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Lamictal & Weight Gain vs. Loss: What Should You Expect?

Lamictal (lamotrigine) is an anticonvulsant medication prescribed for the prophylaxis and/or management of epilepsy and bipolar disorder.  Research suggests that Lamictal modifies neurochemistry by: inhibiting voltage-gated sodium channels, blocking various calcium channels (L-type; N-type; P-type), antagonizing sigma and 5-HT3 receptors, upregulating GABA signaling, and suppressing the release of glutamate and aspartate.  Through the aforementioned mechanisms of action, Lamictal effectively prevents seizures and stabilizes mood.

While Lamictal is regarded as a highly effective anticonvulsant for the management of neurological disorders, and is even classified as an “essential medicine” by the World Health Organization (WHO), some prospective users may be concerned about its side effects – including body weight change – including weight gain and weight loss.  The good news for prospective Lamictal users is that, according to research, Lamictal is unlikely to cause significant weight change – and if weight change does occur, it’s most likely to be modest weight loss.

Does Lamictal cause weight loss or weight gain? (And if so – how much?)

Based upon available medical research, Lamictal is likely to have no clinically significant effect on body weight.  Moreover, if Lamictal does impact weight, it’s most likely to induce weight loss (rather than cause weight gain).  Among persons who are prone to experiencing weight loss on Lamictal, research indicates that average weight loss ranges from: 2.58 lbs. to 9.25 lbs. – and obese users appear to lose more weight than non-obese users.

There’s no substantial evidence to suggest that Lamictal causes weight gain.  The most weight gain reported in a clinical trial participant receiving Lamictal was ~2.2 lbs. (1 kg), and the highest average weight gain in a single trial was 0.68 lbs.  In short, Lamictal users are unlikely to experience weight gain as a result of treatment, and if weight gain occurs, it probably won’t be significant.

Lamictal & Weight Change: Gain vs. Loss (Hypothetical Causes)

In the event that you experience weight change (gain or loss) while using Lamictal, included below is a list of possible reasons for that change.  Understand that a majority of evidence suggests that Lamictal is unlikely to cause clinically significant weight change (defined as 7% body weight change from baseline).  Nevertheless, evidence is based upon average responses to the medication – and does not account for individual variability in reactions.

For this reason, it’s possible that you could be an outlier and end up experiencing significant weight change on Lamictal.  Potential and/or hypothetical causes for weight change on Lamictal include: appetite change; gastrointestinal reactions; hormone fluctuations; changes in energy level; altered taste perception; and/or shifts in resting metabolic rate.  That said, it is important to keep in mind that the cause(s) of one person’s weight change on Lamictal might differ from the cause(s) of another’s.

  • Appetite changes: You might experience changes in appetite while using Lamictal such that your appetite significantly increases or decreases – compared to baseline. If you experience an increase in appetite, it may be difficult to restrain yourself from consuming excess calories – whereby you might gain weight.  Oppositely, if you experience a reduced appetite or appetite loss – you might have difficulty eating sufficient calories to maintain weight – ultimately causing weight loss.
  • Bipolar symptoms: Bipolar disorder is a condition that can cause changes in neurophysiology, as well as weight. Individuals in a manic or hypomanic phase of bipolar disorder might exhibit faster metabolism, increased physical activity, and/or feel less hungry than usual – causing weight loss.  On the other hand, it may become easier to pack on weight during a depressive phase of bipolar disorder.  This considered, some of the weight change on Lamictal might be due to stabilization of mood – shifting out of a manic/hypomanic or depressive phase.
  • Change in energy level: The mechanism of action associated with Lamictal is understood to decrease excitatory neurotransmission and increase inhibitory neurotransmission. This combination may cause drowsiness or fatigue in some persons.  That said, if you were depressed prior to using Lamictal – this mechanism might actually increase your energy level.  Changes in energy might affect your physical activity level and could influence body weight via energy expenditure.
  • Cognitive impairment: The inhibitory action of Lamictal might cause mild (or perhaps substantial) cognitive impairment in a subset of users. Changes or impaired cognitive function might decrease self-regulation (i.e. willpower) around food – and could lead to overeating.  Cognitive deficits might also make it more difficult to plan healthy meals or decrease motivation to eat healthy – which could cause weight gain.  Oppositely, cognitive impairment might cause other individuals to forget to eat enough.
  • Food cravings: A subset of Lamictal users may experience food cravings as a side effect. Though this isn’t a common side effect, food cravings could occur due to a unique interaction between the drug’s effect and a user’s neurochemistry.  If you experience food cravings, it’ll probably be challenging to resist eating extra calories than you did prior to using Lamictal.  Extra calories consumed throughout treatment vis-à-vis food cravings will cause weight gain.
  • Hormone changes: It’s possible that Lamictal might affect concentrations of various hormones over the long-term. While short-term studies suggest that Lamictal doesn’t substantially alter sex hormones like testosterone and estrogen, some speculate that it might decrease sex hormone concentrations over a longer-term.  If it is capable of reducing circulating sex hormone levels, then perhaps this would unfavorably affect body composition via increasing fat storage and decreasing muscle synthesis.
  • Gastrointestinal reactions: Lamictal can cause a host of gastrointestinal reactions including: constipation, diarrhea, and flatulence. As a result of these gastrointestinal reactions, you may end up experiencing weight change.  For example, if you become constipated, your body is probably retaining more weight than usual in the form of digested food – this might explain your weight gain.  Contrarily, if you develop diarrhea, this reaction might explain your weight loss.
  • Metabolism shift: There’s a chance that Lamictal could alter your metabolic rate from homeostasis. In the event that Lamictal speeds up your metabolism (compared to pre-treatment) you might end up losing some weight due to increased energy expenditure.  Conversely, if Lamictal slows your metabolism (compared to pre-treatment), you might gain some weight as a result of decreased energy expenditure.
  • Nausea or vomiting: Though generally transient and fairly uncommon, some Lamictal users might end up experiencing nausea and/or vomiting as adverse effects. If you’re constantly nauseous – this nausea may interfere with your appetite or dissuade you from eating (due to the fact that you don’t want to vomit).  In the event that you actually vomit, this could certainly account for some weight loss – due to fewer calories being absorbed and dehydration.
  • Social eating: If prior to using Lamictal you had unmanaged neuropsychiatric symptoms, there’s a chance that these symptoms caused you to isolate yourself from others. For example, if you experienced severe depression prior to using Lamictal – you probably weren’t doing much socializing.  In the event that Lamictal helps get your symptoms under control, you may start socializing more frequently – and engaging in social eating (going out to eat with others).  Because foods at most restaurants tend to be high in calories and large in terms of size – this could lead to some weight gain.
  • Taste perception adjustment: When taking Lamictal, some individuals will experience changes in taste perception. Anecdotes report that Lamictal leaves a metallic taste in the mouth and causes food to taste bitter or bland.  If food doesn’t taste as good as usual during treatment, this could lead some individuals to eat fewer calories than usual – leading to weight loss.  On the other hand, if Lamictal somehow enhances your taste – it might cause weight gain.

Lamictal & Weight Change: The Research

Included below are trials and/or reports in which the effect of Lamictal on body weight was evaluated or discussed.  As you’ll read, none of the available data indicate that Lamictal causes weight gain.  Most evidence suggests that Lamictal has no significant effect on body weight (i.e. is “weight neutral”), and some evidence supports the idea that Lamictal may cause weight loss.

2013: Weight change associated with antiepileptic drugs.

Pickrell, Lacey, Thomas, et al. sought to determine the effect of frequently-prescribed antiepileptic medications on the body weights of users.  The aforementioned researchers conducted a retrospective observational analysis with electronic primary healthcare records from over 1 million adult patients in Wales – all of whom were over the age of 18 and diagnosed with epilepsy.  The body weights of all patients had been recorded prior to antiepileptic treatment, as well as for a period of 3 to 12 months after treatment initiation.

Researchers then calculated patients’ body weight changes from baseline as a result of antiepileptic use.  Results indicated that lamotrigine (i.e. Lamictal) users exhibited no significant changes in body weight.  Average weight changes as a result of lamotrigine administration ranged from -0.38 kg to +1 kg – for an overall average of +0.68 lbs. (0.31 kg).

  • Source: https://www.ncbi.nlm.nih.gov/pubmed/23236017

2009: Lamotrigine in the treatment of binge-eating disorder with obesity: a randomized, placebo-controlled monotherapy trial.

Guerdjikova, McElroy, Welge, et al. conducted a study to investigate the safety and effectiveness of Lamictal for the treatment of binge eating disorder (BED) associated with obesity.  A total of 51 individuals were recruited to participate in this study, all of whom had met diagnostic criteria for binge eating disorder (in accordance with the DSM).  Participants were randomized to receive either lamotrigine (26) or a placebo (25) for a 16-week duration in a double-blind, flexible-dose trial.

Although lamotrigine (~236 mg/day) and placebo were of similar efficacy in decreasing the weekly number of binge eating episodes and binge days, lamotrigine recipients lost more weight (-1.17 kg) compared to placebo recipients (-0.15 kg).  What’s more, lamotrigine recipients exhibited substantial reductions in fasting glucose, insulin, and triglycerides.  Though this was a very small-scale study, it supports the idea that Lamictal could cause weight loss of ~2.58 lbs. over a 4-month span.

  • Source: https://www.ncbi.nlm.nih.gov/pubmed/19357528

2007: Effectiveness and weight effects of open-label lamotrigine with and without concomitant psychotropic medications in patients with bipolar I disorder.

Zarzar, Graham, Roberts, et al. evaluated the effect of lamotrigine on body weight among persons diagnosed with bipolar 1 disorder.  Specifically, researchers sought to determine how lamotrigine impacts weight when administered as a standalone, as well as when administered concurrently with another medication.  For the study, researchers conducted a post-hoc analysis of data from a 12-week open-label study comprised of 1175 patients (with bipolar 1 disorder) using lamotrigine to treat symptoms.

The open-label study included a 5-week titration phase with a target dose of lamotrigine set at 200 mg per day.  Data from the study revealed no changes in body weight or BMI associated with lamotrigine treatment – regardless of whether administered as a standalone or adjunct (with valproate, antipsychotics, lithium or antidepressants).  It was concluded that lamotrigine was safe, effective, and well-tolerated by patients.

  • Source: https://www.ncbi.nlm.nih.gov/pubmed/17955096

2006: A single-center, double-blind, placebo-controlled evaluation of lamotrigine in the treatment of obesity in adults.

Merideth noted that, unlike most mood stabilizers, lamotrigine isn’t associated with weight gain.  Because lamotrigine doesn’t generally cause weight gain, Merideth organized a trial to determine the effectiveness of lamotrigine compared to placebo for the induction of weight loss among adults with obesity.  A total of 40 individuals were recruited to participate in the trial and randomly assigned to receive either: lamotrigine (200 mg per day) or a placebo – for a 26-week span.

The body weights, BMIs, body fat percentages, serum lipids, and glycosylated hemoglobin levels of participants were recorded at baseline – and compared to measures following week 26.  Average change in body weight from baseline was -6.4 lbs. for the lamotrigine recipients, and -1.2 lbs. for the placebo recipients.  The BMIs of lamotrigine recipients decreased by 1.5, whereas the BMIs of placebo recipients decreased by just -0.1.

It was concluded that lamotrigine may significantly decrease BMI and reduce body weight among individuals with obesity.  Moreover, lamotrigine users were satisfied with the medication and reported no significant unwanted side effects.  Although this was a relatively small study, it supports the idea that lamotrigine may cause weight loss.

  • Source: https://www.ncbi.nlm.nih.gov/pubmed/16566621

2006: Impact of lamotrigine and lithium on weight in obese and nonobese patients with bipolar I disorder.

Bowden, Calabrese, Ketter, et al. assessed the effect of lamotrigine and lithium on body weight of obese and non-obese patients with type-1 bipolar disorder.  Researchers conducted a post-hoc analysis of data from multiple 18-month double-blind, placebo-controlled trials consisting of 155 obese and 399 non-obese patients.  The patients received either: lamotrigine, lithium, or a placebo for the 18-month duration.

Results noted that individuals with obesity exhibited: weight loss of 9.25 lbs. (4.2 kg) with lamotrigine treatment; weight gain of 13.44 lbs. (6.1 kg) with lithium treatment; and weight loss of 1.32 lbs. (0.6 kg) with placebo.  Non-obese patients exhibited: weight loss of 1.1 lbs. (0.5 kg) with lamotrigine; weight gain of 2.42 lbs. (1.1 kg) with lithium; and weight gain of 1.54 lbs. (0.7 kg) with placebo.  This study supports the idea that lamotrigine treatment facilitates weight loss – particularly among those with obesity.

  • Source: https://www.ncbi.nlm.nih.gov/pubmed/16816224

2006: Effects of lamotrigine and lithium on body weight during maintenance treatment of bipolar I disorder.

Sachs, Bowden, Calabrese, et al. retrospectively analyzed the impact of lamotrigine treatment on body weight of persons with bipolar disorder.  Data for the retrospective analysis was derived from multiple double-blind, placebo-controlled, 18-month trials testing lamotrigine and lithium for the management of bipolar disorder.  In the trials, a total of 227 patients received lamotrigine, 166 received lithium, and 190 received a placebo.

Results indicated that lamotrigine recipients exhibited no significant change in body weight; weight remained stable throughout the 18 months.  An analysis by researchers determined that, on average, lamotrigine users exhibited an average weight loss of 2.64 lbs. (1.2 kg) over a 52-week span.  It was further stated that 12.1% of lamotrigine recipients exhibited clinically significant weight loss as a result of treatment.  Researchers concluded that lamotrigine’s effect on body weight is analogous to that of a placebo.

  • Source: https://www.ncbi.nlm.nih.gov/pubmed/16542188

2005: Drug-induced weight gain.

Ness-Abramof and Apovian published a paper discussing drug-induced weight gain.  In the paper, the authors state that weight gain is a problematic side effect of many pharmaceutical medications in that increased body weight often compromises health of the user – and frequently interferes with treatment compliance.  Authors briefly discuss the fact that many neuropsychiatric medications, including: antipsychotics, antidepressants, and mood stabilizers –induce weight gain.  That said, it was further mentioned that lamotrigine appears to be weight neutral.

  • Source: https://www.ncbi.nlm.nih.gov/pubmed/16234878

2004: Safety and tolerability of lamotrigine for bipolar disorder.

Bowden, Asnis, Ginsberg, et al. reviewed data from 8 placebo-controlled clinical trials (comprised of 1800 participants) and 4 unpublished studies in which lamotrigine was administered to treat bipolar disorder.  Researchers assessed the data to determine whether lamotrigine was safe, effective, and tolerable among individuals with bipolar diagnoses.

Of the 1800 trial participants, 827 received lamotrigine as a monotherapy or adjunct for an 18-month duration.  It was noted that lamotrigine was well-tolerated and unlikely to cause adverse reactions.  Results from this review indicate that lamotrigine does not appear to cause weight gain – even when administered for an extended duration.

  • Source: https://www.ncbi.nlm.nih.gov/pubmed/14756579

Variables that influence Lamictal-mediated weight change

There are a myriad of possible variables that could influence someone’s likelihood of experiencing weight change while using Lamictal (i.e. lamotrigine).  Variables that may be most likely to influence weight change among Lamictal users include: baseline weight (body weight prior to using Lamictal); adjunct substance use; Lamictal dose; duration of Lamictal use; prior medication use; and/or lifestyle/genetics of the user.

  1. Baseline weight: Your body weight before using Lamictal may determine the amount of weight change that you experience throughout treatment. Research suggests that persons who are obese tend to experience greater total weight loss while using Lamictal than individuals who aren’t obese.  One study showed that obese individuals lost an average of over 9 lbs. during Lamictal treatment whereas non-obese persons lost just over 1 lb.  Based on this evidence, it’s reasonable to speculate greater weight loss on Lamictal among persons with preexisting obesity.  If you’re already at a relatively normal body weight – your weight may be less likely to fluctuate as a result of treatment.
  2. Adjunct substance use: Though Lamictal can be used as a monotherapy (or standalone medication), some individuals may administer Lamictal along with other substances. Substances that might be prescribed along with Lamictal (as adjuncts) include: antidepressants, antipsychotics, and mood stabilizers.  Furthermore, some individuals using Lamictal might concurrently administer dietary supplements and/or over-the-counter medications.  If you’re administering other substances with Lamictal, there’s a chance that the other substance(s) might also be culpable for some of – or all of – your weight change (or lack of weight change).
  3. Lamictal dose: Research of Lamictal does not suggest that certain dosages are more likely to facilitate weight change than other dosages. However, the lower the dosage of Lamictal that’s administered, the less substantial it’s neurophysiologic impact will be.  Assuming Lamictal induces weight loss, higher dosages might amplify the underlying neurophysiologic mechanisms associated with weight loss induction – thereby yielding greater weight loss at high doses (compared to lower ones).
  4. Duration of Lamictal use: For certain individuals, the total duration over which Lamictal has been regularly administered might impact weight change. For example, some users might not notice any weight change in the early stages of treatment due to the fact that the body hasn’t yet fully adapted to the influence of Lamictal – or due to the fact that users are still titrating their dosage upwards to a therapeutic level.  However, these same individuals may notice weight change with continued administration (e.g. weight loss after several months).  That said, other persons might experience noticeable weight loss in the early stages of treatment followed by weight stabilization and maintenance.
  5. Previous substance use: Previously used medications and/or supplements could give the false impression that Lamictal treatment is dramatically altering your body weight. For example, if you previously used a medication associated with weight gain (e.g. lithium) – and gained 10 lbs. during treatment, then you transition to Lamictal and lose weight, you cannot assume that all of the weight loss is from Lamictal.  Some of the weight loss may be due to the fact that you’re no longer using a mediation associated with weight gain – and your body weight reverted back to homeostasis following cessation of the previous drug.  (The opposite also applies: If you were using a medication that caused significant weight loss and gain weight while using Lamictal – the gains may be more attributable to homeostatic reversion than Lamictal treatment).
  6. Lifestyle & genetics: The combination of your lifestyle and genetics might influence the amount of weight change you experience while using Lamictal. Someone who makes a conscious effort to track his/her calories and exercise regularly might find that it’s easier to lose weight on Lamictal than before, whereas an individual who consumes mostly hyperpalatable “junk” food and lives a sedentary lifestyle during treatment may gain weight.  Moreover, it’s possible that your gene and epigenetic expression might interact with Lamictal to influence likelihood of weight change throughout treatment – and the significance of weight change if it occurs.

Possible ways to minimize Lamictal-related weight change

Understand that most Lamictal users do not experience clinically-significant weight change (characterized by body weight change of at least 7% from baseline).  That said, if you are concerned about body weight change while using Lamictal – or have already experienced weight change, below are some weight management strategies to consider implementing.  Always talk to your doctor to verify the safety of these weight management strategies before testing.

  1. Monitor diet & exercise: Because most people do not regularly track calories and exercise – it’s unlikely that most Lamictal users critically monitor diet and exercise habits. Because weight change can be attributable to calorie intake and exercise – you may want to make a habit of tracking these influencers if you’re experiencing weight change on Lamictal.  If you’re losing weight – it could simply be because you’re eating less or exercising more (irrespective of the medication’s influence).  Adjusting your caloric intake and exercise frequency might help mitigate undesired weight change on Lamictal.
  2. Tweak Lamictal dosage: Though it’s unclear as to how Lamictal dose affects body weight, it is common sense to assume that the greater the dose – the greater the neurophysiologic impact of the medication. This considered, it’s reasonable to hypothesize that higher doses of Lamictal might yield greater weight change than lower doses.  If you want to minimize weight fluctuations on Lamictal – work with your doctor to find the minimal effective dose (or lowest concentration needed to treat symptoms).
  3. Treat side effects that induce weight change: If you’re experiencing unwanted weight change due to certain side effects of Lamictal, ask your doctor whether those particular side effects can be treated. For example, if you’re losing weight due to appetite suppression – ask your doctor whether there’s anything that can be done to help improve your appetite.  Similarly, if you’re gaining weight due to fatigue, ask your doctor about augmentation options to bolster energy.
  4. Concurrent substance considerations: Anyone who experiences unwanted weight change while taking Lamictal should reflect upon the concurrent substances that they’re using. For example, if you’re taking medications and/or supplements with Lamictal – ask your doctor and/or investigate whether those agents might be culpable for your weight change.  Some individuals may notice that unwanted weight change abates when medically-unnecessary substances are discontinued.  On the other hand, if you’re not using any substances with Lamictal – you may want to use another agent to help counteract unwanted weight change.
  5. Longer-term Lamictal use: Unwanted weight fluctuations can sometimes occur in early phases of Lamictal treatment – followed by long-term stabilization. If you’re in the early stages of treatment and are dissatisfied with weight change – consider sticking it out for a while longer and reassessing whether body weight normalizes with longer-term use.

Note: If you experienced substantial unwanted weight change while using Lamictal, and none of the above-mentioned weight management strategies are helpful, you may want to discuss the idea of Lamictal withdrawal and/or switching to another medication – with your doctor.

Have you experienced weight loss or weight gain from Lamictal?

If you ended up experiencing weight loss or weight gain while using Lamictal, document the specific amount of weight change that you experienced in the comments section below.  Although studies provide averages for how much weight individuals lose or gain throughout trials – they do not account for individual variation.  For this reason, you might end experiencing much more substantial weight change on Lamictal than what’s considered “average.”

To help others fully understand the details associated with your Lamictal use, mention things like: how long you’ve used Lamictal; your Lamictal dosage; whether you use other substances with Lamictal; and whether you are currently underweight, overweight, or obese.  Assuming you’ve been using other substances with Lamictal – are you sure that those other agents aren’t contributing to your weight change?  Moreover, if you’ve gained or lost weight from Lamictal – what do you think the reasons are for the weight change? (e.g. appetite change; faster metabolism; increased energy; etc.).

After you began taking Lamictal, how long did it take for you to notice a change in body weight?  Did your weight change occur within a short-term followed by stabilization – or did the weight change occur gradually over a longer-term?  Did you track calories and physical activity throughout Lamictal treatment to verify that the weight change you experienced wasn’t simply due to altered energy intake or expenditure?

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