Geriatric Pet Health Issues & Medications, Part 2

As pets age they are more susceptible to certain conditions that can decrease longevity and diminish the quality of life.  Careful owner observation and regular office exams are critical to detect conditions of aging while they are more easily manageable. If caught early in disease progression, there is a good chance nutritional and pharmaceutical intervention can significantly decrease morbidity.  In our previous post, the effects of aging on the musculoskeletal, cardiovascular, renal, and urinary systems were discussed. To append, this month the increased incidence of ophthalmic issues, endocrine dysfunction, and cancer3 in the geriatric canine and feline will be discussed, as well as available treatments.

 

 Older Cat

Ophthalmic Issues

Many senior cats and dogs develop cataracts as a result of UV exposure (which is greater in high altitude states!), the presence of underlying illnesses such as diabetes10, exposure to radiation (cancer treatment), and possibly even chronic exposure to certain medications like ketoconazole (according to a 1996 study by Paul Da Costa).  Unfortunately there is very little that can be done to treat cataracts; depending on the severity, surgical invervention may be warranted.

Keratoconjunctivitis sicca (KCS) and pannus also increase in frequency for elderly pets, especially in certain canine breeds.3  Dry Eye is frequently treated successfully using anti-inflammatory eye drops.5  In felines, Feline Herpes Virus is a common cause of conjunctivitis and should be ruled out, especially if the patient is a younger feline with concurrent upper respiratory symptoms. The following compounded preparations are commonly requested from Monument Pharmacy to aid in the treatment of companion animal ophthalmic issues: 4,5

 

  • Cyclosporine- ophthalmic drop in corn, olive, or MCT oil; ophthalmic ointment
  • Idoxuridine- ophthalmic ointment
  • Tacrolimus- ophthalmic drop in corn, olive, or MCT oil; ophthalmic ointment
  • Prednisolone- ophthalmic ointment
  • Tetracycline- ophthalmic ointment

 

Endocrine dysfunction

The incidence of endocrine dysfunction in aging pets is skyrocketing, especially hyperthyroidism in felines. It is estimated that over 10% of felines over the age of 10 will develop this condition.  The reason for this sudden increase is unknown, but may be due to environmental and dietary exposure to hormone-disrupting chemicals.  Polybrominated diphenyl ethers (PBDEs) are flame retardants used on many household items and frequently a component of household dust; they are known thyroid hormone disruptors. Soy is also a known thyroid hormone disruptor and is frequently found in pet foods to increase protein content.  Bisphohenol-A (BPA) is used to coat the insides of cans (‘wet’ diets) and is also a known hormone disruptor. Also, too little or too much iodine in the diet can disrupt thyroid function (iodine is a very poorly regulated nutrient in the pet food industry).  Treatment options include surgery, radioactive iodide (I-131), or methimazole (Rx).  Monument pharmacy frequently compounds methimazole for feline patients in the following forms:

 

  • Methimazole- capsule, suspension, transdermal gel

 

Canines are more likely to suffer from hypothyroidism. Most frequently this results from natural atrophy or immune-mediated destruction of the gland. Iodine deficiency or congenital problems are also play a role.  Symptoms a pet may present with include thickening of the skin, hair loss (usually starting on the tail), excessive oily coat -or- dry/brittle coats, weight gain, and lethargy or listlessness.  When performing bloodwork, keep in mind certain breeds (sighthounds/Greyhounds) have lower T4 than the “normal” for most other breeds!  Also, certain drugs such as phenobarbital, potassium bromide, corticosteroids, NSAIDs, propranolol, clomipramine, and sulfa antibiotics can depress T4 secretions, causing false positives for hypothyroid lab results. Treatment most commonly utilizes prescription synthetic levothyroxine or prescription natural thyroid (T3/T4).  Our most commonly requested hypothyroid treatments for canines include the following forms:

 

 

  • Levothyroxine- capsule, suspension, transdermal gel, commercial tablet
  • T3/T4- available as commercial product NatureThroid® (RLC labs)

 

Most commonly found in canines, Cushing’s Disease, or pituitary-dependent hyperadrenocorticism, accounts for ~85% of hyperadrenocorticism cases in middle-aged and older canines. Cushing’s is caused by an adenoma or hyperplasia of the ACTH-producing cells in the pituitary gland.   The remaining 15% of cases are due to adrenal tumors (more common in large breeds).  The most common clinical signs in dogs and cats are polydipsia, polyuria, polyphagia, heat intolerance, lethargy, abdominal enlargement or “potbelly” due to hepatomegaly, panting, obesity, muscle weakness, alopecia, bruising, and recurrent urinary tract infections.  Cats may present with secondary respiratory infections and increased skin fragility.5 Cushing’s is a lifelong condition affecting canines and can often be managed with medications. Regular monitoring is necessary as disease progression necessitates dosing adjustment over time.

 

In addition to surgery or radiation therapy, there are two FDA-approved treatments for hyperadrenocorticism. Trilostane (Vetoryl®) is approved to treat both pituitary- and adrenal-dependent hyperadrenocorticism in dogs. Keep in mind trilostane is contraindicated if there is hepatic or renal disease, and interacts with some cardiac medications.  Selegiline (Anipryl®) is approved to treat only uncomplicated, pituitary-dependent Cushing’s disease in canines.  Some specialty centers are also using mitotane (Lysodren®) to treat Cushing’s in dogs; this drug permanently destroys the layers of the adrenal gland that produce cortisol and requires careful monitoring due to risk of severe side effects.

 

  • Mitotane- capsule, suspension, commercial tablet
  • Selegiline- capsule, suspension, transdermal gel
  • Trilostane (from brand name Vetoryl®)- capsule, suspension

 

 

Cancer
Cancer is the uncontrolled growth of abnormal cells of the body. It can be benign or malignant, localized or metastasized.  According to the American Kennel Club’s Canine Health Foundation, the most common canine cancers include hemangiosarcoma, lymphoma, mammary cancer, mast cell tumors, melanoma, osteosarcoma, prostate cancer, and transitional cell carcinoma. Breeds such as Golden Retrievers, Great Danes, Boxers, Boston Terriers, Bernese Mountain Dogs, Rottweilers, and Saint Bernards are considered “high risk” as they have a higher incidence than other purebred and mixed-breed animals.  According to the Veterinary Cancer Center, cats are less likely to develop cancer than dogs, but it is more likely to be aggressive. The most common types of feline cancer include leukemia/lymphoma (often from the FeLV virus), vaccine-associated fibrosarcoma, mammary cell tumor, mast cell tumor, oral squamous cell, and intestinal adenocarcinoma. There is less breed-specific data is available. However, cats with white ears and heads in particular are prone to skin tumors, and Siamese, Persians, and Bengals are considered “high risk” (Eric Barchas DVM, Catster 22 April 2008).

Depending on the diagnosis, disease progression, and the owner’s wishes, treatment choices include surgery, radiation therapy, chemotherapy, or a combination. There are many chemotherapeutic agents available, many of which can be very harmful to not only the patient, but the owner and household family members as well (due to secondary exposure).  When considering home-treatment protocols, It is of utmost importance to consider the owner’s ability to administer the medication without exposing him/herself (and other family members!) to the chemotherapeutic agent and educating the owner on minimizing environmental exposure (handling of waste, etc).  To protect our employees, Monument Pharmacy offers limited chemotherapeutic agents and many palliative treatments for cancer and related issues (pain, gastrointestinal issues, incontinence, antihistamines, glucocorticoids, etc).

 

  • Chlorambucil- capsule, suspension
  • Cyclophosphamide- suspenion, capsule
  • Mitotane- capsule, suspension, commercial tablet
  • Buprenorphine*- suspension (oil and aqueous), transdermal gel
  • Cetirizine- capsule, suspension, transdermal gel
  • Cisapride- capsule, suspension, transdermal gel
  • Chlorpheniramine- capsule, suspension, transdermal gel
  • Diethylstilbesterol (DES)- capsule, suspension, tablet
  • Diphenhydramine- capsule, suspension
  • Fludrocortisone- capsule, suspension, commercial tablet
  • Hydroxyzine- capsule, suspension
  • Metoclopramide- capsule, suspension, transdermal gel
  • Phenylpropanolamine- capsule, suspension
  • Prednisolone- capsule, suspension, transdermal gel, commercial tablet
  • Prednisone- capsule, suspension, transdermal gel, commercial tablet
  • Piroxicam- capsule, suspension
  • Tramadol*- capsule, suspension, commercial tablet, transdermal gel

 

*Prescriptions for Controlled substances require additional patient-specific information which varies by state. Please consult with a pharmacist for details.

 

“While age itself is not a disease, the aging process induces complex and interrelated metabolic changes that complicate health care.  Management decisions should not be based solely on the age of the patient, as many conditions that affect older pets can be controlled, if not cured.”6

 

For prescribers and their patients, quality means accuracy, consistency, professionalism and service.  At Monument Pharmacy, our licensed pharmacists and certified technicians prepare all of our compounded products with the utmost attention to detail regarding purity, potency, and consistency.  All ingredients are sourced from FDA-licensed suppliers, and compounded prescriptions are prepared according to exacting federal and Colorado state standards.

 

Most Rx orders for compounded medications received prior to 3pm Mountain can be shipped out the same business day. When you call, you will always reach one of our friendly customer care specialists in person, right here in Monument, Colorado.  We will beat others’ compound prices by 10%. Just let us know what you’re quoted or paying elsewhere. As an added value, we are able to ship many prescriptions via USPS first-class mail at no charge!  Our goal is for your service to be second to none.  Feel free to contact us fordetails at 1-800-595-7565.

 

References

  1. Goldston, Richart T, Hoskins, Johnny. Geriatrics & Gerontology of the Dog and Cat. Philadelphia: W.B. Saunders Co, 1995
  2. Senior Pet Care. AVMA. February 2009. Accessed July 2015.
    https://www.avma.org/public/PetCare/Pages/Caring-for-an-Older-Pet-FAQs.aspx
  3. AAHA Senior Care Guidelines for Dogs and Cats. J Am Anim Hosp Assoc 2005;41:81-91.
  4. Plumb, Donald C. Plumb’s Veterinary Drug Handbook, 10th Ed. Stockholm, WI: Pharmavet, Inc., 2008
  5. Kahn, Cynthia; et al.  The Merck Veterinary Manual (10th Edition). Whitehouse Station, NJ:  Merck & Co, Inc. 2010
  6. Senior Care Guidelines (American Academy of Feline Practitioners). Journal of Feline Medicine and Surgery 2009;11:763-778 (accessed at http://jfm.sagepub.com/content/11/9/763.full.pdf)
  7. Becker, M. Caring for older pets and their families. Firstline; August/September 1998; 28-30.
  8. Epstein, M; Kuehn, NF; Landsberg, G; et al. AAHA Senior care guidelines for dogs and cats. Journal of the American Animal Hospital Association 2005; 41(2):81-91.
  9. Fortney, WD (ed). Veterinary Clinics of North America Small Animal Practice: Geriatrics. W.B Saunders Co, Philadelphia, PA; 2005.
  10. Summers, Alleice.  Common Diseases of Companion Animals (3rd Ed).  Philadelphia, PA: Elsevier, 2014

 

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