Weight Loss Drugs

Question 1

Overweight

Answer 1

BMI: 25-29.9 kg/m2

Question 2

Obese

Answer 2

BMI ≥ 30 kg/m2

Question 3

Select drugs that can cause weight gain:

Answer 3

• Antipsychotics (eg, clozapine, olanzapine, risperidone, quetiapine)
• Diabetes drugs (insulin, meglitinides, sulfonylureas, thiazolidinediones)
• Divalproex/valproic acid
• Gabapentin, pregabalin
• Lithium
• Mirtazapine
• Steroids
• TCAs (e.g., amitriptyline, nortriptyline)
• Conditions: hypothyroidism

Others: beta-blockers, dronabinol, hormones (eg, estrogen, megestrol), MAO inhibitors, SSRIs (paroxetine), vasodilators (e.g., minoxidil)

Question 4

Select drugs that can cause weight loss:

Answer 4

• ADHD drugs (e.g., amphetamine, methylphenidate)
• Bupropion
• GLP-1 agonists (e.g. exenatide, liraglutide)
• Pramlintide
• Roflumilast
• SGLT2 inhibitors (e.g. canagliflozin, empagliflozin)
• Topiramate
• Conditions: hyperthyroidism, celiac disease, inflammatory bowel disease

Others: acetylcholinesterase inhibitors (donepezil, rivastigmine, galantamine); antiepileptic drugs (zonisamide, ethosuximide), interferons, thyroid drugs (e.g., levothyroxine)

Conditions: cystic fibrosis, GERD or peptic ulcer disease, lupus, TB

Question 5

Prescription drugs for weight loss can be recommended if the patient:

Answer 5

1. has a BMI ≥ 27 + presence of at least one comorbid condition (HTN, T2D, dyslipidemia)
2. is obese (BMI 30-39.9)

Question 6

Physical activity should be increased to ≥ 150 minutes/week; performed on:

Answer 6

3-5 separate days

Question 7

Weight loss drugs should be discontinued if they do not produce at least a…

Answer 7

5% weight loss at 12 weeks

Question 8

Older stimulant drugs (e.g. phentermine, diethylpropion) are only used…

Answer 8

short-term to “jump-start” a diet

Question 9

The newer drugs can be continued long-term for weight maintenance:

Answer 9

Qsymia, Contrave, Saxenda, orlistat formulations

Question 10

Phentermine/Topiramate ER (Qsymia)
C-IV. REMS drugs due to tetratogenic risk; pregnancy test needed before tx and monthly thereafter; use effective contraception during tx;

Notes: taper off due to seizure risk

Answer 10

Start: 3.75 mg/23 mg PO QAM x 14 days; titrate up based on weight loss
Max dose: 15 mg/92 mg PO QAM
CrCl< 50 mL/min; max dose is 7.5 mg/46 mg/day

C/I: Pregnancy, glaucoma, hyperthyroidism, MAO inhibitor use within past 14 days
S/Es: Tachycardia, CNS effects (eg, insomnia), depression, anxiety, suicidal thoughts, headache, paresthesia, vision problems, constipation, dry mouth, increase SCr, upper respiratory tract infection

Question 11

Naltrexone/Bupropion (Contrave)
Notes: Do not cut, chew, or crush; swallow whole. Do not take with high-fat meal. Discontinue opioids or buprenorphine 7-14 days before using Contrave

Answer 11

ER tablet: 8 mg/90 mg
Week 1: 1 tab PO QAM
Week 2: 1 tab PO QAM, 1 tab PO QPM
Week 3: 2 tabs PO QAM, 1 tab PO QPM
Week 4: 2 tabs PO QAM, 2 tabs PO QPM

C/Is: Pregnancy, chronic opioid use or acute opiate withdrawal, uncontrolled HTN, seizure disorder, use of other bupropion-containing products, bulimia/anorexia, abrupt discontinuation of alcohol, benzos, barbiturates, antiepileptic drugs, use of MAO inhibitors within 14 days. Warnings: Use caution with psychiatric disorders, d/c with s/sx of liver toxicity, can increase HR and BP, glaucoma

Question 12

Liraglutide (Saxenda)

Approved for use in children age ≥ 12 years with weight > 60 kg and BMI corresponding to ≥ 30 kg/m2 for adults

Answer 12

Start 0.6 mg SC daily x 1 week; titrate up by 0.6 mg SC daily at weekly intervals. Target dose: 3 mg SC daily. Titrate to reduce GI effects.

Boxed Warning: risk of thyroid C-cell carcinoma. C/Is: Pregnancy, personal or family history of medullary thyroid carcinoma (MTC) or patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)

Warnings: Pancreatitis, hypoglycemia, acute gallbladder disease, gastroparesis (slows gastric emptying). S/e: nausea, vomiting, diarrhea, constipation, injection site rxns

Question 13

Lipase inhibitor (decrease absorption of dietary fats by ~30%). Must stick to dietary plan for both weight improvement and to help lessen GI side effects (max 30% of kcals from fat)

orlistat; Rx- Xenical; OTC- Alli
Indicated in ages > 12 years
Notes: must be used with a low-fat diet plan. Take multivitamin with A, D, E, K, and beta carotene at bedime or separated by ≥ 3 hours; separate levothyroxine by ≥ 4 hours

Answer 13

Xenical: 120 mg PO w/ each meal containing fat; take with meal or up to 1 hr after eating
Alli: 60 mg PO w/ each meal containing fat
C/Is: Pregnancy, chronic malabsorption syndrome, cholestasis
Warnings: Liver damage (rare), cholelithiasis, increased urinary oxalate/kidney stones, hypoglycemia (in patients with diabetes)
Side effects: GI (flatus with discharge, fatty stool, fecal urgency)

Question 14

Phentermine (Adipex-P, Lomaira)

C-IV

Answer 14

15-37.5 mg PO daily, before or after breakfast, or in divided doses

Question 15

Appetite suppressants

Notes: stimulants taken later in the day can cause insomnia
Potential for misuse/dependence

Answer 15

C/Is: Cardiovascular disease (eg, uncontrolled hypertension, arrhythmias, heart failure, CAD), hyperthyroidism, glaucoma, pregnancy, breast feeding, history of drug abuse, MAO inhibitors within the past 14 days

S/Es: tachycardia, agitation, increased BP, insomnia, dizziness, tremor, psychosis
Monitoring: HR, BP

Question 16

Diethylpropion

C-IV

Answer 16

IR: 25 mg PO TID, 1 hour before meals and mid-evening
SR: 75 mg PO once at mid-morning

Question 17

Phendimetrazine

C-III

Answer 17

IR: 35 mg PO BID-TID, 1 hr before meals
ER: 105 mg PO daily, 30-60 minutes before the morning meal

Question 18

Benzphetamine

C-III

Answer 18

25-50 mg PO daily to TID; avoid late afternoon administration

Question 19

OTC weight loss supplements commonly contain stimulants, such as bitter orange and/or excessive amounts of caffeine, which can be packaged under different names:

Answer 19

• yerba mate
• guarana
• concentrated green tea powder

Question 20

Guidelines recommend weight loss or bariatric surgery for adults with BMI ≥ 40 kg/m2 or when BMI ≥35 kg/m2 with an obesity-related condition. Patients must commit to a lifetime of healthy eating and regular exercise to sustain the weight loss. Some common issues associated with bariatric surgery include:

Answer 20

• Micronutrient deficiencies: calcium, vitamin B12, and iron deficiency, fat-soluble vitamins A, D, E, K.
• Calcium citrate supplementation is preferred as it has non-acid dependent absorption.
• Anemia can result from vitamin B12 and iron deficiency; both may require supplementation.
• Iron and calcium supplements should be taken 2 hours before or 4 hours after antacids.
• Patients may require life-long supplementation of the fat-soluble vitamins A, D, E, and K due to fat absorption.
• Medications may require dose reduction and may need to be crushed and put in liquid or used in transdermal form for up to 2 months post-surgery. Pharmacists need to assess which drugs can be safely crushed and provide alternatives to drugs that cannot be crushed (i.e. ER formulations)
• Rapid weight loss can cause gallstones. Ursodiol (Actigall, Urso 250, Urso Forte) dissolves gallstones and may be needed, unless the gallbladder has been removed.