Drugs and Pharmacology Overview PDF

Here is the converted text from the images into a structured Markdown format: ### Page 1: Geriatric Patients * More sensitive to drugs than younger adults * Wider variation in response #### Absorption: * \% of an oral dose that is absorbed does not change. * Rate of absorption may slow....

Here is the converted text from the images into a structured Markdown format: ### Page 1: Geriatric Patients * More sensitive to drugs than younger adults * Wider variation in response #### Absorption: * \% of an oral dose that is absorbed does not change. * Rate of absorption may slow. #### Distribution: * Increased % body fat $\implies$ storage for lipid-soluble drugs * $\downarrow \%$ of lean body mass. * $\downarrow$ total body water $\implies$ concentration $\uparrow$, more intense effects. * $\downarrow$ Serum albumin $\implies \uparrow$ levels of free drugs. * Blood-brain barrier is less intact. #### Metabolism: * Hepatic metabolism declines with age. * Half-life of some drugs may increase + prolonged responses. * Responses to oral drugs may be enhanced. #### Excretion: * Renal function decline. * Drug accumulation secondary to reduced renal excretion is the most important cause of adverse drug reactions in the elderly. * Alterations in receptor properties (some). * 7x more likely to have an adverse drug reaction. * Most (75%) of non-adherence cases are intentional. ### Page 2: Drugs in Pediatrics * More sensitive to drugs. * Greater individual variation. * Many drugs used in pediatrics have never been tested in pediatrics*. Increased sensitivity in infants due to the immature state of: * Absorption. * *Protein binding of drugs. * Blood-brain barrier. * Hepatic metabolism. * Renal drug excretion. #### Absorption: * Delayed gastric emptying, higher pH in the stomach. * IM administration slow + erratic first few days of life. * Increased toxicity because of thin skin. #### Distribution: * Low albumin levels (until 10-12 months), fewer protein-binding sites. * Immature blood-brain barrier. #### Metabolism: * Hepatic metabolism low (mature by one year). #### Excretion: * Low at birth (adult level by one year). *Metabolize drugs faster* Age 1+ ### Page 3: Drugs in Pregnancy/Lactation #### Physiologic Changes * Absorption: may $\uparrow$ because tone and mobility of bowel decrease. * Distribution: volume of distribution increases for some drugs as plasma volume doubles. * Metabolism: $\uparrow$ for some drugs, like antiepileptics. * Excretion: 3rd trimester renal blood flow is doubled $\implies$ excretion accelerated $\uparrow$. *Levels of many drugs decrease doses need to be increased.* *All drugs can cross the placenta (small, lipid-soluble easiest).* #### Teratogenesis * Gross malformations: first trimester (up to ten weeks after the last menstrual period) are most vulnerable. * Antiepileptic drug may be a suspected teratogen. * Preimplantation period: conception $\implies$ week 2. * Embryonic period: week 3 $\implies$ 8. * Fetal period: week 9 $\implies$ delivery. ### Page 4: Adrenergic Agonists cont.4 - Ephedrine: * Mech. of act: activates alpha 1, alpha 2, beta 1, beta 2. * Med. Uses: asthma $\implies$ bronchodilation. * Shock * Anesthesia-induced hypotension. * Adverse effects: * Hypertension. * Dysrhythmias. * Angina. * Hyperglycemia. * Insomnia. #### Normal Vital Signs * Respiratory Rate: 12-20 breaths per minute. * Heart Rate: 60-100 bpm. * Blood Pressure: 120 systolic/ 80 diastolic. * Serum creatine - LOW = bad kidney function. * LFTs - HIGH = bad liver function. * GFR - LOW = bad kidney function. ### Page 5: Adrenergic Agonists cont. 3 #### Non-Catecholamines * Can be given orally > slowly metabolized by MAO * Longer half-life. * Can cross the blood-brain barrier. Drugs: albuterol, phenylephrine, ephedrine (APE). #### Albuterol * Mech. of act: activates beta 2, beta 1 at larger doses. * Med. Uses: asthma. * Adverse effects: minimal at therapeutic doses. * Tremors * Tachycardia #### Phenylephrine: * Mech. of act: activates alpha 1. * Med. Uses: reduces nasal congestion. * Adverse effects: * Hypertension * Necrosis following extravasation. ### Page 6: Adrenergic Agonists cont. 2 #### Dobutamine * Mech. of act: activates beta 1, alpha 1, alpha 2, beta 2 weakly. * Med. Uses: states of low cardiac output (strong inotropic effect, $\uparrow$ force of contraction without much of HR). * Adverse effects: tachycardia. #### Dopamine a $\implies$ b $\implies$a * Mech. of act: Low $\implies$ Dopamine * Moderate $\implies$ dopamine + beta 1 * Very High $\implies$ Dopamine, beta 1, alpha 1 * Med. Uses: Shock ($\uparrow$ Cardiac Output + $\uparrow$ Blood flow kidneys), heart failure ($\uparrow$ force contraction). * Adverse effects: * Tachycardia * Dysrhythmias * anginal pain * necrosis following extravasation. * Important considerations: (all ENIDD) * MAO inhibitors, tricyclic antidepressants, certain general anesthetics. * *Dopamine: diuretics* ### Page 7: Adrenergic Agonists Cont. #### Norepinephrine * Mech of act: activates $\alpha1$, $\alpha2$, $\beta1$ * Med. Uses: hypotensive states, cardiac arrest * Adverse effects: * Hypertension * Dysrhythmias * Angina * Necrosis following extravasation #### Isoproterenol * Mech of act: activates $\beta1$, $\beta2$ * Med. Uses: AV heart block, cardiac arrest * Adverse effects: * Dysrhythmias * Angina * Hyperglycemia ### Page 8: Adrenergic Agonists #### Catecholamines * Cannot be used orally (destruction by liver) * Brief duration of action (enzymes MAO+COMT) * Cannot cross blood-brain barrier (polar molecules) * Drugs: epinephrine, norepinephrine, isoproterenol, dopamine, dobutamine (ENIDD) #### Epinephrine * Mech of act: activates $\alpha1$, $\alpha2$, $\beta1$, $\beta2$ * Med. Uses: delays absorption of local anesthetic, elevates blood pressure, mydriasis (pupil dilation), restores cardiac fuction, anaphylactic shock * Adverse effects: * Hypertensive crisis * Dysrhythmias * Angina * Necrosis following extravasation * Hyperglycemia ### Page 9: Alpha Blockers - SIN #### Prazosin * Mech of Act: cause direct blockade of $\alpha1$ receptors * Med Uses: essential (primary) hypertension $\rightarrow$ vasodilation, reversal of toxicity from $\alpha1$ agonists $\rightarrow$ blocks, benign prostatic hyperplasia $\rightarrow$ contraction of bladder neck and prostatic capsule * Major Adverse Effects: orthostatic hypotension ($\downarrow$BP sit $\rightarrow$ stand), reflex tachycardia ($\uparrow$HR from $\downarrow$BP), nasal congestion $\rightarrow$ vasodilation inhibits ejaculation, sodium retention + $\uparrow$ blood volume ($\downarrow$BP promotes renal retention of Sodium + water) * Important Interactions: avoid comining with other alpha-blockers Recognize this Alpha-Blocker: #### Prazosin: * Only approved for hypertension * Can also benefit patients with BPH ### Page 10: Beta Blockers cont. - LOL #### Important interactions: | **Beta 1 block** | **Beta 2 block** | | :----------------------------------------- | :-------------------------------------- | | patients with: | calcium channel blockers ($\downarrow$HR,$\downarrow$ BP) | | ~ sinus bradycardia | Insulin (masks hypoglycemia) | | ~ AV block > 1st degree | patients with: | | ~ heart failure | ~diabetes | | drugs: metoprolol, propranolol | drugs: propranolol | Recognize these beta-blockers: #### Metoprolol: * blocks Beta 1 receptors * safer for patients with diabetes + respiratory disorders #### Propranolol: * blocks Beta I and Beta 2 receptors * caution in patients with diabetes + asthma/COPD ### Page 11: Acetylcholinesterase Inhibitor #### Physostigmine * Mech of Act: inhibits acetylcholinesterase (enzyme that promotes the degradation of acetylcholin-ACh) as ACh builds up it competes with the antimuscarint agent for receptor binding $\longrightarrow$ reversing excessive muscarintc blockade. * Med. Uses: \*treats anticholinergic poisoning* #### Beta Blockers - LOL * Mech of act: causes blockade of betal and/or beta2 receptors * Med. uses: angina pectoris $\longrightarrow$ $\downarrow$cardiac workload * Hypertension $\longrightarrow$ NOT known * Tachycardia $\longrightarrow$ $\downarrow$HR * Cardiac dysrhythmias $\longrightarrow$ $\downarrow$rate of sinus nodal discharge * Velocity of conduction AV node * Myocardial infarction $\longrightarrow$ $\downarrow$HR + $\downarrow$ force of contraction * Heart failure | **Adverse Effects** | | | :------------------------------------------------ | :---------------------------------------------------- | | Beta 1 block | Beta 2 block | | ~ Bradycardia | ~ bronchoconstriction | | ~ Heart failure (crackles in lungs,edema, weight gain) | ~ inhibition of glycogenolysis and hypoglycemia unawareness | | ~ AV heart block | | | ~ Rebound cardiac Excitation (taper!) | | ### Page 12: Anticholinergic/Antimuscarinic #### Atropine * Mech of act: blocks muscarinic receptors (ACH) * Med. Uses: bradycardia $\rightarrow$$\uparrow$ HR, ashtma/COPD $\rightarrow$ bronchial dilation, overactivity of bladder $\rightarrow$ relaxes bladder muscle * Major Adverse Effects: * Dry mouth = can't spit * Blurred version = can't see * Urinary retention = can't pee * Constipation = can't shift * Anhidrosis = can't sweat * Tachycardia * Important interactions: * Avoid combining with other drugs capable of causing muscarinic blockade $\rightarrow$ antihistamines, antipsychotics, Tricyclic antidepressants Recognize these anticholinergics: * Tolterodine * Solifenacin ### Page 13: Autonomic (ANS) | | | | :------------------------- | :---------- | | Sympathetic | Parasympathetic | | ↑ HR | ↓ HR | | ↑ BP | ↑ gastric secretions | | Dilation of bronchi | Emptying bladder | | Pupil dialation | Emptying bowel | | Vasoconstriction | Focusing eye near vision | | Mobilize stored energy | Pupil constriction | | Glucose → brain | Bronchoconstriction | | Fatty acids → muscle | | **Receptors** | **Sympathetic** | **Parasympathetic** | | :--------------- | :------------------------------------------------------------------ | | Alpha 1 | Cholinergic/Muscarinic | | Blood vessels | Lots of places | | Vasoconstriction | Turn on faucets | | Ejaculation | Same effects as listed above | | Contraction of bladder | Activated by: Ach | | Neck + prostate | | | Alpha 2 | Dopamine: (Kidney) | | Minimal clinical importance | Dilates renal blood vessels | | Beta 1 | Activated by: epi, norepi, dopamine | | Heart & kidney | | |↑HR | | |↑ Force of Contraction | | |↑ Velocity of Conduction | | |Renim Release | | | Beta 2| | | Bronchi muscles liver | | | Bronchodilation | | | Relax uterine muscle | | | Vasodilation @ working muscles | | | Glycogenolysis @ liver skeletal muscles| |