Today's Veterinary Practice

JAN-FEB 2018

Today's Veterinary Practice provides comprehensive information to keep every small animal practitioner up to date on companion animal medicine and surgery as well as practice building and management.

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67 JANUARY/FEBRUARY 2018 ● TVPJOURNAL.COM FEATURES buffers consumes hydrogen ions, resulting in an alkalinizing effect. The lactate in LRS is metabolized by the liver; thus, it is a suboptimal choice for patients with hepatic dysfunction or diabetic ketoacidosis because they will not be able to convert lactate to bicarbonate. Neonates are able to use lactate as a fuel source, making LRS the preferred fluid choice for young patients. Many available crystalloids are buffered solutions meant for fluid replacement (eg, Plasmalyte-A, Normosol-R). For longer-term treatment of patients receiving IV fluids, maintenance fluids (eg, Plasmalyte-56, Normosol-M) are solutions that contain lower sodium and higher potassium concentrations to meet maintenance needs. These solutions use dextrose to increase the osmolality of what would otherwise be a hyposmolar fluid. In practice, replacement fluids are frequently used as maintenance fluids and are often well tolerated in patients that do not have underlying conditions, such as cardiac or renal disease, that make them unable to handle the excess sodium. In contrast, 0.9% saline is an unbuffered isotonic crystalloid. Although the tonicity of 0.9% saline is similar to that of plasma, the pH is relatively low (5.5) and the solution contains no electrolytes other than sodium and chloride. Isotonic saline is the fluid of choice for treating hypochloremic metabolic alkalosis because the acid–base disturbance cannot be resolved without correction of chloride. It also promotes calciuresis and so can be used in the treatment of hypercalcemia. Hypotonic Hypotonic crystalloids are useful for treating patients with hypotonic fluid losses that result in hypernatremia or patients that have renal disease and cannot excrete the salt load of balanced isotonic solutions. Two commonly used hypotonic solutions are 0.45% saline and 5% dextrose in water (D5W). The former has an osmolarity of 154 mOsm/L, approximately half the normal plasma osmolarity in dogs and cats. D5W has a high osmolarity at 250 mOsm/L, but the dextrose in solution is rapidly metabolized upon infusion, resulting in infusion of what is essentially free water. Hypertonic Hypertonic saline is the primary hypertonic fluid administered in small animal medicine. Hypertonic saline from 3-7.5% is primarily used during resuscitation in hypovolemic shock and to decrease intracranial pressure. Administration of hypertonic saline results in free water shifting from the interstitial space into the intravascular space, expanding the extracellular volume by approximately 3 times the volume administered. 3,6 Movement of fluid into the intravascular space results in interstitial and intracellular dehydration, so a hypertonic saline bolus should be followed by a bolus of isotonic crystalloid, although this is not necessary if used to treat cerebral edema. The intravascular expansion is short lived, lasting approximately 30 minutes before redistribution. 3 Because the effect is transient, hypertonic saline can be combined with colloid solutions to prolong time present in the intravascular space. In addition to intravascular expansion, hypertonic saline increases cardiac output and tissue perfusion through a weak positive inotropic effect, reduction of endothelial swelling, and arteriolar vasodilation. 3 CAUTION: Federal (US) law restricts this drug to use by or on the order of a licensed veterinarian. BRIEF SUMMARY: Please consult package insert for complete product information. Indications: For use in dogs to prevent canine heartworm disease by eliminating the tissue stage of heartworm larvae (Dirofilaria immitis) for a month (30 days) after infection and for the treatment and control of roundworms (Toxocara canis, Toxascaris leonina), hookworms (Ancylostoma caninum, Uncinaria stenocephala, Ancylostoma braziliense), and tapeworms (Dipylidium caninum, Taenia pisiformis). WARNINGS: For use in dogs only. Keep this and all drugs out of reach of children. In safety studies, testicular hypoplasia was observed in some dogs receiving 3 and 5 times the maximum recommended dose monthly for 6 months (see Animal Safety). In case of ingestion by humans, clients should be advised to contact a physician immediately. Physicians may contact a Poison Control Center for advice concerning cases of ingestion by humans. PRECAUTIONS: Use with caution in sick, debilitated, or underweight animals and dogs weighing less than 10 lbs (see Animal Safety). The safe use of this drug has not been evaluated in pregnant or lactating bitches. All dogs should be tested for existing heartworm infection before starting treatment with IVERHART MAX Chewable Tablets, which are not effective against adult D. immitis. Infected dogs should be treated to remove adult heartworms and microfilariae before initiating a heartworm prevention program. While some microfilariae may be killed by the ivermectin in IVERHART MAX Chewable Tablets at the recommended dose level, IVERHART MAX Chewable Tablets are not effective for microfilariae clearance. A mild hypersensitivity-type reaction, presumably due to dead or dying microfilariae and particularly involving a transient diarrhea, has been observed in clinical trials with ivermectin alone after treatment of some dogs that have circulating microfilariae. ADVERSE REACTIONS: In clinical field trials with ivermectin/ pyrantel pamoate, vomiting or diarrhea within 24 hours of dosing was rarely observed (1.1% of administered doses). The following adverse reactions have been reported following the use of ivermectin: depression/lethargy, vomiting, anorexia, diarrhea, mydriasis, ataxia, staggering, convulsions and hypersalivation. ANIMAL SAFETY: Studies with ivermectin indicate that certain dogs of the Collie breed are more sensitive to the effects of ivermectin administered at elevated dose levels (more than 16 times the target use level of 6 mcg/ kg) than dogs of other breeds. At elevated doses, sensitive dogs showed adverse reactions which included mydriasis, depression, ataxia, tremors, drooling, paresis, recumbency, excitability, stupor, coma and death. No signs of toxicity were seen at 10 times the recommended dose (27.2 mcg/lb) in sensitive Collies. Results of these studies and bioequivalence studies support the safety of ivermectin products in dogs, including Collies, when used as recommended by the label. In a laboratory safety study, 12-week-old Beagle puppies receiving 3 and 5 times the recommended dose once weekly for 13 weeks demonstrated a dose-related decrease in testicular maturation compared to untreated controls. HOW SUPPLIED: IVERHART MAX Chewable Tablets are available in four dosage strengths for dogs of different weights. Each strength comes in a box of 6 chewable tablets, packed 10 boxes per display box. STORAGE INFORMATION: Store at 20°C -25°C (68°F-77°F), excursions permitted between 15°C-30°C (59°F-86°F). Protect product from light. For technical assistance or to report adverse drug reactions, please call 1- 800- 338- 3659. Manufactured by: Virbac AH, Inc. Fort Worth, TX 76137 NADA 141-257, Approved by FDA IVERHART MAX is a registered trademark of Virbac Corporation. © 2017 Virbac Corporation. All Rights Reserved. 3/17

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