GIT Lec 8 - Obesity Flashcards
What are the indications of anorexiants (Appetite suppressants?)
They are indicated for short term treatment of obesity since they only work for 5-10 weeks before the body develops tolerance to their anorectic action.
They should be used with caution due to the risk of developing dependence or the risk of abuse.
What is the classification of anorexiant medications?
- Diethylpropion (tenuate) and phentermine (adipex-P or lonamin)
- Dextroamphetamine (Dexedrine) or methamphetamine (desoxyn)
- Sibutramine (meridian)
What is the MOA of diethylpropion?
It works by increasing the release of norepinephrine and dopamine from the nerve terminals. It also inhibits re-uptake of those neurotransmitters thereby increasing the level of neurotransmitters in the brain.
What is the MOA of dextro- and meth- amphetamine?
They work on the epinephrine and dopaminergic pathways
What is the MOA of meridian?
It inhibits re-uptake of serotonin, epinephrine and dopamine which increases the post-ganglionic concentration of those neurotransmitters in the brain that affect food intake.
The dosage is 10-15mg P.O.
What are the side effects of anorexiants?
CNS side effects:
1. Dizziness, headaches
2. Euphoria
3. Fatigue and insomnia
GIT side effects:
1. Dry mouth
2. Nausea
3. Abdominal discomfort and constipation
CVS side effects:
1. Hypertension
2. Palpitations
3. Arrhythmias
- withdrawal of this drug can cause confusion, tremors and headaches. They also should not be given within fourteen days of a monoamine oxidase inhibitor (anti-depressant)
What are the contraindications of anorexiants?
- Pulmonary hypertension
- Peripheral occlusive arterial disease or coronary heart disease
- Cardiac arrhythmias
- Prostatic hypertrophy
- Severe hepatic or renal impairment
What are examples of lipase inhibitors?
- Orlistat (Xenical)
- Rimonabant
- Fenfluramine
- Mazindol
What is the MOA of orlistat?
It is a pentanoic acid ester
1. It binds to and inhibits gastric and pancreatic amylase
2. Consequently; dietary lipids will not be hydrolyzed or absorbed (this will also result in malabsorption of fat-soluble vitamins (DEAK) which are important for health)
3. The resulting inhibition of their activity prevents the absorption of 30% of dietary fat.
4. Although the weight loss occurs due to caloric deficiency, the side effects of the drug also contribute by diminishing food intake
what is the dosing for orlistat?
The typical dose is 120mg taken immediately before or during meals, or 1 hour following main meals; up to 3 times daily.
If a meal is missed or contains no fat, the dose is omitted.
What are the adverse effects of orlistat?
- Flatulence
- Steatorrhea —> fecal urgency
- Increased defecation
- Abdominal and rectal pain.
What are some general advice for patients on orlistat?
- Patients on orlistat should be on a balanced diet and should have their fat intake spread out in relatively balanced or equal proportions over three meals in order to decrease adverse GIT events.
- Patients should be advised to take multivitamins, they should not be taken within 2 hours of the treatment
what are the contraindications of the orlistat?
- Chronic intestinal malabsorption
- Cholestasis
What is the drug that is usually combined with orlistat?
Sibutramine, since they have different MOA’s to reach the same effect.
What are the drug interactions of Orlistat?
It can interfere with the absorption of some drugs like:
1. Amiodarone
2. Levothyroxine, levothyroxine should be separated from orlistat by at least 4 hours.
