Paxil and Weight Gain

paxil2Paxil (Paroxetine) is one of the most potent representatives of Selective Serotonin Reuptake Inhibitor (SSRI) group of antidepressants. Since it was approved long time ago, in 1992, it was used in treating major depression. Paxil is also considered to be highly potent in treating OCDs, panic disorders, numerous types of anxiety and generalized anxiety disorder to be exact. Like every drug, this one also has its side effects, where some are minor but some serious, so that change of therapy becomes a necessity. The most common side effects of Paxil are a headache, nervousness, restlessness, drowsiness, dizziness, nasal irritation, insomnia, nausea, constipation, weight changes, decreased sex drive, impotence, difficulty having an orgasm, dry mouth, yawning, or ringing in the ears. SSRIs (Selective serotonin reuptake inhibitors) generally don’t cause weight gain because the antidepressants boost serotonin, which helps you feel full. Paxil is an exception, causing a lot of people to avoid it.

How Does Paxil Cause Weight Gain?

Some researchers have found that using Paxil is altering your baseline metabolism causing it to slow down. Others are finding a connection between changed levels of serotonin, caused by this drug, and increased cravings for unhealthy food like simple carbohydrates.

Weight gain could be caused by:

  • Cravings: There were some reports that people taking Paxil were more prone to wanting unhealthy food in which the main ingredients are junk food, sugar, and other carbohydrates. There is an obvious link between carbohydrates and the secretion of the serotonin, but it is not yet concluded in which amount the Paxil plays a role.
  • Fat Storage: Paxil changes a person’s physiology, thus causing the metabolism of fat inside the body so the whole process of metabolism and storing the excess fat gets disrupted. In normal circumstances, the fat mechanism is functioning normal, so there must be a connection with the psychotropic drug.
  • Hormones: When taken over a long period of time, Paxil can cause hormonal imbalance. Since many hormones are in charge of fat processing and fat storage, the deficiency of some of those hormones can end up in weight gain.
  • Increased Appetite: A change of appetite is detected by many people who take Paxil. Depression causes people not to eat enough thus provoking a weight loss or remaining a low weight. When under the influence of the drug, some people feel better again and start taking better care of themselves, which can lead to eating adequate sized meals. More than needed, some people eat more than unusual while the drug gives them a significant uncontrollable appetite boost.
  • Metabolism: Since Paxil is capable of influencing the body’s metabolism, it can slow down the processing of the ingredients and it can lead to weight gain, even though some other factors are not present, such as unhealthy lifestyle.
  • Motivation: In certain individuals, Paxil causes motivation decrease. It makes them sedated, lazy, tired, not willing to be active, social or be outdoors. This can end up in not getting out of bed, being fatigue and not interested. This type of adverse effect can also lead to weight gain due to the fact that they don’t want to work on themselves and they are lacking the motivation to lead a healthy lifestyle.
  • Other Drugs: Some of the drugs used in combination with Paxil can markedly amplify weight gain. A specific example would be a combination of Paxil and Risperidone (an antipsychotic) together. This combination has been found to lead to an increase in weight of nearly 30 pounds in just 5 months of treatment. Researchers believe it is a result of a drug interaction that inhibits the CYP4502D6 enzyme.
  • Side Effects: Common side effects of Paxil are feeling of increased fatigue and sleepiness. As we mentioned above with lack of motivation, the lack of activity goes with it. Individuals who are on a Paxil therapy may experience tiredness and may not have the will to be active. The inactive life will usually lead to fat storage increase, even though the eating habits stay the same.
  • Social Eating: Depression and anxiety are causing people to avoid going out and eating with their friends or even with their family at home or outdoors. Social eating is normal among people who don’t have a problem with depression, anxiety and other motivation issues. They will want to stay home; they will be not interested in interaction with friends. When the drug for depression starts to act, this can lead to going out more, having bigger portions and can lead to weight gain.
  • Taste: Some antidepressants can alter our taste bud receptors causing the effect that food tastes better. We have mentioned above that the carbohydrate cravings may appear as a side effect of Paxil usage, but all foods may taste better.

Factors Linked to Weight Gain On Paxil

  • Combining Other Drugs: If weight problem arises, it is very important to take into consideration whether a person is simultaneously taking any other drug that may contribute to weight gain. Certain medications do have a tendency to cause weight gain – especially if they are psychiatric. In some cases, both drugs will synergistically promote weight increase.
  • Dosage: Minimal effective dose is the lowest dose of a drug that will cause the wanted effects with minimal risk of side effects. Doctor should start depression therapy with lower doses and titrate upwards until this minimal effective dose is reached. The main thing here to remember is the dosage will reflect in the drug’s effects. The less of the drug you are using, the lesser the drug will affect your body, thus will less likely lead to weight gain. It goes the same with the greater dosage, the greater the dosage of the Paxil, the greater the weight gain change.

Using a minimal effective dose of the drug decreases the probability of Paxil affecting your weight gain problem. In addition, your neurotransmitters alterations and the imbalance of your nervous system are more likely caused by higher drug doses than lower ones. This way homeostatic processes are more disrupted (i.e. hormones, baseline metabolism, the function of neurotransmitters, etc.) which all can result in weight gain.

  • Individual Factors: It is crucial to include all the individual factors which may influence the occurrence of other adverse effects and weight gain. In a number of cases, a person forgets to mention that his/her lifestyle has changed. A sudden stop doing daily exercise and living a healthy lifestyle sums into an unhealthy lifestyle followed by increased level of stress. It is important to take a look at your lifestyle and activity before analyzing all the effects that Paxil has since these can lead to the exact symptoms such as weight gain.
  • Time Span: In the early stages of treatment, Paxil may even cause a weight loss. The risk of weight gain increases as a period under the influence of this drug prolongs. As the time passes changes made on nervous system increase in number and that more likely leads to further increase in dosage used (leading to a further weight gain).

How Much Weight Will a Person Gain from Paxil?

Researchers and also pharmaceutical companies like to spread a work about drugs being weight neutral, which basically means there won’t be any weight change during the treatment on Paxil.  The evidence is somewhat unclear, but the studies have found that using Paxil can lead to increased weight when used on a long-term regime. The average of weight gain which a person can get, in the period of 6 to 12 months of use goes up to 24 lbs. This puts the Paxil in the group of one of the most affecting SSRIs in the area of weight change.

Who Will Gain Weight?

As previously already mentioned, in the initial stage of drug usage, some will notice a decrease in their weight number. Although many will end up getting a few pounds, it is crucial not to generalize this statement and to understand how many factors really do influence this whole process. This means that not every individual taking the Paxil as a therapy of choice will gain weight and end up in these symptoms.

Individual genetic as always plays a major role in the drug’s effects on the body and its results. There are tests developed such as GeneSight  which is used to test the genetic material and the way of drug effects on a person’s body during the interaction with genetic information. Putting it in general, duration and dosage used to play a major role, meaning that the persons which are on a short-term therapy and which have used a low dosage of drugs may not experience any weight change.

Cost-Benefit Analysis of Paxil

During the process of approving the drug for putting it on the market, one major thing taken in consideration is a cost-benefit relation. It is important that function of drug releases a patient from symptoms of disease at the same time causing a minimal number of side effects. This is exactly the same doctors do when considering prescribing a new drug for a patient. If you’re thinking of going for a certain medicine, you should consider the cons and pros with your doctor. The benefit should be the effectiveness of the drug, meaning the depression reduction and the unwanted adverse effects are something you should aim to get to a minimum. For a person with weight gain during the Paxil therapy, it is important to compare how much of gained weight is directly due to taking Paxil and then compare it to how effective this drug is in treating patient’s condition.

If the occurrence of weight gain gets significant and it is detected and the benefit from the medication is great, it is clear that treatment should be continued. On the other side, if the patient is not feeling like the drug is working and the effects are minor compared with the side effects while gaining weight, it is obvious that the drug does not work for that individual and he/she should withdrawal from it and ask for a drug replacement. The balance of benefit and side effects should be always in the favor of the benefits.

Prevention of Weight Gain

In order to prevent drug-related weight early intervention is the key. When prescribing antidepressants, it is important to provide informed consent and psychoeducation. Patients at metabolic risk should consider using weight-neutral or weight-loss agents and monitor for weight gain.  These patients have:

  • Abdominal Obesity (waist circumference > 40 inches [102 cm] in men, > 35 inches [88 cm] in women, or waist-to-hip ratio > 0 in men and > 0.9 in women)
  • Hyperlipidemia
  • Elevated Body Mass Index (BMI [overweight = BMI 25 to 30 kg/m2, obesity = BMI >30 kg/m2])
  • Hypertension
  • Diabetes Mellitus or Impaired Glucose Tolerance
  • History of Stroke or Cardiovascular Disease
  • Family History of Obesity, Hypertension, Diabetes, or Hyperlipidemia.

What to Do If Weight Gain Has Already Occurred?

The initial goal for patients is to lose 0.5% to 1% initial body weight per week—or 5% to 10% of weight across several months. Diet and exercise produce maximal benefit but require commitment and motivation, which are often difficult or impossible for depressed patients. Encouraging the patient’s efforts is worthwhile; if intervention is postponed until remission is achieved, weight gain may be substantially higher and more difficult to treat.


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