Obesity

Sonya Collins

In February, Eisai removed the weight-loss drug lorcaserin (Belviq, BelviqXR) from the market at FDA’s request. The request cited a safety clinical trial that found an increase in cancer incidence among people who take the medication. Lorcaserin’s removal leaves behind multiple options in several drug classes.

Appetite suppressants

Several prescription weight-loss medications—phentermine, benzphetamine, diethylpropion, phendimetrazine, and others—increase chemicals in the brain that curb the appetite.

“These drugs curb the appetite while stimulating the release of catecholamines, norepinephrine, dopamine, or serotonin, so that you feel good as well,” said Laura Shane-McWhorter, PharmD, CDCES, professor (emeritus) clinical, University of Utah College of Pharmacy, Salt Lake City.

But these drugs are not for people who have heart disease, uncontrolled hypertension, hyperthyroidism, or glaucoma. They also may not be appropriate for patients who have severe anxiety or other mental health conditions. They should not be combined with MAOIs.

GLP-1 agonists

High-dose liraglutide (Saxenda—Novo Nordisk), said Shane-McWhorter, “stimulates the release of insulin from the pancreas, slows down gastric emptying, and sends a message to the satiety center in the brain so that the person feels full.”

But it isn’t safe for people with a history of thyroid tumors, pancreatitis, hepatic impairment, gall bladder disease, or gastroparesis. “And many patients with diabetes do have gastroparesis,” said Shane-McWhorter. After starting the drug, patients may need to adjust the dose of any secretagogues.

Lipase inhibitors

Orlistat is available in prescription (Xenical—Roche) and OTC (Alli—GlaxoSmithKline) strengths. The lipase inhibitor restricts the amount of fat that the gut can absorb from food.

“So, if you eat fat while you take this medication, you pay with side effects,” Shane-McWhorter said. Rather than absorb the fat, the body moves it out in the form of diarrhea and leaky stools that may involve abdominal pain, bloating, and gas. “It’s thought,” Shane-McWhorter added, “that this side effect may help some patients change those eating behaviors—although many patients give up.”

Patients should take a daily multivitamin that includes vitamins A, D, E, and K while taking this medication to help compensate for the nutrients they may no longer absorb from food. Orlistat isn’t right for people who have chronic malabsorption issues or gallstones.

The drug may prevent absorption of drugs that have a narrow therapeutic index, such as warfarin, cyclosporine, and levothyroxine.

Combination medications

Phentermine-topiramate combines the appetite-suppressing phentermine with the anticonvulsant topiramate. The latter, which acts on gamma-aminobutyrate and voltage-gated ion channels, may help people feel less hungry or fuller than usual after a typical meal.

Like phentermine alone, this drug isn’t for people who have hyperthyroidism or glaucoma or who take MAOIs. It also may not be safe for people who have had a heart attack or stroke or have abnormal heart rhythm, kidney disease, or mood problems. The drug can also cause birth defects.

Naltrexone-bupropion, an opiate agonist and a nonadrenergic/dopaminergic antidepressant, acts on the brain’s reward center to curb appetite and block the reward sensation that results from eating.

This medication isn’t suitable for people who have uncontrolled hypertension, seizures, or a history of anorexia or bulimia. Patients who are dependent on opioids or who are withdrawing from drugs or alcohol also shouldn’t take this medication. Patients shouldn’t take it in combination with the antidepressant bupropion (Wellbutrin, Zyban—GlaxoSmithKline). Finally, the drug comes with a warning for the risk for suicidal thoughts or actions.

This drug may interact with medications metabolized by CYP2D6 and B6. Pharmacists should carefully review the patient’s medication list.

Weight-loss counseling

When counseling patients on weight-loss drugs, it’s crucial to include one caveat: “These medications are effective, but they are not a substitute for a healthy lifestyle,” said Shane-McWhorter. “They don’t eliminate the need for a healthy diet and physical activity.”

Because medications alone are not enough for weight loss, encourage patients to leverage all members of the health care team to help them achieve a healthy weight. “They should be working with a dietitian,” said Shane-McWhorter, “possibly an exercise physiologist, or—if it’s a condition such as knee osteoarthritis that keeps them from exercising—a physical therapist.”

Advise women of childbearing age that as they begin to lose weight, they may become more fertile and should use contraception.

Pharmacists should also counsel patients that “for most of these drugs, if you don’t see much of an effect in 12 weeks, there’s no reason to continue taking them,” said Shane-McWhorter.