Week 2 Flashcards
drug therapy in pediatrics
- highly sensitive due to immature organs
- adjust dosage based on WEIGHT or BSA (body surface area)
- PO route preferred
FDA pregnancy categories - A
- no evidence of risk
- in controlled human study
- e.g. thyroid H, folic acid, prenatal vitamins
FDA pregnancy categories - B,C D
some risks
FDA pregnancy categories - X
- human teratogen
- contraindicated
- e.g. warfarin, live vaccines, accutane
drug therapy during breast feeding
- can be excreted in breast milk
- little research done
- take drug w/ shorter half life
- take after breastfeeding
- worst case - switch to formula
drug therapy in geriatric patients
- physiologic age more impt than chronological age= individualize therapy (decreased physiologic function –> increased toxicity)
- likely to have multiple disorders – polypharmacy –> drug interactions/toxicity
- should include simple dosing regimens
- frequent plasma drug levels
Acetylcholine
- neurotransmitter of the PNS
- released by somatic NS & parasympathetic NS
- released by all preganglionic neurons
- degraded by acetylcholinesterase (AchE)
Norepinephrine
- released by sympathetic NS
- REuptake into nerve terminals – > stored in vesicles for reuse OR destroyed by MAO (monoamine oxidate)
epinephrine
- release by adrenal medulla
- into blood stream –> hepatic metabolism
receptors of PNS - cholinergic
- nicotinic - skeletal muscles (somatic)
- muscarinic - internal/target organs of parasympathetic NS (rest, relax, eliminate)
receptors of PNS - adrenergic
sympathetic NS
- alpha 1 - peripheral blood vessels = vasoconstriction/incr BP
- alpha 2 - CNS =
- beta 1 - heart
- beta 2 - lungs, liver, uterus
- dopamine
activation of muscarinic cholinergic receptors
elicits parasympathetic response in target organ
activation of nicotinic cholinergic receptors
causes contraction of skeletal muscle
effects of drugs on steps of synaptic transmission
- alter synaptic transmission
- receptor selectivity - nonselective have more side effects
- influence receptor activity on target cells - agonists or antagonists
drugs that affect cholinergic receptors
- muscarinic agonists (cholinergics)
- muscarinic antagonists (anticholinergics)
- cholinesterase inhibitors
- neuromuscular blockade
muscarinic agonists (cholinergics)
- parasympathomimetic agents = mimic parasympathetic
- stimulate activity of target cells
- mimic action of Ach
Ex. Bethanechol (urecholine)
1. constrict iris sphincter (mitosis)
2. ↓ HR
3. bronchoconstriction; ⇡secretion
4. ⇡saliva, GI secretion, ⇡ motility, defecation
5. ⇡ sweating
Bethanechol (urecholine)
- cholinergics
MOA - activates muscarinic cholinergic receptors
No effect on nicotinic cholinergic receptors
Indicated for: urinary retention in post-op or part
SEs - ↓ HR, bronchoconstriction, cramping/diahrrea
Contraindicated for asthma pt
NI: ck HR, measure output
muscarinic antagonists (anticholinergics)
- parasympatholytic drugs = inhibit parasympathetic system (act like sympathetic)
- bind to muscarinic cholinergic receptors & inhibit activity of target cells.
- block the action of Ach at receptors
Effect:
eyes: mydriasis (dilate)
⇡ HR
bronchodilation
↓ saliva, ↓ motility
↓ emptying (promotes urine retention)
↓sweating
Atropine
anticholinergic
Side effects: eyes: photophobia, blurred vision, ⇡ IOP ⇡ HR bronchodilation dry mouth, constipation urinary retention no sweating, so at risk for hyperthermia / hot / red skin
Nursing implications & pt ed: anticholinergics
- drink water
- sunglasses
- intake of fiber (for constipation)
- show how to check pulse (for tachycardia)
cholinesterase inhibitors
- degrade cholinesterase, so more ACh is allowed
1. reversible
2 irreversible
myasthenia gravis
autoimmune disease that destroys ACh receptors
- s/sx muscle weakness & fatigue; eyelid droops; diplopia;
myasthenia crisis: sudden exacerbation of s/sx = respiratory weakness, needs ventilator
diagnose w/ anti cholinesterase test - short term, quick acting - if symptoms subside = make diagnosis = therapy is Neostigmine
reversible cholinesterase inhibitors
MOA - prevent degradation of ACh by AChE
⇡ ACh transmission at all cholinergic receptors
SE: cholinergic OD (crisis) - excessive stem of all cholinergic receptors
- ↓ HR
- muscle weakness – respiratory failure
Ex. Neostigmine
Antidote: ATROPINE, intubation & mechanical ventilation
irreversible cholinesterase inhibitors
- long duration & toxic effects
- puts pt into cholinergic crisis (excessive muscle & CNS stimulation)
- caused by insecticides, nerve gas, chemical weapons
- antidote: ATROPINE
neuromuscular blockade
“nicotinic cholinergic blockage” - block nicotinic cholinergic receptors @ NMJ
- prevent ACh from activating receptors on skeletal muscles –> muscle weakness (flaccidity/paralysis
Indications: used in ICU & surgery, intubation
- no effect on pain or consciousness (!); must be used with anesthetic & analgesic
botulinum toxin (botox)
neurotoxin - blocks release of ACh & block neurotransmission at NMJ
Indications:
cosmetic; severe underarm sweating, migraine HA, overactive bladder, limb spasticity (parkinson’s)
SE: HA, loss of facial expression, flu-like symptoms
Contraindications: preg, breast-feeding
Adrenergic receptors
sympathomimetics - mimics actions of sympathetic NS
Main effects are on: heart, lungs, blood vessels
where are: Alpha-1
eyes, blood vessels
where are: Alpha-2
CNS
where are: Beta-1
heart
where are: Beta-2
lungs
Cathecholamines
adrenergic agonist
- IV only
- brief duration of action
- used for cardiac stimulants
- don’t cross BBB
Epinephrin (Adrenalin)
drug of choice in cardiac arrest, anaphylactic shock
- ⇡blood flow to vital organs - heart, lung, brain
- ↓ blood flow to periphery - skin, kidney
Route: injection (EpiPen), inhalation
IV, topical w/lidocaine
adrenergic antagonists
blockers / sympatholytics
Actions: ↓HR, vasodilation, ↓ BP, ⇡bronchconstriction
mitosis
Drugs for glaucoma
caused by ⇡IOP; can be open angle (90%) or closed angle (10%).
SE - blurred vision, systemic absorption = bradycardia, bronchospasm
Rx:
1. PARASYMPATHOMIMETICS (Piolcarpine.Humorosol) or 2. PROSTAGLANDIN ANALOGS (Latanoprost or Travoprost)
3. BETA BLOCKERS (-olol)
4. CARBONIC ANHYDRASE INHIBITORS (Acetazolamide (Diamox) PO or Trusopt (eye drops))
DO NOT GIVE ATROPINE
parasympathomimetics - to treat glaucoma
pupil constriction - ⇡ outflow of aqueous humor
Ex: Pilocarpine; Humorosol
SE: ↓ night vision
open angle glaucoma
progressive loss of peripheral visual field (tunnel vision)
90% of cases
Rx: eye drops, systemic drugs (Timolol)
Goal: reduce IOP in anterior chamber (promote drainage)
Contraindicated: asthma pt, CAD (coronary artery disease)
closed angle glaucoma
- less common, but is an emergency when occurs (acute onset)
- w/o treatment – blindness w/in 1-2 days
- very painful
factors affecting hemodynamics (BP)
- Heart
- Blood volume
- Arterioles
RAAS
Renin Angiotensin Aldosterone System
