Talk about a heavy dose.
While the bulk of news coverage is focused on GLP-1 drugs like Ozempic that cause weight loss, licensed pharmacist Dr. Kati Forbes has spotlighted six medications “that’ll low-key or high-key make you fat or make you gain weight.”
Perhaps the most surprising is an over-the-counter drug that’s incredibly popular for allergic reactions.
1. Benadryl
Histamine, a chemical in our immune system involved in allergic response, also decreases appetite.
So, according to the Obesity Medicine Association, “it makes sense an antihistamine would have the opposite effect” and can “interfere with the ‘I’m full’ signal … and lead to overeating.”
Speaking to The Post, Forbes notes that first-generation antihistamines like Benadryl and cyproheptadine — which is also used as an appetite stimulant — can cause weight gain, particularly with long-term or continued usage.
2. Paroxetine (Paxil)
“Paroxetine (Paxil), an antidepressant, is one of the more sedating SSRIs (selective serotonin reuptake inhibitors) used for depression, anxiety/OCD etc.,” said Forbes.
SSRIs increase levels of the “feel-good” chemical serotonin in the brain, and Forbes calls Paxil one of the worst offenders when it comes to weight gain.
Forbes’s insights on the relationship between antidepressants and weight gain come amid growing antidepressant use, especially among young adults and teens.
One study found that about 14% of US adults take an antidepressant. The Harvard Pilgrim Health Care Institute (HPHCI) notes that people often stop using the drug if they experience weight gain.
Several psychiatrists in major New York hospitals told The Post they avoid prescribing Paxil as it causes more weight gain and sexual dysfunction than similar drugs — and has the worst withdrawal symptoms.
3. Mirtazepine
Mirtazapine, known by the brand name Remeron, is commonly prescribed to patients suffering from PTSD or insomnia. Those with major depressive disorder may be prescribed higher doses.
“We specifically try to avoid this in patients who are overweight,” explained Forbes. She noted that the same medicine is given to animals as an appetite stimulant to increase body weight.
Dr. James Kocsis, a professor and psychiatrist at Weill Cornell Medicine and NewYork-Presbyterian, previously told The Post that”Remeron (Mirtazapine) “is known to cause weight gain frequently because its anti-histaminic effect makes users sluggish.”
In a related TikTok, Forbes recommends trazodone as a better, less appetite-amplifying substitute.
4. Second-generation antipsychotics
Antipsychotics, also known as neuroleptics, are used to treat psychosis and schizophrenia. These meds are categorized into two classes — first-generation or “typical” antipsychotics and second-generation or “atypical” antipsychotics.
Forbes notes that second-generation antipsychotics, especially Zyprexa and Seroquel, can pump up the plump.
“The weight gain over a year can be massive, up to 30 to 50 pounds for some patients,” she said.
Antipsychotics affect neuropeptides, the signaling molecules associated with appetite control and food intake.
Within the antipsychotic drug class, Forbes notes that weight gain is linked to antihistamine activity and serotonin 2C antagonism.
“We have seven different types of serotonin receptors,” she said. “Specifically, 2C is where we get that side effect, the antagonism or blockade of that receptor.”
5. Dronabinol
Dronabinol is a synthetic THC used to treat and stimulate appetite in patients with chemotherapy-induced nausea and vomiting as well as address anorexia and weight loss in adult HIV/AIDS patients.
6. Insulin
“Insulin pushes glucose into cells vs the bloodstream,” Forbes expounds. “These are not to be confused with meds like Ozempic/Mounjaro/Trulicity etc which are not insulins but also injected and refrigerated.”
Insulin works by aiding the cellular absorption of glucose. However, when the cells absorb too much glucose, the body converts it into fat, leading to weight gain.
Forbes, who also makes lip balm and body butter, has previously shared the essential meds she keeps in her medicine cabinet to combat symptoms during cold and flu season and the surprising way you can repurpose ineffective stool softeners.
