Veterinary : Urology
Treatment for Urinary Incontinence
Diethylstilbestrol (DES) has been used to treat estrogen responsive
incontinence in spayed female dogs. The use of DES is contraindicated
in cats as daily use has resulted in pancreatic, hepatic, and cardiac
Dose for dogs:
Initially 0.1-1.0 mg PO daily for 3-5 days, followed by maintenance
therapy of approximately 1 mg PO per week. Some animals may require
much higher initial dosages to obtain a response. DES can be given
PO to female dogs at 0.1-0.3 mg/kg/day for 7-10 days, followed by
a similar dose once weekly. Dogs should be maintained at the lowest
possible dose because bone marrow suppression can develop when diethylstilbestrol
is given in high doses. 1,4
When therapy is chronic or high dosages are used, packed cell volumes,
white blood cell counts, and platelet counts should be done at least
monthly. Liver function tests should be done at baseline, one month
after therapy, and repeated 2 months after cessation of therapy if
Clients should be informed to contact the veterinarian if signs
and symptoms of lethargy, diarrhea, vomiting, abnormal discharge
from vulva, excessive water consumption and urination or abnormal
bleeding occur. DES is not for human consumption and should be dispensed
only in child-resistant containers and stored in a secure location.1
DES is not currently commercially available;
however, the medication can be prepared by a compounding pharmacy.
Phenylpropanolamine (PPA) is a weak alphaagonist that increases
urethral sphincter tone and produces closure of the bladder neck,
and is used to treat urethral sphincter hypotonus and resulting incontinence
in dogs and cats.
Dogs: 1.1 mg/kg PO every 8 hours Cats: 12.5mg
PO every 8 hours
The effect is short-lived, and the dose needs to be
titrated to effect. “Dogs that are older at the onset of
clinical signs (median 5 years) and those with a longer period
from the time of ovariohysterectomy to the onset of urinary incontinence
(median 2.5 years) respond best. PPA is preferred to ephedrine
because side effects are less severe; ephedrine has greater cardiovascular
side effects and it tends to lose effectiveness over time.”2 In a multicenter,
blinded, placebo-controlled trial, 50 dogs that presented with clinical
signs consistent with urinary sphincter mechanism incontinence were
treated for 28 days with either PPA (1 mg/kg three times daily) or
placebo. At day 28, 85.7 per cent of PPA-treated cases had no episodes
of unconscious urination compared with 33.3 per cent of placebo-treated
Potential side effects include restlessness, irritability,
hypertension and anorexia. Numerous drug interactions exist.
In November2000, human PPA preparations were removed from the market
due to reports of serious side effects in humans. PPAcontinues to
be available as a bulk chemical for veterinary use only.
1 Veterinary Drug Handbook, 3rd
edition, Donald C. Plumb, ed. pp.193-5, and 508-9
2 Handbook of Veterinary Drugs, 2nd edition, pp. 277-8
3 J Small Anim Pract. 2002 Nov;43(11):493-6
here to access the PubMed abstract of this article.
Per your prescription, we can compound customized
dosage forms to meet the specific needs and flavor/texture preferences
of each animal.
Piroxicam for Canine Bladder Cancer
Traditional chemotherapy (using cisplatin, carboplatin,
adriamycin, and others) has been used in canine Transitional Cell
Carcinoma (TCC). The response has been rather disappointing with <20%
of dogs having remission.
Interest in non-steroidal anti-inflammatory (NSAID)
therapy began when dogs with various forms of spontaneous cancer
had remission while receiving the NSAID piroxicam for pain control,
and no other therapy. Two of the first dogs treated (one with
metastatic carcinoma, one with undifferentiated sarcoma) had advanced
cancer and had remission of their cancer when only receiving piroxicam.
This has led to numerous studies of piroxicam in animals with cancer
at Purdue University Veterinary Teaching Hospital (PUVTH). In an
attempt to improve the response of TCC to therapy, PUVTH conducted
a study comparing chemotherapy (cisplatin) alone to chemotherapy
plus piroxicam. The combination of cisplatin and piroxicam was more
effective against the cancer, but the combination treatment caused
a rise in BUN. In several instances, the cisplatin therapy was withdrawn
(so as to not cause renal damage) while the tumors were still shrinking.
In a phase I study of piroxicam in 62
dogs with various histopathologically confirmed, measurable tumors,
gastrointestinal toxicity was dose-related and dose limiting, but
anti-tumor activity occurred at lower, less toxic doses of piroxicam.
Partial remission occurred in 8 dogs, including 3 of 10 dogs with
TCC. A phase II clinical trial of piroxicam in dogs with histologically
confirmed, measurable, nonresectable TCC was performed. The dogs
lived at home with their owners and were evaluated at the PUVTH
at monthly intervals. Piroxicam was given orally at a dosage of
0.3 mg/kg every 24 hours (the accepted canine dosage prior to this
trial). Tumor response in 34 dogs included 2 complete remissions
(CR), 4 partial remissions (PR), 18 stable disease (SD), and 10
progressive disease (PD). Piroxicam therapy was generally well
tolerated, with gastrointestinal toxicity noted in six dogs and
renal papillary necrosis in two dogs. The median survival was 180
days. Fifty-five additional dogs were treated with piroxicam, and
tumor response included 2 CR, 7 PR, 32 SD, and 14 PD.
It is not known how long dogs with TCC that are not
treated will live. Survival is affected by the growth rate of the
tumor, the exact location of the tumor within the bladder, and whether
the tumor has metasticized. The median survival in dogs treated with
cisplatin or carboplatin at PUVTH was 130 days. Median survival with
piroxicam treatment in 55 dogs with TCC was 190 days. The survival
times in all of these studies, however, vary tremendously from only
a few days to more than one year. Longer survival times have
been reached when chemotherapy is combined with piroxicam, but the
optimal combination treatment is still being determined.
Cancer Chemother Pharmacol 1992;29:214-218
J Vet Intern Med 1994;8:273-278
Cancer Chemother Pharmacol 2000;46:221-226
here to access the PubMed abstract of this article.
Urologic Oncology 2000;5:47-59
Citrate Salts as Alkalinizing Agents
Citrate salts are a source
of bicarbonate, but are much more palatable than bicarbonate preparations. “They
are used as urinary alkalinizers when an alkaline urine is desirable
and in the management of chronic metabolic acidosis accompanied with
conditions such as renal tubular acidosis or chronic renal insufficiency.
Potassium citrate alone has been used for the prevention of calcium
oxalate uroliths. The citrate can complex with calcium thereby decreasing
urinary concentrations of calcium oxalate... When urine is alkalinized
by citrate solutions, excretion of certain drugs (e.g. quinidine,
amphetamines, ephedrine, ...tetracycline) is decreased, and excretion
of weakly acidic drugs (e.g. salicylates) is increased. The solubility
of ciprofloxacin and enrofloxacin is decreased in an alkaline environment
[and patients] should be monitored for signs of crystalluria.” (Plumb’s Veterinary
Drug Handbook, 2nd ed.) In combination with potassium
citrate preparations, these agents may lead to severe increases in
serum potassium levels: NSAIDs, ACE-inhibitors, cyclosporine, digitalis,
heparin and others.
Fludrocortisone is a long-acting corticosteroid with potent
mineralocorticoid and moderate glucocorticoid activity. It is used
in small animal medicine for the treatment of adrenocortical insufficiency,
where it promotes sodium retention and urinary potassium secretion.
It is commercially available only as the human product, a tablet
containing 0.1 mg fludrocortisone acetate. The maintenance
therapy for animals (particularly dogs) can require administration
of multiple tablets for each daily dose. Therefore, it may
be more convenient for owner and animal to administer fludrocortisone
acetate as a flavored suspension, or single flavored solid dosage
Aluminum Hydroxide for Hyperphosphatemia
For dogs and cats, aluminum hydroxide is initially
dosed at 30 - 90 mg/kg orally one to three times daily. A preparation
that can be mixed with food may be preferred as it is more easily
dispersed throughout ingesta. Dosage must be individualized, and
serum phosphate levels should be evaluated at 10-14 days to determine
Veterinary Drug Handbook, 3rd edition, Donald C. Plumb,
editor. pp. 48-49
Calcitriol for Chronic Renal Failure
by Shirley Russman, D.V.M.
Our protocol for treating chronic renal
failure includes a special diet, adequate hydration, potassium
supplementation, stomach acid control and calcitriol therapy to
control phosphorus levels. Calcitriol (a vitamin D3 metabolite)
may also be used to prevent or reverse secondary hyperparathyroidism
in dogs and cats with chronic renal failure.
Calcitriol is dosed in nanograms. Commercially available
products are for humans, and the dose is much too high for dogs or
cats (for example, the capsule contains 250 nanograms or 0.25 micrograms).
Our compounding pharmacist has been able to prepare any capsule (8
nanograms and up) or liquid (i.e. 4 nanograms/0.25ml) necessary to
meet our needs. We have used this compounded remedy over one
hundred times and have found it to be very successful in lowering
phosphorus levels in our patients with chronic renal failure. Serum
calcium levels should be monitored as hypercalcemia is a possible
consequence of calcitriol administration.
Calcitriol “has a rapid onset of action (1-4
days) and a short half-life (4-6 hours). Oral calcitriol is administered
to patients after initial stabilization with fluid therapy, dietary
protein and phosphorus restriction, the use of intestinal phosphate
binders and H-2 blockers as needed. Serum phosphorus should be
less than 6 mg/dL (1.9 mmol/liter) before initiating calcitriol.
“Hypercalcemia usually only occurs if calcitriol
is used in conjunction with intestinal phosphate binders, especially
calcium carbonate... Long-term use of phenytoin and the barbiturates
may interfere with the action of the drug, necessitating higher
doses of calcitriol... Thiazide diuretics may enhance the effects
of calcitriol predisposing to hypercalcemia. Calcitriol-induced
hypercalcemia may antagonize the antiarrhythmic effects of calcium
Handbook of Veterinary Drugs, 2nd edition, pp. 105-106