irritability and tiredness since you have taken the drug, any person taking Chantix who are experiencing such symptoms are advised to contact their doctors immediately.
This blog entry is for your general information only. I recommend that you talk to your own doctor about your symptoms.
References:
http://www.drugs.com/chantix.html
http://www.pregnancy.org/
Weiss,R. 2004. The Everything Getting Pregnant Book: Professional, Reassuring Advice to Help You Conceive (Everything Series). Adam’s Media.
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