| Efficacy
of oral supplementation with L-lysine in cats
latently infected with feline herpesvirus
Maggs et al. of the College
of Veterinary Medicine, University of Missouri
examined the effects of orally administered L-lysine
on clinical signs of feline herpesvirus type 1
(FHV-1) infection and ocular shedding of FHV-1
in latently infected cats. Fewer cats and eyes
were affected by conjunctivitis, and onset of
clinical signs of infection was delayed on average
by 7 days in cats receiving L-lysine 400 mg once
daily for 30 days, compared with cats in the control
group. Significantly fewer viral shedding episodes
were identified in the treatment group cats, compared
with the control group cats. This dose caused
a significant but short-term increase in plasma
L-lysine concentration without altering plasma
arginine concentration or inducing adverse clinical
effects.
Am J Vet Res 2003 Jan;64(1):37-42
Click here to access the PubMed abstract of this article.
Dextromethorphan
Of the seven major human cough suppressants,
only dextromethorphanis indicated
for treating cough in small animals. If after
reviewing the indications and contraindications,
cough suppression is desired, the available human
products must be screened carefully as a very
limited number contain dextromethorphan without
other potentially harmful ingredients. Typically,
the dose in dogs and cats is 1 to 2 mg/kg three
to four times daily. Human products are not flavored
to an animal’s taste, and may require administering
a significant volume (typical strength is 15 mg/5
ml) to adequately dose an average size dog.
Stool Softeners
Docusate (DSS) can be used to assist in
the passage of hard or dry feces that may occur
secondary to dehydration or use of opioid analgesics
or metoclopramide. While capsules hide the bitter
taste, they can not be divided for appropriate
dosing in smaller animals. The recommended dose
in dogs and cats is 2 mg/kg once daily. For more
severe cases, appropriately dosed DSS enemas may
offer an alternative to phosphate-solution enemas.
Merck Veterinary Manual, 8th Edition,
pp. 1691
Ursodiol for Gallstones
The purpose of this study,
reported in Am J Health-Syst Pharm (Vol.
52) was to prepare an oral dosage form of the
bile acid ursodiol (also known as ursodeoxycholic
acid) from commercially available capsules and
to determine the short-term stability of this
formulation. The formula used for this extemporaneous
compound was found to be stable for up to 35 days.
Ursodiol in a Dog with
Chronic Hepatitis
A dog with severe cholestasis secondary
to chronic hepatitis was treated with ursodeoxycholic
acid (ursodiol) orally. After 2 weeks of daily
treatment, the dog was more active and had an
improved appetite. Monthly serum biochemical determinations
and analysis of individual bile acid profiles
documented improvement in hepatobiliary tests
and a marked reduction in the concentrations of
potentially hepatotoxic endogenous bile acids.
These effects were maintained for approximately
6 months.
J Vet Intern Med 1997 May-Jun;11(3):195-7
Click here to access the PubMed abstract of this article.
Studies have found an extemporaneously
compounded ursodiol suspension to be stable for
up to 35 days refrigerated. This drug is well
absorbed orally and enters the liver directly
from the portal system, and is then secreted into
bile. Ursodiol should be administered orally as
the first-pass effect is vital for effectiveness.
Aminocaproic Acid for
Degenerative Myelopathy (DM) in Dogs
DM appears with relative
frequency only in the German Shepherd breed (GSD);
confirmation of the diagnosis is important in
other breeds before assuming that they have DM
of GSD. During the past two decades, R.M. Clemmons,
DVM, Ph.D., and other researchers at the University
of Florida have provided important new insights
into the pathoetiology of DM. Recently, they have
found that when combined with the history, neurologic
signs, CSF protein concentration and EMG, an elevated
CSF acetylcholinesterase level helps confirm the
diagnosis. It is increasingly clear that DM is
caused by an autoimmune disease attacking the
nervous systems of patients, leading to progressive
neural tissue damage. In many respects, DM is
similar to Multiple Sclerosis in human beings.
The Integrative Medical Approach
to Treatment of Degenerative Myelopathy involves
four basic approaches: 1) exercise, 2) dietary
supplementation, 3) medication, 4) other supportive
measures. Conventional medicine has little to
offer patients with DM. On the other hand, use
of exercise, certain vitamins and selected drugs
have delayed or prevented progression of DM in
many afflicted dogs.
Clemmons et al have found 2 medications
which appear to prevent progression or result
in clinical remission of DM in up to 80% of patients
- aminocaproic acid (EACA) and n-acetylcysteine
(NAC). They propose that circulating immune-complexes
lead to endothelial cell damage in the vessels
of the CNS. Subsequently, fibrin is deposited
in the perivascular spaces. When this degrades
(point of action of aminocaproic acid), inflammatory
cells are stimulated to migrate into the lesions.
The inflammatory cells release prostaglandins
and cytokines (point of action of vitamin E and
C) which lead to the activation of tissue enzymes
and the formation of oxygen free-radicals (point
of action of acetylcysteine) which, in turn, leads
to tissue damage.They recommend giving EACA as
a flavored solution, 500 mg orally every 8 hours.
A “source for EACA is to have a compounding
pharmacy make the solution from chemical grade
EACA.” The only side effects that
have been attributed to EACA have been occasional
gastrointestinal irritation. This has presented
a problem only in a few patients, typically those
with pre-existing GI problems. The only known
drug interaction is with high dose estrogen compounds.
N-Acetylcysteine is a potent anti-oxidant
which has powerful neuroprotective effects. Clemmons
et al give 75 mg/kg divided in 3 doses a day for
2 weeks; then, 3 doses every other day. The N-acetylcysteine
must be diluted to a 5% solution; otherwise, it
will cause stomach upset. “This new treatment
is expensive unless purchased through compounding
pharmacies.” NAC can produce vomiting (due
to the sodium content of the pharmaceutical product,
which requires high concentration of base to buffer)
and may increase the bleeding time. Giving fresh
ginger 30 minutes before NAC or administering
NAC with food (or on a full stomach) often reduces
this effect.
The chances of successful treatment are
improved if the therapy is begun early in the
course of DM rather than later. A response to
the drugs should be evident within the first 7-10
days.
Chlorpromazine for
Anti-Emesis
Chlorpromazine (Thorazine®)
is a phenothiazine and works at the emetic center,
the chemoreceptor trigger zone, and peripheral
receptors; it is this veterinarian’s “all
purpose anti-emetic of choice” for cats.1
Chlorpromazine may cause extrapyramidal symptoms
in cats when administered at high doses. The drug
may discolor urine pink or red-brown, cause mild
sedation, and may potentiate hypotension in dehydrated
patients. Phenothiazines should not be given within
one month of worming with an organophosphate agent.
The recommended oral doses in dogs and cats is
3.3 mg/kg PO one to four times daily. Due to extensive
first pass metabolism2, it may be necessary
to reduce the dose in animals with liver disease.
A liquid concentrate can be appropriately flavored
for dogs or cats.
1Todd R. Tams, DVM, Dip ACVIM in CA
VMA C/E Conf Procd, 2000
2Veterinary Drug Handbook
3rd edition, Donald C. Plumb, ed.; pp. 129-30
Managing Anorexia in Uremic
Dogs and Cats
H2-receptor antagonists
(cimetidine, ranitidine, and famotidine) can be
useful to reduce gastric acid secretion. Increased
gastrin concentrations in serum during chronic
renal failure may stimulate excessive secretion
of gastric acid and cause ulcer formation. Some
uremic dogs and cats dramatically increase their
interest in food and food intake after therapy
with an H2 blocker. According to a presentation
at the Atlantic Coast Veterinary Conference by
Dennis J. Chew, DVM, Dip and C.A. Buffington,
DVM, some uremic animals may need this medication
for an extended period of time (months to rest
of their lives). Much of the experience of these
veterinarians has been either with cimetidine
at an initial dose of 10 mg/kg, followed by 5
mg/kg PO BID or famotidine at 1 mg/kg daily.
The Capsule Report, Vol. 19, No. 10,
Jan. 2001
Doxycycline for Prophylaxis
and Treatment of Osteoarthritis in Dogs
Prophylactic administration of doxycycline
(a tetracycline) has markedly reduced the severity
of canine osteoarthritis (OA) in weight-bearing
regions of the medial femoral condyle, and therapeutic
administration of oral doxycycline has been shown
to reduce the severity of articular cartilage
breakdown in various animal models of OA. This
disease modifying effect is associated with reductions
in the levels of active and total collagenase
and gelatinase in articular cartilage of the involved
joint.
A prospective, clinical study of
eighty-one dogs with OA secondary to spontaneous
cranial cruciate ligament (CCL) rupture concluded
that doxycycline inhibits nitric oxide production
in cartilage in dogs with CCL rupture, and that
doxycycline may have a role in the treatment of
canine OA. Dogs with OA secondary to CCL rupture
were divided into 2 groups before surgery. The
Doxy-CCL group (n = 35) received 3 to 4 mg/kg
doxycycline orally every 24 hours for 7 to 10
days. The CCL group (n = 46) received no treatment.
Synovial fluid, articular cartilage, synovial
membrane, and CCL samples were collected during
surgery or immediately after euthanasia from healthy
dogs (control group). Total nitric oxide concentrations
measured in cartilage were significantly lower
in the Doxy-CCL group than in the CCL group, but
were not different from those measured in the
control group.
In another study, ten healthy adult
mongrel dogs underwent transection of the left
anterior cruciate ligament, which resulted in
a marked decrease in bone mass, with increased
osteoclastic activity and increased bone formation.
Doxycycline treatment did not significantly affect
either bone formation or bone resorption. The
authors concluded that doxycycline protects against
joint breakdown in this OA model via inhibition
of matrix metalloproteinases in articular cartilage,
rather than through an effect on subchondral bone.
Vet Surg 2001 Mar-Apr;30(2):132-9
Click here to access the PubMed abstract of this article.
J Rheumatol 1996 Jan;23(1):137-42
Click here to access the PubMed abstract of this article.
J Rheumatol Suppl 1995 Feb;43:149-51
Click here to access the PubMed abstract of this article.
Vet Clin North Am Small Anim Pract 1997
Jul;27(4):863-81
Arthritis Rheum 1992 Oct;35(10):1150-9
Click here to access the PubMed abstract of this article.
Cisapride: a Prokinetic
Drug
Cisapride (Propulsid® - Janssen Pharmaceutica),
was removed from the U.S. and Canadian markets
by its manufacturer because of serious cardiac
effects in humans. However, cisapride
is now available as a bulk chemical for veterinary
use only and can be compounded as per your prescription
order.
Cisapride is chemically related to metoclopramide,
but unlike metoclopramide, it does not cross the
blood-brain barrier or have antidopaminergic effects
or cause extrapyramidal reactions. Cisapride “is
more potent and has broader prokinetic activity
than metoclopramide, increasing the motility of
the colon, esophagus (in cats and guinea pigs),
stomach, and small intestine... [Cisapride] has
been used in managing gastric stasis, idiopathic
constipation, gastroesophageal reflux, and postoperative
ileus in dogs and cats. Practitioners found cisapride
especially useful in managing chronic constipation
in cats with megacolon; in many cases, it alleviated
or delayed the need for subtotal colectomy. Cisapride
was also used in managing cats with hairball problems.”
“Cisapride appeared to be
well tolerated by dogs and cats. Adverse reactions
to cisapride have not been reported to the United
States Pharmacopeia’s Veterinary Practitioners’
Reporting Program... Disorders of GI motility
are common and frustrating clinical problems in
dogs and cats. Cisapride, with its extensive prokinetic
action, was a welcome addition to veterinary medicine.”
“Life after cisapride: Prokinetic drugs
for small animals.” Patricia M. Dowling,
DVM, MS, DACVIM, DACVCP Veterinary
Medicine, September 2000, pp. 678-685
Doses:
Dogs -
As a promotility agent: initially 0.5mg/kg three
times daily
To reduce regurgitation associated with megaesophagus:
0.55mg/kg
orally one to three times daily, no less
than 30 minutes before feeding.
As an antiemetic: 0.1-0.5mg/kg orally every 8
hours.
Cats -
For chronic constipation: initially, 2.5mg (for
cats up to 10#) or 5mg
(cats 11-15#), or up to 7.5mg (for
cats over 16#) three times daily, 30
minutes before food, in combination
with stool softener and bulk agent.
Cisapride is contraindicated in patients
in whom increased GI motility could be harmful
(e.g., perforation, obstruction, GI hemorrhage).
Absorption of other orally-administered drugs
may be affected. Cisapride may enhance anticoagulants’
effects; additional monitoring and anticoagulant
dosage adjustments may be required. Cisapride
may enhance the sedative effects of benzodiazepines.
Clients should be advised to monitor the animal
and report any adverse effects.
Veterinary Drug Handbook, 3rd edition,
Donald C. Plumb, editor. pp. 139-140
Hairball Remedy
Cat and ferret owners
continually search for specialized foods and treats
that their pets will readily consume and will
also be effective for hairball prevention or elimination.
Call us for a customized, flavored
hairball remedy for your patients!
Stanozolol
In a study conducted at
the Animal Health Unit and Gastrointestinal Sciences,
University of Calgary, Alberta, ten healthy, intact,
adult male sled dogs received either stanozolol
tablets, 2 mg/dog PO, q12h, for 25 days or an
intramuscular injection of stanozolol 25 mg on
Days 7, 14, 21, and 28. A 15N amino acid (5.27
mmol) was infused intravenously into each dog
on Day 0 (before stanozolol treatment) and on
Day 31 (after stanozolol treatment). Both oral
and injectable stanozolol resulted in significant
increases in amino acid nitrogen retention compared
to pretreatment values. Oral stanozolol increased
nitrogen retention from 29.2 +/-8.2% to 50.3 +/-
9.2%, while stanozolol injection increased nitrogen
retention from 26.6 +/- 9.9% to 67.0 +/- 7.5%.
The nitrogen retention action of stanozolol may
be beneficial in dogs under stress of surgical
trauma and chronic disease.
In a separate blinded crossover
trial at the College of Veterinary Medicine, Kansas
State University, 22 castrated Beagles with experimentally
induced chronic renal failure were treated with
stanozolol. Cowan et al. concluded that
for dogs with mild-to-moderate, nonuremic, experimentally
induced, chronic renal failure, stanozolol had
positive effects on nitrogen balance and lean
body mass. Stanozolol did not have a significant
effect on body fat, bone mineral content, or food
consumption per kilogram of body weight.
Anabolic steroids such as stanozolol
have been used to treat geriatric dogs. These
drugs can increase nitrogen and mineral retention
so that the body can better utilize dietary protein.
As a result, the dog’s appetite may improve,
resulting in more strength, energy, and weight
gain. There is one reported case of the use of
stanozolol (0.5 mg/kg, SQ, BID, PRN) to stimulate
appetite in a rabbit. However, this class of drugs
is not without potentially serious side-effects
which must be considered before using them. Anabolic
steroids should be used with caution in animals
with heart, liver, or kidney problems, or in animals
with breast or prostate cancer. Stanozolol should
not be used in pregnant animals, during lactation,
in young animals, or in male breeding animals.
Anabolic steroids may increase the effects of
warfarin and other anticoagulants.
In dogs, reported side effects are
mainly androgenic, including increased aggression,
increased activity, weight gain and mood alterations.
However, in cats with and without chronic renal
failure, there are reported cases of hepatotoxicity
that appear to be related to the use of stanozolol.
J Am Vet Med Assoc. 1997 Sep 15;211(6):719-22
Click here to access the PubMed abstract of this article.
Can J Vet Res. 2000 Oct;64(4):246-8
Click here to access the PubMed abstract of this article.
Veterinary Forum. April 1999
Click here to access the PubMed abstract of this article. |
