Pharm General Flashcards
Drugs involved with first pass metabolism
Nitrates have Large Pre-Systemic Metabolism Vary Its Administration Type
- Nitrates (isosorbide dinitrate glyceryl trinitrate)
- Hydrocortisone
- Lignocaine
- Propranolol
- Salbutamol
- Morphine
- Verapamil
- Isoprenaline
- Aspirin
- testosterone
What is pharmacokinetics & phases
what the body does to the med
absorption
distribution
metabolism
Distribution
What is First past metabolism & mnemonic?
Concentration of a drug is greatly reduced before it reaches the systemic circulation thus doses or give other routes.
Solution = different administration
Nitrates have Large Pre-Systemic Metabolism Vary Its Administration Type
What is Zero-order kinetics & mnemonic
a constant amount of drug is eliminated per unit time.
Pea WHEATT
Drugs that have zero order Kinetics/ elimination
Pea WHEATT
Phenytoin
Warfarin
Heparin
Ethanol
Aspirin (high dose )
Theophylline
Tolbutamide
How does liver failure and Kidney failure lead to reduced volume of distribution
Drug bound to plasma are filtered out before getting to the circulation
First -order kinetics/ emlination
kinetics occur when a constant proportion of the drug is eliminated per unit time.
Define phase I reactions:
oxidation, reduction, hydrolysis
are typically more active and potentially toxic
Cytochome P450
Define phase II reactions:
conjugation
typically inactive and excreted in urine or bile
Acetylator status: Deficient in Hepatic N-acetyltransferase
Drugs affected by acetylator status (Deficient SHIP)
* dapsone
- sulfasalazine
- hydralazine
- isoniazid
- procainamide
Define competitive antagonist
medication that reversibly binds to the same receptor site where an agonist binds, but it does not activate it. decrease the agonist potency, but do not affect the agonist efficacy
It just blocks site
Define Non-competitive antagonist-
Where do they bind
What happens after binding
What type of binding
- bind to “allosteric site” or agonist binding site
When they bind, the shape of the receptor changes so the ligand can no longer recognize & can’t produce the agonist effect.
Binding is irreversible or it dissociates very slowly.
Alpha-1 adrenergic receptors fx and location
Blood vessel
Eye
Bladder
are mainly located on the walls of blood vessels, and when stimulated, they cause vasoconstriction, thus decreasing blood flow to tissues.
2. In the eyes
trigger mydriasis, or pupil dilation.
- bladder, -sphincter constriction and urinary retention, or holding the urine within the bladder.
And in males, they trigger ejaculation.
Alpha-2 adrenergic
Fx
Location
Example
receptors are primarily found on the presynaptic neuron inhibits further release of norepinephrine and serves as a mechanism of negative feedback control.
Mirtazapine
Alpha-1 adrenergic Blker
Non-Selective drug
Examples
non-selective blockers, Phenoxybenzamine, -irreversible antagonist, Rx for pheochromocytoma;
Phentolamine, a reversible antagonist, mainly used to treat hypertensive crisis caused by the combination of MAOIs, and tyramine-rich foods.
Alpha-1 adrenergic Blker
Selective drug Examples/ uses
Hypertension treatment: prazosin, terazosin, and doxasozin,
Tamsulosin, which relieves the symptoms of benign prostatic hyperplasia.
Side effects of Alpha adrenergic inhibition
-blocks the action of adrenaline on the alpha receptors.
1. tachycardia and arrhythmia
2. nasal congestion
3. sexual dysfunction
Where are Beta1 receptors found (2)
- Heart- increase HR & contractility
- Kidney stim juxtaglomerular cells,=release renin = increase BP
Where are Beta2 adrenergic receptors (5)?
-
Smooth muscle cells in the walls of blood vessels of skeletal mscls & brain, = vasodilation & increased blood flow to these tissues.
bronchodilation, and that increases oxygen delivery to cells. - GI tract, = decrease motility & slow digestion.
- Eyes, = promote the secretion of aqueous humor,
- Liver, = release glucose into blood & the release of glucagon=raise blood glucose levels.
- Breaks down triglycerides into free fatty acids and cholesterol.
First generation non- selective beta blockers,
Examples
- antagonists on both beta1 and beta2 adrenergic receptors.
1. propranolol,
timolol,
nadolol,
sotalol
pindolol.
SE. & Contraindications non- selective beta blockers,
What happens with Sudden stoppage
- Bradycardia
- Hypotension
- Sudden stoppage = severe rebound tachycardia, Htn , or even arrhythmias,
- Propanol effects CNS = dizziness, depression, insomnia,
- Wheezing- not used in COPD or asthma
- Diarrhea
- Hypertriglyceridemia,
- Hypoglycemia,
2nd generation of beta blockers are selective for
effects
Examples
Beta1 adrenergic receptors
Lower BP (decreasing HR & contractility),
kidneys decrease renin release = lower BP
metoprolol and bisoprolol safe in obstructive d’s & DM
3d generation of beta blockers
Effects (2)
Examples (2)
blocking beta1 receptors, these medications also block alpha1 receptors in the blood vessels,
labetalol and carvedilol
Direct cholinomimetics
- Receptors acted
- reaction Acetylcholinesterases
-Examples
mimic the action of acetylcholine by directly acting at muscarinic or nicotinic receptors.
- NOT degradation by Acetylcholinesterases. and have a long lasting or more potent effect.
bethanechol, carbachol, methacholine, and pilocarpine
