Autacoids Flashcards
What are prostaglandins and there function?
Rapidly metabolized to inactive products at site of action
- Produced in every cell in the mammalian body except red blood cells
Misoprostol
Synthetic prostaglandin E1 Pharmacological effects: - Uterine contractions - Cervical ripening - Inhibits gastric acid secretion Therapeutic uses - Induces labor (under FDA review in US) - Abortifacient when combined with mifepristone (Mifepritone) *Synthetic steroid w/ antiprogestional effects * Must be received directly from licensed physician - Prevents NSAID gastric ulcers Benefits: - Low cost - Drug stability - Effective - Less invasive (vs. Oxytocin and vs surgical abortion) Adverse effects: - Fever, Diarrhea, GI disturbances
Alprostadil
Prostaglandin E1
Therapeutic uses:
- Maintains a patent ductus arteriosus in newborns until corrective surgery
- Urethral suppository/injectable for erectile dysfunction
Adverse effects:
- Systemic: less frequent bu can be serios; Flushing, bradycardia, hypotension, tachycardia, cardiac arrest, edema, CHF, hyperemia, 2nd degree heart block
-Localized: Urethral burning, bleeding, urethral/testicular/penile pain
Dinoprostone
Prostaglandin E2
Vaginal insert: must be given by licensed doc
MOA unknown
Therapeutic use:
- Abortion or to induce labor: dilates cervix; induces uterine contractions
Adverse effects:
- Contraindicated in asthmatics
- High fever
- Vomiting/diarrhea (stimulates smooth muscle of GI tract)
Latanoprost/bimatoprost
Prostaglandin F2a analogue - Bimatoprost is producing - Lantanoprost off patent Therapeutic uses: - Opthalmic topical solution in the treatment of open angle glaucoma - Eyelash lengthener in cosmetics - reduces orbital fat Adverse effects: - Heterchromia - Hyperemia - Blurred vision - eyelid redness - Permanently darken eyelashes - Eye discomfort - Thickening of the eyelashes - Herpes simples keratitis - Unexpected facial hair growth
Triptans
Tryptamine based drug MOA: - Act as serotonergic agonists on a subset of seratonin receptors found on small peripheral nerves --- Constriction of nerves which innervate cranial vasculature ---- Reduced inflammatory neuropeptides - May also act directly on blood vessels Therapeutic uses: - Migrane headaches Contraindicated in patients taking SSRIs
Sumatriptan
DMT/5-MeO-DMT analogue Poor oral bioavailability - Commonly given SC - Just approved transdermal patch Adverse effects: - Sulfhemoglobinemia -- seen with large dose - CV-MI, vasospasm, myocardial ischemia - Parasthesia - "pins and needles" - Vertigo
Histamine
Chemical messenger
- Mostly generated in mast cells
- Mediates many cellular responses
(allergic, inflammatory, gastric acid secretion, some neurotransmission)
- No therapeutic uses, but agents that disrupt histamine actions are very useful!
Histamine Location?
Found in almost all tissue, but distributed mainly to places where “inside” meets “outside”
- Lungs, skin, GI tract
Found in some insect stings/venom
Mast cell degranulation
Releases histamine
- Increased local blood flow
- Increased vascular permeability
Can also occur following trauma or chemical damage:
- Allows for macrophages and other immune cells to enter and begin repair process
Anaphylaxis:
- When allergen is distributed systemically, above effects causes severe hypotension, bronchoconstriction, and epiglottal swelling
H1- antihistamines MOA?
Inverse agonists (not antagonists as previously assumed)
- Reduce receptor activity
- More effective at preventing symptoms than reversing them
H1-antihistamines pharmacokinetics?
Well absorbed oral administration
- 1~2 hours for peak plasma concentrations/onset of action
- High bioavailability
- Duration of action ~24 hours
~4-6 hour 1/2 life (meclizine is 12-24 hr)
- 1st generation absorbed into CNS (sedative effect)
H1-antihistamine therapeutic uses?
Allergic/inflammatory response
- Only used when allergic response is mediated by histamine (bronchial asthma is mediated by many other catecholamines besides histamine)
- Most H1-antihistamines are used in OTC allergy medicines
Motion sickness
- Blockade of central H1 and muscarinic receptors helps ease motion sickness (diphenydramine, dimenhydrinate, cyclizine, meclizine, hydroxyzine)
Somnifacients
- Usually off label/self medicating
Adverse effects of antihistamine 1st generation?
Low specificity
Side effects:
- Penetration into CNS (sedation, tinnitus, fatigue, dizziness, blurred vision, incoordination, tremors, hallucinations)
- Dry mouth
- Drug interaction (CNS depressants (ex. ALCOHOL), MAOIs, cholinesterase inhibitors used in AD are less effective
- Overdose
Diphenydramine
Therapeutic uses:
- Counters extrapyramidal effects of antipsychotics (ex. haloperidol)
- IV administration for severe allergic response (instead of epinephrine)
- OTC sleed aid
