7 Medicines and Pharmacology Flashcards
Requirements for skin absorption
Based on lipid solubility through the epidermis
Requirements for CSF absorption
Non-ionized, lipid-soluble drugs
Why can you not use sulfonamides in newborns?
Displaces unconugated bilirubin from albumin in newborns
Where are tetracycline and heavy metals stored?
Bone
0 order kinetics?
Constant amount of drug is eliminated regardless of dose
1st order kinetics?
Drug eliminated proportional to dose
How long does it take for a drug to reach a steady state?
5 half-lives
Volume of distribution?
Amount of drug in the body divided by the amount of drug in plasma or blood
Drugs with high VOD have higher concentrations in extravascular compartment (i.e. fat tissue) compared to intravascular concentrations
Bioavailability
Fraction of unchanged drug reaching the systemic circulation IV drugs - 100% PO drugs (less)
ED50
Drug level at which desired effect occurs in 50% of patients
LD50
Drug level at which death occurs in 50% of patients
Hyperactive
Effect at an unusually low dose
Tachyphylaxis
Tolerance after only a few doses
Potency
Dose required for effect
Efficacy
Ability to achieve results without untoward effect
Phase I drug metabolism
Hepatocyte smooth endoplasmic reticulum
Demethylation, oxidation, reduction,hydrolysis reactions
Mixed function oxidases
Requires NADPH/oxygen
Phase II drug metabolism
Hepatocyte smooth endoplasmic reticulum
Glucuronic acid and sulfates attached
Forms water-soluble metabolite - usually inactive and ready for excretion
Biliary excreted drugs may become deconjugated in intestines with reabsorption, sometimes in active form
Inhibitors of P450
Cimetidine Isoniazid Ketoconazole Erythromycin Cipro Flagyl Allopurinol Verapamil Amiodarone MAOIs Disulfiram
Inducers of P450
Cruciform vegetables ETOH Insecticides Cigarette smoke Phenobarbital (barbiturates) Dilantin Theophylline Warfarin
Polar drugs
Ionized
Water soluble
More likely to be eliminated in unaltered form
Nonpolar drugs
Non-ionized
Fat soluble
More likely metabolized before excretion
Gout
Uric acid buildup
End product of pruine metabolism
Tx: Colchicine, Indomethacin, Allopurinol, Probenecid
Colchicine
Anti-inflammatory
Binds tubulin and inhibits migration of WBCs
For Gout
Indomethacin
NSAID
Inhibits prostaglandin synthesis (reversible cyclooxygenase inhibitor)
For Gout
Allopurinol
Xanthine oxidase inhibitor
Blocks uric acid formation from xanthine
For Gout
Probenecid
Increases renal secretion of uric acid
For gout
Cholestyramine
Binds bile acids in gut - forcing body to make more bile acids from cholesterol
Can bind vitamin K and cause bleeding tendency
For hyperlipidemia
Statins
HMG-CoA reductase inhibitors
Can cause liver dysfunction, rhabdomyolysis
For hyperlipidemia
Niacin
Inhibits cholesterol synthesis
Can cause flushing (Treat with ASA)
For hyperlipidemia
Promethazine (Phenergan)
Antiemetic
Inhibits dopamine receptors
AE: Tardive dyskinesia (treat with benadryl)
Metoclopramide (Reglan)
Prokinetic
Inhibits dopamine receptors
Can be used to increase gastric and gut motility
Ondansetron (Zofran)
Antiemetic
Central-acting serotonic receptor inhibitor
Omeprazole
Anti-acid
Proton pump inhibitor
Blocks H/K ATPase in stomach parietal cells
Ocretotide
Long-acting somatostatin analogue
Decreases gut secretions
Digoxin
Inhibits Na/K ATPase - increasing myocardial calcium
Slows atrial-ventricular conduction, ionotrope
AE: Decreases blood flow to intestines - mesenteric ischemia; Hypokalemia (precipitate arrhythmias/AV block); yellow hue, fatigue, arrhythmias
NOT cleared by dialysis
Amiodarone
Good for acute atrial and ventricular arrhythmias
AE: pulmonary fibrosis with prolonged use, hypo/hyperthyroidism
Magnesium
Used to treat torasdes de pointes (ventricular tachycardia)
Adenosine
Causes transient interruption of the AV node
ACE inhibitors
Can prevent CHF after MI
Can prevent progression of renal dysfunction in HTN, DM
Can precipitate renal failure in renal artery stenosis
Best single agent to improve survival in patients with CHF
ACE inhibitors
Beta-blockers
Improve survival in severe LV failure
Reduces risk of MI and afib postoperative
Best single agent to improve survival in patients after MI
Beta-blockers
Atropine
Acetylcholine antagonist
Increases heart rate
Metyrapone
Aminoglutethimide
Inhibits adrenal steroid synthesis
Used in patients with adrenocortical CA
Leuprolide
Analogue of GnRH and LHRH
Inhibits release of LH and FSH from pituitary when given continuously
Used in patients with metastatic prostate cancer
NSAIDs
Inhibit prostaglandin synthesis and leads to decrease in mucus and HCO secretion and increased acid production
Misoprostol
PGE1 derivative
Protective prostaglandin
Consider use in patients on chronic NSAIDs
Haldol
Antipsychotic Inhibits dopamine receptors Extrapyramidal cells (treat with benadryl)
ASA poisoning
Symptoms: Tinnitus, headaches, nausea, vomiting 1st - respiratory alkalosis 2nd - metabolic acidosis Treatment - supportive
Most common adverse effect of gadolinium
Nausea
Most common side effects of iodine contrast
Nausea
requiring medical treatment - dyspnea
Treatment of tylenol overdose?
N-acetylcysteine
