Block 3 Drugs Flashcards
Atropine
Muscarinic antagonist
Uses:
- preanesthetic to prevent respiratory secretions
- to treat sinus bradycardia
- blockade of excessive muscarinic receptor activation
Sites of action:
- heart - high dose can cause tachy
- lungs - causes bronchodilation, decreased secretion
- GI - decreased motility
- glands - decreased salivation and sweating
Busiprone
5-HT1A partial agonist
Use:
- treating dyspepsia (upset stomach/indigestion)
- an anxiolytic for anxiety disorders
Mechanisms:
- induces relaxation of proximal stomach
Cimetidine
Histamine H2 receptor antagonist
Use:
- for duodenal/gastric ulcers
- hypersecretion of acid
- GERD
Mechanisms:
- inhibits acid secretion into stomach
Notes:
- inhibitor of many isozymes of the cytochrome P450 enzyme system (CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4)
Erythromycin
Macrolide antibiotic; motilin receptor agonist
Use:
- treating resp. tract + soft tissue infections
- treating gastroparesis (delayed gastric emptying) due to its pro-motility effect
Mechanisms:
- binds to 50s ribosomal subunit thus inhibiting bacterial protein synthesis
- as a motilin receptor agonist by direct muscular and indirect NT effects to stimulate GI motility
Fluoxetine
SSRI antidepressant
Used to treat:
- depression
- obsessive compulsive disorder
- bulimia nervosa
Mechanism:
- selective serotonin reuptake inhibitor (SSRI) at all SERT sites, in both CNS and PNS
Metoclopramide
5-HT3 antagonist; 5-HT4 agonist; dopamine D2 receptor antagonist; prokinetic drug
Use:
- treating reflux esophagitis
- for pre-op gastric emptying
- reduces chemotherapy-induced nausea
- an antiemetic
- is prokinetic (enhances GI motility)
Mechanisms:
- 5-HT3 antagonist
- 5-HT4 agonist
- Metoclopramide is a dopamine D2 receptor antagonist in CNS + PNS
- Dopamine D2 receptors inhibit ACh release (ACh is needed for gut motility)
- indirectly increases ACh release in gut
Misoprostol
Synthetic oral prostaglandin E1 analog
Use:
- for preventing gastric and duodenal ulcers secondary to use of NSAIDS, but currently indicated only for prevention of gastric ulcers
Mechanism:
- exerts a mucosal protectant effect. Its cytoprotective effect is secondary to: mucus and bicarb secretion, prevention of mucus bilayer disruption, reduction of backflow of H+, regulation of mucosal blood flow
Neostigmine
Carbamate-type peripheral cholinesterase inhibitor
Use:
- for myasthenia gravis dx and treatment
- paralytic ileus (neostigmine increases gastric motility)
- lack of bladder tone
- reversal of neuromuscular blockade following anesthesia
Notes:
- carbamate-type acetylcholinesterase inhibitor in periphery
Octreotide
Synthetic analog of somatostatin
Use:
- treating diarrhea, other abdominal illness
- for intestinal tumors, vasoactive intestinal peptide tumors, metastatic carcinoid tumors, acromegaly (excess growth hormone), variceal bleeding, orthostatic hypotension
Mechanisms:
- antidiarrheal - mimics somatostatin pharmacologically
- inhibits gastric acid and pepsin secretion
- reduces GI motility
- Inhibits contraction of gallbladder and bile flow
- reduces liver blood flow
Omeprazole
Proton pump inhibitor (PPI)
Used to treat:
- gastroesophageal reflux disease
- duodenal ulcer
- hypersecretory states (Zollinger-Ellison syndrome)
Mechanism:
- blocks acid secretion by irreversibly inhibiting the H+/K+ ATPase in parietal cells
Ondansetron
5-HT3 antagonist
Use:
- a prophylactic used to treat nausea and vomiting following chemotherapy
- for postoperative vomiting
Mechanism:
- 5-HT3 serotonin receptor antagonist
- its effects are BOTH in periphery and at chemotrigger zone (CTZ, an area of brain that receives input from blood-borne drugs or hormones)
Notes:
- granisetron is in the same class
Ranitidine
Histamine H2 receptor antagonist
Used to treat:
- duodenal/gastric ulcer
- hypersecretion of acid
- GERD (gastroesophageal reflux disease)
Mechanism:
- inhibits secretion of acid in stomach
- more potent than cimetidine
Notes:
- fewer side effects of cimetidine
Sulcralfate
Cytoprotectant; mucosal coating agent
Used to treat:
- gastric, duodenal, and stress ulcers
Mechanisms:
- acts locally (not systemically) to complex with proteins at ulcer site
- forms protective, viscous, adhesive barrier on surface of intact mucosa of stomach and duodenum
- inhibits pepsin activity
Sumatriptan
5-HT1B/1D receptor and 5-HT1P receptor agonist
Used to treat:
- functional dyspepsia with impaired accommodation
- acute migraine
- cluster headache attacks
Mechanism:
- Its peripheral actions include fundal relaxation and reductions in antral motility
- as a 5-HT1B/1D receptor agonist it causes vasoconstriction
Insulin
Always give insulin to diabetics REGARDLESS OF GLUCOSE LEVELS b/c lack of it can result in life-threatening ketoacidosis.
If glucose is low, give insulin + glucose to avoid ketoacidosis.
Insulin acts on receptors which, through a cascade, lead to increased amounts of GLUT 4 (glucose transporters) on the cell membrane.
Causes weight gain.
Metformin
First choice drug to treat Type 2 DM
It makes the liver more sensitive to insulin (“hearing aid for the liver”).
Inhibits gluconeogenesis.
Enhances GLUT 4 translocation (GLUT 4 then brings in glucose from blood into cells)
Makes people eat less.
Decreases risk of cancer.
Sulfonylureas (glucotrol, glipizide)
Treating Type 2 DM
Stimulates beta cells of the pancreas to secrete more insulin
Dr. Butler does not like this drug
Thiazolidines (pioglitizone)
Treating Type 2 DM.
Enhances insulin receptor activity
Enhances GLUT4 translocation in fat cells.
HOWEVER, risk for MI and stroke are the same
Glitazones
Treating Type 2 DM.
Enhances how insulin works at the muscle, but has side-effects
Glucagon like peptide (GLP-1)
Incretin mimetics (exenatide)
For treating diabetes.
Incretin, a naturally occuring hormone secreted by intestines in response to food intake, acts on pancreas to stimulate secretion of glucose-dependent insulin.
DOES NOT CAUSE weight gain. Is associated with weight loss. This is a good thing for Type 2 DM.
Dipeptidyl peptidase-4 (DPP-4) inhibitors (sitagliptin)
For treating diabetes.
DPP-4 degrades incretin.
Increases incretin available to respond to elevated glucose levels by limiting rapid degradation of incretins by DPP-4 enzyme.
DOES NOT cause weight gain.
Oxybutynin (Ditropan)
Anticholinergic, antimuscarinic (non-selective)
Use:
- Is a bladder muscle relaxant, it suppresses urge to void
Mechanisms of Action:
- inhibits involuntary detrusor muscle contractions caused by detrusor muscle instability (non-neurogenic) or detruso muscle hyperreflexia. Reduced contractions allow the bladder to relax and increase its visceral capacity
Notes:
- There are cholinergic muscarinic m2 and m3 receptors on the detrusor muscle of the urinary bladder wall
Tolderodine (Detrol)
Anticholinergic, antimuscarinic
Use:
- a bladder muscle relaxant (same class as oxybutynin)
Mechanism of Action:
- Same as oxybutynin
Note:
- There are cholinergic muscarinic m2 and m3 receptors on the detrusor muscle of the urinary bladder wall
Amitriptyline (Elavil)
Tricyclic Antidepressant
Use:
- has multiple applications - e.g. as a bladder relaxant
Mechanism:
- acts as a reuptake blocker at NE and 5-HT nerve terminal resulting in increases of NE and 5-HT extraneuronal concentrations.
- Decreases bladder contractility due to its antimuscarinic effects.
Note:
- bladder has cholinergic m2 and m3 receptors.
5-alpha-reductase inhibitors (same class as finasteride (Proscar), dutasteride (Avodart))
5-alpha-reductase inhibitor
Use:
- treating symptomatic benign prostatic hypertrophy (BPH)
Mechanism:
- Reduction in prostate hyperplasia; a competitive specific inhibitor of type II 5-alpha-reductase, an intracellular enzyme that converts testosterone to dihydrotestosterone. In BPH, dihydrotestosterone acts as a potent cellular androgen and promotes prostate growth. Thus, inhibiting the reductase enzyme lowers dihydrotestosterone levels which reduces excessive prostate growth.
Vasodilators
Same class as: sildenafil (Viagra, Revatio), vardenafil (Levitra), tadalafil (Cialis)
Vasodilator
Use:
- treating male erectile dysfunction (impotence) and pulmonary arterial HTN
Mechanism:
- inhibitor of cGMP specific phosphodiesterase type 5 (PDE 5).
- PDE 5 inhibitors inhibit degradation of cGMP in the corpus cavernosum, thereby prolonging cGMP action (see below)
Note:
- Part of the process of erection involves the parasympathetic nervous system causing the relase of nitric oxide (NO) in the corpus cavernosum of the penis. NO binds to the enzyme guanylate cyclase which results in increased levels of cGMP. This leads to smooth muscle relaxation (vasodilation) in the corpus cavernosum resulting in increased inflow of blood and an erection. Breakdown of cGMP by PDE 5 limits the degree of vasodilatation and limits erection of the penis.
Alpha-Adrenergic Antagonists
Same class: terazosin, doxazosin, tamsulosin (Flomax), alfuzosin (Uroxatral)
Selective alpha-1 receptor antagonist
Use:
- for treatment of benign prostatic hyperplasia (BPH)
- Alfuzosin, doxazosin, tamsulosin, terazosin are all comparable in the treatment of BPH.
Mechanism:
- relaxes the smooth muscle of the prostate and bladder neck to facilitate bladder emptying.
Essure
Nonsurgical female sterilization
Hysteroscopic placement of metallic microcoils in both proximal fallopian tubes. Fibrotic response occludes the tubes in 3 (96%)-6 months (100%).
Adiana
Nonsurgical female sterilization
Hysteroscopic placement of polymer matrix in both proximal fallopian tubes. Uses radiofrequency energy to stimulate vascular tissue growth into the polymer matrix.
Effectiveness: 98.9%
Copper T
Progestin IUD (Progestasert, Mirena)
Intrauterine Device
Copper T - hormonally inert (?) and lasts for 10 years
Progestasert (1 year) and Mirena (5 years) release a synthetic progesterone called levonorgestrel
Depo-Provera, DMPA-104
Injectable IM or SQ
Progestin, 4 shots per year.
Targets pituitary LH and FSH.
Implanon
Progestin Implant (SQ)
Lasts for 3 years. Targets pituitary LH and FSH
OrthoEvra
Transdermal patch
Estrogen + progesterone, weekly.
Targets pituitary LH and FSH.
Nuvaring
Vaginal ring
Estrogen + progesterone, monthly.
Targets pituitary LH and FSH.
Preven
Emergency Contraceptive
Two doses of estrogen + progestin 12 hours apart.
Plan B (and Plan B one-step)
Progestin-only emergency contraceptive that prevents LH surge and subsequent ovulation if taken prior to these events.
Plan B is two doese of progestin 12 hours apart
Plan B one-step is one high dose of progestin
RU-486 (aka Mifepristone)
Emergency contraceptive
Progesterone receptor antagonist
One dose, not in clinical use
100% effective
EllaOne
Emergency Contraceptive - selective progesterone receptor modulator (SPRM)
Delays ovulation via LH inhibition.
Single 30 mg dose effective up to 5 days/120 hours after intercourse
