Pharmacology Flashcards

Question

What is the mechanism of action of ephedrine? What clinical effects can be expected?

Answer 1

Sympathomimetic amine (not strictly a Catecholamine) General cardiovascular stimulant and bronchodilator that functions by stimulating the release of norepinephrine from sympathetic nerve endings. Prolonged use can deplete norepinephrine stores, resulting in tachyphylaxis. Can be administered as boluses or CRI

Answer 2

“Norepinephrine is primarily an α-receptor agonist and is associated with arteriolar and venous constriction. It also exhibits minimal β1-receptor agonist activity (in contrast to phenylephrine and vasopressin, norepinephrine may increase heart rate and contractility). Norepinephrine generally causes vasoconstriction and increases blood pressure, with variable effects on heart rate; cardiac output may increase,16,19-24 decrease,17,24 or remain unchanged.2” Excerpt From Small Animal Critical Care Medicine Deborah Silverstein & Kate Hopper https://books.apple.com/us/book/small-animal-critical-care-medicine/id903782830 This material may be protected by copyright.

Answer 3

“Vasopressin is a noncatecholamine vasoconstrictor acting via the vasopressin V1 receptor that increases intracellular calcium and vasomotor tone (see Chapter 158). It is a pure vasoconstrictor with no direct effect on the heart. Its administration is usually associated with an increase in systemic vascular resistance, a baroreceptor reflex decrease in heart rate, no change in contractility, and no change or a decrease in cardiac output.13,16,29,30-36 Arterial blood pressure is usually increased” Excerpt From Small Animal Critical Care Medicine Deborah Silverstein & Kate Hopper https://books.apple.com/us/book/small-animal-critical-care-medicine/id903782830 This material may be protected by copyright.

Answer 4

“Epinephrine can be used to support cardiovascular dysfunction in critically ill patients, but its therapeutic margin may not be as liberal as that of the other catecholamines (higher incidence of sinus tachycardia, ventricular arrhythmias, and increased lactate level) and it is a potent vasoconstrictor” Excerpt From Small Animal Critical Care Medicine Deborah Silverstein & Kate Hopper https://books.apple.com/us/book/small-animal-critical-care-medicine/id903782830 This material may be protected by copyright.

Answer 5

“Isoproterenol is a potent β-receptor agonist with no α-receptor activity. As such, it is a potent vasodilator and hypotensive agent. In anesthetized dogs, isoproterenol increases heart rate and cardiac output, and decreases blood pressure.8 If isoproterenol is administered very carefully while blood pressure is monitored and maintained, it can provide potent augmentation of forward blood flow and tissue perfusion.” Excerpt From Small Animal Critical Care Medicine Deborah Silverstein & Kate Hopper https://books.apple.com/us/book/small-animal-critical-care-medicine/id903782830 This material may be protected by copyright.

Answer 6

“Consequently, when hypotension is the problem, dopamine is the drug of choice; dopamine is the “pressure” drug of the two. When blood pressure is acceptable, dobutamine is the drug of choice to augment forward flow; dobutamine is the “flow” drug of the two. ” Excerpt From Small Animal Critical Care Medicine Deborah Silverstein & Kate Hopper https://books.apple.com/us/book/small-animal-critical-care-medicine/id903782830 This material may be protected by copyright.

Answer 7

“Heparin acts primarily to limit the conversion of fibrinogen to fibrin by accelerating the action of antithrombin III in inhibiting activated coagulation factors (II, IX, X, XI, and XII). Unfractionated heparin (UFH) has been most commonly used because of its widespread availability and low cost. It should be dosed to prolong the activated partial thromboplastin time (aPTT) 1.5 to 2 times that of baseline. ” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 8

“Fentanyl is commonly used as a constant-rate infusion (CRI) for analgesia in dogs and cats because it has an elimination half-life of approximately 45 minutes” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 9

“Dexmedetomidine, an alpha-2 agonist, is an effective sedative and analgesic (see Chapter 12 and Tables 13.2 and 13.4). Due to its cardiovascular depressant effects, it is typically given as an adjunct with other analgesics. Its effects the alpha-2 receptor in the dorsal horn of the spinal cord, brain stem, and in the periphery. It provides excellent visceral analgesia with a duration of 1 to 2 hours. A microdose CRI (see Table 13.2) can offer a constant and titratable level of analgesia; however, decreased cardiac output may still be seen. Alpha-2 agonists are synergistic with opioids. The effects of alpha-2 agonists can be reversed with atipamezole (see Chapter 12 and Table 13.2).14” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 10

“Tepoxalin (Zubrin) inhibits COX-1, COX- 2, and lipoxygenase, preventing the synthesis of leukotrienes. It is administered orally as a wafer that dissolves in the mouth” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 11

“Amantadine is a dopamine agonist and NMDA receptor antagonist. The potential analgesic effect is mediated through NMDA antagonism. It appears to be most effective in cases of chronic pain and with central sensitization. It undergoes renal excretion in dogs. When used at higher doses, monitor for CNS excitement (see Table 13.2). CNS stimulation is a side effect of the dopamine agonist activity, and it should be used with caution in patients receiving other dopaminergic agents, such as the monoamine oxidase inhibitor selegiline, or agents inhibiting the reuptake of serotonin (i.e., the tricyclic antidepressant amitriptyline and the selective serotonin reuptake inhibitor fluoxetine). When used together, there is the risk of serotonin syndrome. This syndrome can be fatal and is characterized by CNS stimulation, muscle tremors, tachycardia, tachypnea, and hypertension. Hepatic dysfunction may enhance this risk as these agents are metabolized by the CYP 450 pathway. Meperidine, fentanyl, tramadol, and methadone increase the CNS concentration of serotonin and may contribute to serotonin syndrome, although the risk is unknown.20” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 12

“Amitriptyline is a tricyclic antidepressant. It is a selective serotonin reuptake inhibitor leading to increases in synaptic levels of serotonin and norepinephrine. Other actions including sodium channel blockade, NMDA receptor antagonism, and antihistamine activity may contribute to the analgesic effect. Sedation may be a side effect. Overdose may lead to tachycardia, ventricular tachyarrhythmias, hypersalivation, and vomiting. In dogs, hepatic metabolism produces the active metabolite nortriptyline; both it and amitriptyline are excreted unchanged in the urine.20” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 13

“For cats undergoing a declaw procedure, a bupivacaine nerve block can provide analgesia into the postoperative period (see Table 13.2). It is injected subcutaneously, lateral and proximal to the accessory carpal pad to block the dorsal branch of the ulnar nerve, and medial to the accessory pad to block the median nerve and palmar branch of the ulnar nerve. The third site is the dorsal-medial aspect of the proximal carpus to block the superficial branch of the radial nerve.23” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 14

“Lactulose is a synthetic disaccharide that acidifies colonic contents and traps ammonium ions in the lumen (see Box 20.2). It is also an osmotic cathartic that shortens intestinal transit time and reduces the production and absorption of ammonia. Lactulose may be given orally or as a retention enema. Side effects of lactulose administration may include diarrhea, vomiting, anorexia, and increased gastrointestinal loss of potassium and water. ” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 15

“Prostaglandin F2α causes contraction of the myometrium and relaxation of the cervical canal, leading to expulsion of exudate from the uterine lumen. There is a 48-hour lag time before treatment effects are noted; clinical deterioration may occur during that time. Response to treatment consists of a decrease in uterine diameter, cessation of uterine discharge, and resolution of WBC abnormalities. Side effects associated with PGF2α include abdominal pain, emesis, defecation, tachycardia, hypersalivation, dyspnea, panting, and fever. Low-dose treatment with a natural PGF2α such as dinoprost tromethamine is effective in resolving pyometra and has fewer side effects than higher doses. Intravaginal administration of PGF2α was reported successful in 13 of 15 bitches with pyometra and was also associated with less side effects.Synthetic prostaglandins such as cloprostenol have fewer side effects than natural compounds but also produce less uterine contraction and slower evacuation of uterine exudate.” Excerpt From Veterinary Surgery: Small Animal Expert Consult Spencer A. Johnston VMD, DACVS & Karen M. Tobias DVM, MS, DACVS https://books.apple.com/us/book/veterinary-surgery-small-animal-expert-consult/id1250368401 This material may be protected by copyright.

Answer 16

“An additional concern in patients with obstructive biliary disease relates to the effect of mu-agonists (e.g., hydromorphone, morphine) on smooth muscle tone. In human beings with biliary obstruction, these drugs increase both sphincter tone and pain. Mixed agonist-antagonists (e.g., butorphanol; see Tables 12.1 and 13.2) may be preferable as premedicants and analgesics in these patients. After corrective surgery of the biliary obstruction, mu-agonists can be utilized for postoperative analgesia.” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 17

“Triple antibiotic ointment (bacitracin, neomycin, polymyxin) is effective against a broad spectrum of pathogenic bacteria commonly infecting superficial skin wounds. However, its efficacy against pseudomonads is poor. Zinc bacitracin is responsible for enhancing reepithelialization of wounds but can retard wound contraction. Because these drugs are poorly absorbed, systemic toxicosis (nephrotoxicity, ototoxicity, neurotoxicity) is rare. The ointment is more effective for preventing infections and treating mildly infected wounds.” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 18

Effective against most gram-positive and gram-negative bacteria Penetrates necrotic tissue Enhances wound Epithelialization Open friend drug of choice for burn wounds) Dressings may be left in place for seven days. Silver is released slowly, is non-staining, non-irritating and nonsensitizing. Maintains a moist wound environment for Autolytic to bridement Downside: In vitro human studies showed toxicity to keratinocytes and fibroblasts, as well as inhibition of neutrophils and lymphocytes (the addition of aloe vera minimizes this effect)

Answer 19

“Mafenide (hydrochloride or acetate) is a topical sulfa compound available as an aqueous spray most commonly used for burn wounds in humans. It has a broad spectrum against many gram-positive and gram-negative bacteria, including Pseudomonas spp., Clostridium spp., and methicillin-resistant Staphylococcus aureus; it is particularly useful on severely contaminated wounds.” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 20

“Gentamicin sulfate is available as a 1% ointment or powder (Garamycin), but solutions are preferred. Products with an oil-in-water cream base slow wound contraction and epithelialization. It is especially effective in controlling gram-negative bacterial growth (Pseudomonas spp., Escherichia coli, Proteus spp.). It is often used before and after grafting and for wounds that have not responded to triple antibiotic ointment. However, gentamicin in an isotonic solution does not inhibit contraction, and it promotes epithelialization.” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 21

“Acemannan is available as a topical wound hydrogel or a freeze-dried gel form. It is indicated for managing superficial and deep partial-thickness burns, lacerations, dermal ulcers, abrasions, and nonhealing wounds. Acemannan is a β-(1,4) acetylated mannan derived from the aloe vera plant that enhances early stages of healing. Acemannan stimulates macrophages to secrete interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-α), which enhance fibroblast proliferation, neovascularization, epidermal growth and motility, and collagen deposition to form granulation tissue. Acemannan may also bind growth factors, prolonging their stimulating effect on formation of granulation tissue. The freeze-dried form enhances healing over exposed bone and has hydrophilic properties, which help cleanse the wound and reduce wound edema. The most effective time to begin topical application is in the early inflammatory stage of healing with daily application under a bandage, continuing into the repair stage of healing. The greatest effects are seen in the first 7 days of application. Excess granulation tissue can occur, especially with the freeze-dried form, which inhibits wound contraction.” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 22

“Aloe vera gel is extracted from the aloe vera leaf and contains 75 potentially active constituents. Aloe vera has been used on burns because of its antibacterial activity against Pseudomonas aeruginosa. It also inhibits fungal growth. The antiprostaglandin and antithromboxane properties of aloe vera medications are beneficial in maintaining vascular patency and thus helping avert dermal ischemia. Aloe vera medications may also stimulate fibroblastic replication. Aloe vera has the ability to penetrate and anesthetize tissue” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 23

“The carboxypenicillins (e.g., piperacillin/tazobactam) have better gram-negative and anaerobe spectrums than the aminopenicillins, whereas the ureidopenicillins (e.g., mezlocillin) have the best gram-negative spectrums of all the penicillins. ” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 24

“Chloramphenicol (Table 9.2) has broad-spectrum activity against most anaerobic and aerobic bacteria, as well as Ehrlichia spp. and Rickettsia spp., but poor activity against Pseudomonas spp. It is highly lipophilic and penetrates most organs (e.g., CNS, eye, prostate). Although considered bacteriostatic, it often achieves tissue levels high enough to make it bactericidal. It is eliminated by hepatic metabolism and urinary excretion. The drug may cause idiosyncratic fatal anemia in people, but dogs and cats experience only a mild, transient anemia, if that. It inhibits hepatic P450 cytochromes and can thus affect hepatic metabolism of certain other drugs (e.g., propofol, opiates, barbiturates).” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 25

“Tetracyclines are effective against many gram-positive and gram-negative bacteria, including Chlamydia spp., rickettsia, spirochetes, Mycoplasma spp., bacterial L-forms, and some protozoa. They are usually ineffective against staphylococci, enterococci, Pseudomonas spp., and Enterobacteriaceae. Doxycycline (see Table 9.2) is usually the preferred tetracycline in small animal practice because it has fewer side effects, penetrates cells better, and has less resistance develop to it compared with other tetracyclines. It is well distributed to most tissues and achieves good intracellular concentrations, although not to the CNS. Products containing calcium chelate and tetracyclines interfere with oral absorption. Binding of the drugs to calcium can be a problem in young or pregnant animals, and tooth discoloration and inhibited bone growth can occur. Doxycycline is primarily eliminated through the intestines in the dog. Typical indications include tick-borne diseases as well as respiratory and prostatic infections. Doxycycline causes hepatotoxicity in some patients, but its main adverse side effect is related to causing esophagitis after oral administration.NoteTetracyclines are caustic, and it is critical that the patient drink water immediately after swallowing a tablet or capsule (in the case of doxycycline, the patient may eat nondairy food). Otherwise the tablet may lodge in the esophagus[…]” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 26

“Erythromycin is a macrolide that is readily absorbed from the upper gastrointestinal system and diffuses well throughout most tissues. All macrolides tend to accumulate in phagocytic cells and are usually eliminated in the bile. Erythromycin has a narrow spectrum of activity and may be associated with nausea and vomiting because of its prokinetic activity. New derivatives include clarithromycin and azithromycin. Azithromycin (see Table 9.2) is active against aerobic bacteria, such as staphylococci and streptococci, and anaerobes. It also has good activity against Mycoplasma spp. and intracellular organisms, such as Bartonella spp., Toxoplasma spp., and atypical mycobacteria. Absorption of azithromycin after oral administration is high, and it is well tolerated. The drug achieves extremely high tissue concentrations and only needs to be given once daily.” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 27

“Clindamycin (see Table 9.2) is a lincosamide that is primarily eliminated by biliary excretion and achieves excellent concentrations in the skin and bones, as well as high concentrations in white blood cells. It is effective against most anaerobic bacteria, plus it is active against many gram-positive pathogens. Typical indications include intra-abdominal infections, osteomyelitis, discospondylitis, and oral/dental disease. Clindamycin can be used in combination therapy directed at Pseudomonas aeruginosa; it inhibits bacterial adherence to epithelial cells, making it more susceptible to other antibiotics. Clindamycin is effective against toxoplasmosis and Neospora, and it can cause esophagitis if the pill stays in the esophagus (especially in cats).” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 28

“A β-lactam drug should never be mixed in the same syringe, vial, or intravenous (IV) line with an aminoglycoside; mixing the two can result in a chemical reaction that inactivates one or both of the drugs.” Excerpt From Small Animal Surgery E-Book Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984 This material may be protected by copyright.

Answer 29

Broad- spectrum anticonvulsant. Blocks SV2A, a synaptic vesicle protein. Minimal protein binding and excreted via kidneys, so safe for liver disease.

Answer 30

Ammonia is produced by G.I. microbiotita it is typically converted to urea and glutamine via the urea cycle in the normal liver. The abnormal blood flow associated with PSS results in ammonia accumulation. Lactulose is metabolized by colonic bacteria, resulting in the formation of carbon dioxide, lactic, formic and acetic acids. The resulting acidic environment promotes the conversion of ammonia to ammonium, which is not readily absorbed and becomes ion trapped and expelled in the feces.

Answer 31

Metronidazole - broad coverage against urease-producing bacteria; concentration dependent. Ampicillin - time dependent, not as broad-coverage against urease-producing bacteria as metronidazole but no concerns over neurotoxicity. Ampicillin is preferred over amoxicillin due to its lower oral bioavailability (Minimizes systemic absorption)

Answer 32

Intravenous diazepam contains a propyleneglycol carrying agent that requires hepatic metabolism

Answer 33

Post attenuation seizures are believed to be caused by an imbalance in the endogenous inhibitory CNS benzodiazepine agonist levels. Propofol undergoes hepatic microsomal enzyme metabolism, like many drugs, but also has extrahepatic metabolic sites. It is believed to be beneficial for the treatment of status epilepticus because of it GABA activity at a different site from benzodiazepines. propofol is protein-bound. Those adjustments must be made in patients with low albumin.

Answer 34

Phenobarbital has a lower lipid solubility and may take up to 30 minutes to reach therapeutic concentrations (benzodiazepines are much faster). Phenobarbital has also been shown to cause hepatic injury after long term administration in dogs.

Answer 35

Nonsteroidal anti-inflammatories One study found a 38.5% mortality rate in dogs with intrahepatic shins treated with NSAIDs perioperatively, compared with 2.4% in dogs not treated with NSAIDs. All dogs in the study died because of confirmed or suspected gastroduodenal ulcerations.

Answer 36

Omeprazole has been reported to reduce gastric acid secretion by 80 to 95%

Answer 37

Omeprazole. Studies regarding intrahepatic PSS have demonstrated that up to 21% of dogs have lifelong risk for GI ulceration with significantly shorter survival time. Specifically for dogs undergoing treatment of intrahepatic PSS Prior to anti-acid therapy, 50% of deaths were attributed to G.I. bleeding. Lifelong anti-acid therapy reduced this rate to 4%

Answer 38

SAMe is an endogenous coenzyme necessary for various hepatic functions including transmethylation and decarboxylation, as well as the production of glutathione, a crucial hepatic antioxidant.

Answer 39

Neurokinin 1 receptor antagonist. Binds Substance P in emetic center in brain.

Answer 40

Tricyclic antidepressant Alpha-2 adrenergic receptor antagonist Blocks presynaptic alpha-2, serotonin (5HT) and histamine receptors

Answer 41

Lack of gag reflex Vocalization Tremors Sialorrhea Stupor Bilateral miosis Intermittent hippus (rhythmic oscillation of the pupil)

Answer 42

Cardiovascular dysfunction Coagulopathy Hemolysis Thrombocytopenia Acute kidney injury Hypertension (due to increased catecholamines?)

Answer 43

Phosphodiesterase III receptor inhibitor, increasing amounts of circulating cyclic AMP and co sequently epinephrine. Also suppresses the production of inflammatory mediators and histamine release. May stimulate mucocilliary system and help clear mucous.

Answer 44

Appears to suppress Adenosine receptors (like caffeine), leading to CNS stimulation in dose-dependent fashion

Answer 45

Stimulates metabolic changes via GH and IGF-1 Mimics the effect of ghrelin, a naturally occurring hormone Approved for long term use in cats Tested and approved for use in cats with CRD Increases food intake

Answer 46

Positive inotrope - increases Ca++ binding to myofibrils Vasodilator - phosphodiesterase inhibitor

Answer 47

Amlodipine

Answer 48

No effect up to two weeks, but delayed healing if extended to 8 weeks. Radiographic healing did not differ between dogs without carprofen and those with 2-week administration of carprofen (P =.9923).However, tibias of dogs without carprofen and those with 2-week administration of carprofen were more healed compared with those in the 8-week-carprofen group at 4 and 8 weeks after surgery (P = .0011). No treatment effect was detected by cartilage:callus ratio or BMD.

Answer 49

1 minute 90 minutes

Answer 50

1 minute 240 minutes

Answer 51

1) Oral tolerization: The exposure of the GI tract Payer patches to small amounts of antigen leading to gradual desensitization through bystander suppression. 2) Clonal Anargy: The exposure of the GI tract Payer patches to large amounts of antigen, converting overactive Th1 lymphocytes into a state of non-reactivity.