The Skinny On Weight Loss Drugs

1. The Skinny On Weight Loss Drugs Siggi Ming, ARNP, NP-C Weight Loss Center of Oklahoma

2. Objectives • Learner will be able to identify pharmacological agents currently approved by the FDA for the treatment of obesity • Learner will be able to identify indications for the use of pharmacological agents when treating overweight/obese patients • Learner will be able to discuss the use of pharmacological agents in combination with behavior modification, nutrition, and use of supplements in the treatment of overweight/obesity

3. Definition of Overweight/Obesity • Overweight: BMI of 25.0 – 29.9 kg/m2 • Obese: BMI of 30.0 – 39.9 kg/m2 • Morbidly Obese: BMI of 40.0 kg/m2 and >

4. When to Treat • Any time comorbidities are present, i.e. DM II, hyperlipidemias, heart disease, GERD, hypertension, metabolic syndrome, sleep apnea, stress incontinence • Any time the patient requests help with weight loss efforts

5. How Is Overweight/Obesity Treated? • Behavior Modification and Lifestyle Changes • Nutritional Counseling • Exercise Counseling • Correcting Endocrine Imbalances • Supplements • Prescription Medications

6. Pharmacologic Agents Orlistat • The only FDA approved drug for long term use • Lipase Inhibitor; inhibits absorption of dietary fat • Minimal systemic absorption • Tmax approx. 8 hrs • Half life approx. 1-2 hrs • Metabolism occurs mainly in GI wall • Elimination via fecal route (97%)

7. Orlistat Indications & Dosage • Obesity Management • Weight Loss • Weight maintenance • 120 mg po tid with or < 1 hr after fat containing meal • Omit if meal is non-fat

8. Orlistat Contraindications • Hypersensitivity • Chronic malabsorption syndromes • Cholestasis • Hx of calcium oxalate kidney stones • Hx of Anorexia or bulimia • Hx of organ transplant

9. Orlistat Adverse Reactions Serious: • Hypersensitivity (anaphylaxis) • Angioedema • Vitamin deficiencies (fat soluble vit) • hepatotoxicity

10. Orlistat Adverse Reactions Common: • Oily spotting • Flatulence with fecal discharge • Fecal urgency and incontinence • Fatty, oily stools • Abdominal discomfort

11. Orlistat Drug Interactions • Warfarin: Watch for increased INR due to decreased Vitamin K absorption • Cyclosporine: Decreased levels • Amiodarone: Decreased levels • Fat soluble vitamins (K, A, D, E): Decreased absorption • Thyroid hormone: Decreased absorption

12. Orlistat Safety • Pregnancy Category B • Lactation safety unknown • Monitoring: no routine testing recommended

13. Drugs approved for short term use • Phentermine • Diethylpropion • Phendimetrazine

14. Phentermine • FDA approved for short term use (up to 12 weeks) • Sympathomimetic; stimulates CNS activity; stimulates catecholamine release, thereby decreasing hunger • Rapidly absorbed from GI tract • Half life approx. 24 hrs • Excretion: 70-80% unchanged in urine

15. Phentermine Indications & Dosage • Short term treatment of obesity • 37.5 mg po qd before 1000 to avoid insomnia • Start with ½ strength • Increase dosage to full strength if ½ strength not causing enough appetite suppression

16. Phentermine Contraindications • Hypersensitivity • MAOI use • Arteriosclerosis • Cardiovascular disease • Hyperthyroidism • Glaucoma • Agitation • Hx of drug abuse • Pregnancy • Breastfeeding

17. Phentermine Adverse Reactions Serious: • Dependency • Psychosis • Tachycardia • Hypertension • Pulmonary hypertension • Valvular heart disease

18. Phentermine Adverse Reactions Common: • Palpitations • Tachycardia • Restlessness • Insomnia • Diarrhea • Xerostomia • Hypertension • Euphoria • Headache

19. Phentermine Drug Interactions • Anorexiants/stimulants (increased risk of CV, CNS stimulation) • MAOIs (hypertensive crisis) • Linezolid (increased risk for HTN) • Effexor (additive effect)

20. Phentermine Safety • Pregnancy Category C • Lactation: possibly unsafe • CV evaluation at baseline (ECG, BP, physical CV exam; consider echo at baseline and after dc) • Schedule IV

21. Diethylpropion • FDA approved for short term use (up to 12 weeks) • Sympathomimetic; stimulates CNS activity; stimulates catecholamine release, thereby decreasing hunger • Rapidly absorbed • Half life 4-6 hrs • Excretion: urine

22. Diethylpropion Indications & Dosage • Short term treatment of obesity • 25 mg po up to tid; 75 mg ER qd • 25 mg approx. 1 hr before “hungriest” time of day; may take up to tid • Do not take after 1600 to avoid insomnia • 75 mg ER q am

23. Diethylpropion Contraindications • Hypersensitivity • Pulmonary hypertension • Severe hypertension • Agitation • Valvular heart disease • Heart murmur • Cardiovascular disease • Seizure disorder • Advanced arteriosclerosis

24. Diethylpropion Adverse Reactions Serious: • Tachycardia • Hypertension • Pulmonary hypertension • Valvular heart disease • Hallucinations • Psychosis • Leukopenia

25. Diethylpropion Adverse Reactions Common: • Dry mouth • Diarrhea/constipation • Restlessness • Anxiety • Insomnia • Headache • Hypertension • Palpitations • Arrhythmias

26. Diethylpropion Drug Interactions • Anorexiants/stimulants (increased risk of CV and CNS stimulation • MAOIs (hypertensive crisis) • Linezolid (increased risk of HTN) • Effexor (additive effects)

27. Diethylpropion Safety • Pregnancy Category B • Lactation safety unknown • Cardiovascular evaluation at baseline; ECG, BP, physical CV exam) • Consider echo periodically and after dc • Schedule IV

28. Phendimetrazine • FDA approved for short term use (up to 12 weeks) • Sympathomimetic; stimulates CNS activity; stimulates catecholamine release, thereby decreasing hunger • Rapidly absorbed • Half life 2 hrs (10 hrs ER) • Excretion: urine

29. Phendimetrazine Indications & Dosage • Short term treatment of obesity • 17.5-35 mg po bid-tid; 1 hr ac • Do not give after 1600 to avoid insomnia • 105 mg ER po q am 30-60 mins ac

30. Phendimetrazine Contraindications • Hypersensitivity • Symptomatic cardiovascular disease • Moderate/severe hypertension • Hyperthyroidism • Agitation • MAOI use • Valvular heart disease • Pregnancy • Glaucoma • Advanced arteriosclerosis

31. Phendimetrazine Adverse Reactions Serious: • Hypertension • Tachycardia • Pulmonary hypertension • Withdrawal if abrupt dc after long term high-dose use

32. Phendimetrazine Adverse Reactions Common: • Palpitations • Tachycardia • Restlessness • Hypertension • Insomnia • Agitation • Dizziness • Headache • Flushing • Sweating • Tolerance • Diarrhea/constipation

33. Phendimetrazine Drug Interactions • Anorexiants/stimulants (increased risk of CV and CNS stimulation • MAOIs (hypertensive crisis) • Linezolid (increased risk of HTN) • Effexor (additive effects)

34. Phendimetrazine Safety • Pregnancy Category C • Lactation possibly unsafe • Cardiovascular evaluation at baseline; ECG, BP, physical CV exam • Consider echo periodically and after dc • Schedule III

35. Drugs Used Off Label Pristiq • Antidepressant (SNRI) • Side effects include decreased appetite, weight loss • Seems to decrease cravings

36. Drugs Used Off Label Topamax • For migraine/headache; seizure disorders • Side effects include weight loss, anorexia • Many undesirable side effects

37. Drugs Used Off Label Spironolactone • Decreases CHO cravings • Useful prior to menses • Start the day premenstrual S/S begin, stop when menstrual flow ceases

38. Drugs Used Off Label Pindolol • Weak beta blocker • Use with phentermine, diethylpropion to block stimulant effect without affecting anorectic effect

39. hCG • Human chorionic gonadotropin • Hormone secreted by the female body in response to pregnancy • Used off and on since the 1950s in conjunction with a very low calorie diet (usually 500 kcal/day)

40. hCG • No evidence that hCG is associated with weight loss • No evidence that the use of hCG is safe • ASBP strongly discourages the use of hCG for weight loss

41. Supplements Good quality supplements can aid weight loss efforts by - raising resting metabolic rate - increasing lipid metabolism - curbing hunger - raising energy levels

42. Combined Effort • Nutrition • Behavior • Lifestyle • Medications/Supplements