Drugs Flashcards
Chloramphenicol
In neonates interferes with mitochondrial ribosomes and causes gray baby syndrome. Sx- poor feeding, decreased breathing, CV collapse, cyanosis, and death
Succinylcholine
short acting muscle relaxer used in surgery. Butyrylcholinesterase (BChE) hydrolysis of this creates a decreased rate of metabolism of succinylcholine resulting in prolonged paralysis after drug exposure.
N-acetyltransferase 2 (NAT2)
Catalyzes the acetylation (route of metabolism for specific drugs) of isoniazid, hydralazine, and procainamide. This does either slow or fast acetylators (slow=build up and fast = not working)
CYP2D6
Metabolizes metoprolol (lowers <3 rate), haloperidol (Antipsychotic), codeine, and fluoxetine (Depression)
Metoprolol
A beta blcoker used to decrease the heart rate. A poor metabolizer has potential toxicity with standard doses of this medication.
Codeine
Ineffective w/out metabolism by CYP2D6 to from the more potent opioid morphine. Normal codeine does not result in overdose.
Thiopurine S-Methyltransferase (TPMT)
Catalyzes the S-mehtylation of thiopurine drugs such as 6-mercaptopurine and azathiprine immunosuppressant agents (Used in CHEMO)
Zileuton
used for asthma by decreasing the airway inflammation by inhibitiing 5-lipoxygenase.
Warfarin
Metabolized predominately by CYP2C9. Warfarin’s target is viamin K epoxide reductase (an enzyme that is required for vitamin K dependant generation of clotting factors)
Abacavir
HIV medication that has an idiosyncratic reaction with HLA-B*5701 by inducing hypersensitivity.
Aminoglycoside Antibiotics
Gentamicin, tobromycin, amikacin, neomycin, and streptomycin. Must be administered via a parenteral route due to poor GI absorption. Very water soluble w/ poor distribution into adipose tissue. Clearance is almost entirely renal
Vancomycin
Antibiotic.
Poorly absorbed orally although useful in tx of C.diff with PO route. Systemic infections require parenteral dosing.
Increases levels/effects of aminglycosides- used for infections together.
Half life of 5-11 hrs.
Phenytoin
Absorption from oral route is slow.
Highly protein bound
Consider diseases that result in decreased serum albumin concentration such at burns, nephrotic syndrome, and renal failure.
An example of a P450 inducer
Moves from 1st order quickly to zero order occurring even at therapeutic levels
Valproic acid
Used as antiepileptic and as a mood stablizer.
Bioavailability 90% relative to IV dose
Saturable protein binding 80-90% free fraction.
Metabolism extensively hepatic via glucuronidation (conjugation)
Only p450 inhibitor (in antiepileptic class.
Relationship b/w dose and total valproate [ ] is not linear.
Draw levels 2-4 days of initiation to etermine total valproic acid.
Carbamazepine
Anti-epileptic
Slow absorption
Highly protein bound to plasma albumin and alpha1-acid glycoprotein.
Concamitant tx w/ valproate sodium results in higher free fraction
Eliminated primarily by metabolic route, one active metabolite, carbamazepine 10, 11 epoxide.
Metabolized primarily by CYP3A4
Induces own metabolism and goes from a long 1/2 life to a shorter one.
Steady state= 2-5 days
Warfarin
Oral anticoagulant-rapid complete absoption. Onset of action 24-72 hrs. Peak effect 5-7 days Highly protein bound (99%) Metabolism primarily by CYP2C9
Digoxin
Cardiac medication
Absorbed by passive non-saturable diffusion in SI.
Distribution phase lasts 6-8 hrs.
Large volume to distribution. After distribuiton you have a 70:1 in the heart vs. in the blood.
Very narrow therapeutic index
Epinephrine
Andrenergic Agonist
Interacts with both alpha and beta
Low dose- mainly beta effects (vasodilation); high dose- alpha effects (vasoconstriction
CV: + inotropic, + chronotropic- increased CO
Alpha effects- vasoconstricts arterioles
B2- vasodilates vessels to liver and skeletal muscle
Net result- increased SBP w/ slight decrease in DBP
Respiratory- bronchodilation of smooth muscle (B2)
Hyperglycemia-decreased insulin release (alpha2) increased glycogenesis, increased release of glucagon (B2)
Lypolysis B1
Epinephrine therapeutic uses
Emergent tx of asthma, glaucoma, anaphylaxis, w/local anesthetics to prolong DOA through vasoconstriction
Epinephrine ADRs
CNS- anxiety, fear, tension, HA, tremor, hemorrahage, increased BP, cerebral hemorrhage
CV-arrhythmias
Pulmonary edema
Norepinephrine
Adrenergic Agonist
At therapeutic doses alpha 1 and beta 1 receptors are afected
CV- vasoconstriction in periphery (including kidney) reulting in elevated BP, baroreceptor reflex: increase BP -> increased vagal activity stimulation baroreceptors causing bradycardia.
Tx use shock through vascular resistance, increase BP
Dopamine
Adrenergic Agonist
Low doses act predominately on D1 receptors in renal, mesenteric, and coronary vascular beds (vasodilation).
Higher doses a positive inotrope (action at beta1)
High doses- vasoconstriction via alpha 1 receptors
DOC for shock, at appropriate doses is useful in management of low CO associated with compromised renal function such as in severe CHF.
Methoxamine
Adrenergic Agonist
Alpha 1 selective agonist
Not used often but used to tx shock
Phenylephrine
Adrenergic Agonist
Alpha 1 selective agonist
Used like psuedofedrin, Topical constrict vascular smooth muscle in relief or nasal congestion
Not catechol derivative so substrate for COMT
Induces reflex bradycardia when given parenterally, raises BP due to vasoconstriction.
Oxymetazoline
Adrenergic Agonist
Alpha 1 selective agonist
Topical, constrict vascular smooth muscle in relief of opthamic hyperemia.
Chlonidine
Adrenergic Agonist
Alpha 2 selective agonist
Lowers BP by suppressing sympathetic outflow
ADR dry mouth and sedation
a-methyldopa
Adrenergic Agonist
alpha 2 selective agonist
Metabolized to a-methylnorepinephrine which is an a agonist in CNS to decrease sympathetic outflow
Gaunfacine
Adrenergic Agonist
a-2 agonist in CNS to decrease sympathetic outflow
ADR dry mouth and sedation
Isoproterernol
Adrenergic Agonist
Nonspecific B agonist (acts at B1 and B2)
CV: + inotropic and chronotropic effects (B1); vasodilation of arterioles of skeletal muscle (B2)
Pulmonary- bronchodilation (B2)
Uses- stimulates heart in emergencies
Dobutamine
Adrenergic Agonist
B1 selective
Increases cardiac rate and output, usted to increased CO in CHF, racemic mixture cancers out alpha
Albuterol, pirbuterol, terbutaline
Adrenergic Agonist- B2 selective
Short acting bronchodilators (less cardiac stimulation)
Salmeterol and formoterol
Adrenergic Agonist
B2 selective agents
B2 long acting bronchodilator
Amphetamine
Indirect adrenergic agonist
CNS stimulant, increases BP by alpha effect of vasculature, beta effect on heart
Ephedrine
Mixed action
Alpha, beta, and CNS stimulant
Use- nasal sprays due to local vasoconstrictor activity; urinary incontinence
Long DOA
Phenoxybenzamine
Adrenergic antagonist Alpha blocker
Irreversible, nonselective and noncompetitive block, tx of pheochromocytoma to preclude HTN crisis that can result from manipulating tissue.
Phentolamine
Adrenergic antagonist Alpha blocker
Competitive, nonselective block (alpha 1 and 2 response is more E being created and alpha 1 decreased vasoconstriction)
Prazosin, doxazosin, terazosin
Adrenergic antagonist Alpha blocker
Selective alpha1 blocker- used for vasodilation
Tx- hypertension, BPH, CHF by relaxing the arterial and venous smooth muscle and decreased PVR.
Tamsulosin
Adrenergic antagonist Alpha blocker
Tx of BPH (benign prostate hyperplasia)
Inhibitor of Alpha 1 receptor on smooth muscle of prostate (decreases tone of bladder neck and prostate and improves urine flow.)