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Lamictal and Birth Defects

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1. I am currently 7 weeks pregnant and have been taking Lamictal for the past three weeks. I am very concerned about the possibility of my baby being born with birth defects. My doctor put me on this medicine due to his diagnosis of possible bi polar disorder and complex post traumatic stress syndrome. I was also on several anti depressant medicines that did not work for me at all.

   I agreed to take this medicine because he put me on a gradual doses. The first two weeks I was on 25 milligrams and for the next two weeks I’m on 50 milligrams and after that 100 milligrams and so on until I’m on 200 milligrams. Does the fact that I’m doing it gradually reduce the risk of birth defects, or if I feel this concerned should I just refrain from taking it until after my first trimester?

   The only thing my doctor said was that there is no real medicine that is safe to take while I’m pregnant. He is concerned for my safety because I have extreme mood swings and get severely depressed. I have been feeling dizzy, short term memory loss, difficulty concentrating, short of breath, and very tired but it’s hard to tell weather these symptoms are caused by my pregnancy or the medicine.

   Your feedback would be greatly appreciated.

   

   Glenda Ruiz

   5 Aug 07 at 8:15 am
2. Hi Glenda:

   Your doctor is right – there is no “safe” medicine to take while pregnant. All antidepressants and psychotropic medications I’m aware of are at “pregnancy category C”, which according to the FDA means “Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.”

   I looked up the prescribing information (PI) for Lamictal, which states the following:

   Pregnancy Category C. No evidence of teratogenicity was found in mice, rats, or rabbits when lamotrigine was orally administered to pregnant animals during the period of organogenesis at doses up to 1.2, 0.5, and 1.1 times, respectively, on a mg/m2 basis, the highest usual human maintenance dose (i.e., 500 mg/day). However, maternal toxicity and secondary fetal toxicity producing reduced fetal weight and/or delayed ossification were seen in mice and rats, but not in rabbits at these doses. Teratology studies were also conducted using bolus intravenous administration of the isethionate salt of lamotrigine in rats and rabbits. In rat dams administered an intravenous dose at 0.6 times the highest usual human maintenance dose, the incidence of intrauterine death without signs of teratogenicity was increased.

   A behavioral teratology study was conducted in rats dosed during the period of organogenesis. At day 21 postpartum, offspring of dams receiving 5 mg/kg per day or higher displayed a significantly longer latent period for open field exploration and a lower frequency of rearing. In a swimming maze test performed on days 39 to 44 postpartum, time to completion was increased in offspring of dams receiving 25 mg/kg per day. These doses represent 0.1 and 0.5 times the clinical dose on a mg/m2 basis, respectively.

   Lamotrigine did not affect fertility, teratogenesis, or postnatal development when rats were dosed prior to and during mating, and throughout gestation and lactation at doses equivalent to 0.4 times the highest usual human maintenance dose on a mg/m2 basis.

   When pregnant rats were orally dosed at 0.1, 0.14, or 0.3 times the highest human maintenance dose (on a mg/m2 basis) during the latter part of gestation (days 15 to 20), maternal toxicity and fetal death were seen. In dams, food consumption and weight gain were reduced, and the gestation period was slightly prolonged (22.6 vs. 22.0 days in the control group). Stillborn pups were found in all 3 drug-treated groups with the highest number in the high-dose group. Postnatal death was also seen, but only in the 2 highest doses, and occurred between day 1 and 20. Some of these deaths appear to be drug-related and not secondary to the maternal toxicity. A no-observed-effect level (NOEL) could not be determined for this study.

   Although LAMICTAL was not found to be teratogenic in the above studies, lamotrigine decreases fetal folate concentrations in rats, an effect known to be associated with teratogenesis in animals and humans. There are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

   You are currently on less than half of the actual highest human dose recommended (500 mg). Granted, the above pregnancy data is in animals and not in humans, and data on the effect of Lamictal on pregnant women may only be available from the company. You may either call the company’s medical information and inquire about availability of this information, or ask your doctor to translate some of the above information from animal data if you want to find out more.

   Best wishes,
   Jane Chin

   

   Jane Chin, Ph.D.

   6 Aug 07 at 7:54 pm
3. Hi, When I read “highest human dose recommended (500 mg).” in the answer above, I get really worried. I now take 500 mg due to epilepsy, and my doctor said that if I will need to increase my dose in the future, 800 mg is the highest dose I can take of Lamictal. I am thinking of getting pregnant, but I guess that it is out of the question if I don’t decrease the dose?

   

   Eva Percy

   29 Mar 09 at 2:21 pm
4. Eva, if you are planning on becoming pregnant in the near future this is a crucial conversation you need to have with your physician.

   

   Jane Chin, Ph.D.

   25 Apr 09 at 10:53 am

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