equine asthma treatment and drugs

Question 1

what are the general principles for tretment of both types of asthma?

Answer 1

Horses with mEA and sEA
* glucocorticoids
* bronchodilators

For mEA also:
* Immune modulation (Interpheron-alpha)
* Omega-3 supplementation

Other drug types/classes (i.e.: cromoglicate, N,butylscopolamine)
The type & duration of therapy will vary according to clinical presentation

Question 2

what is the most effective treament for sEA?

Answer 2

IV and Oral (powder given to fasted horses) dexamethasone
◦ Effects on lung function 2 & 6h post-admin. respectively
◦ Pharmacologic effect 24h
important for rescue therapy

Question 3

why is isoflupredone and oral prednisolone not used to treat sEA?

Answer 3

• Isoflupredone – very effective but hypokalemia in horses!
• Oral Prednisone - poor bioavailability in horses!)

Question 4

what is the treatment for acute sEA?

Answer 4

• IV dexamethasone: 0.04-0.1 mg/kg SID
• Followed by PO Dex 0.05 mg/kg or prednisolone 1 mg/kg SID
• Until respiratory effort & nasal discharge resolve
• Then follow with Inhaled GC
  ◦ Beclomethasone dipropionate 3750 ug BID
  ◦ Fluticasone 2000 ug BID (preferred)

Question 5

what inhailed glucocorticoids can be used for equine asthma?

Answer 5

◦ Beclomethasone dipropionate
◦ Fluticasone - (preferred)

Question 6

what drug is very effective for equine asthma and does not have the side effects of of glucocorticoids? what is the dose?

Answer 6

Ciclesonide
* Pro-drug
* Does not affect cortisol levels
* Dose:
◦ 8 activations BID x 5d then 12 activations SID for 5-10 days

Question 7

what is the treatment protocol for mEA?

Answer 7

Corticosteroids:
* Start PO Dex. 0.05 mg/kg or prednisolone 1 mg/kg SID (4 weeks)
* Followed by inhaled GC
◦ Beclomethasone dipropionate 500-1500 ug BID
◦ Fluticasone 2000 ug BID initially
‣ Tapered over 4 weeks to a minimum does of 1000 ug q 48hs

Question 8

what bronchodilators can be used along side glucocorticoids for equine asthma?
how are these administed?

Answer 8

• Beta-adrenergic (clembuterol, albuterol, salbutamol)
  ◦ Systemic should only be used in sEA & SPAOPD (mEA inhaled only )
• Parasympatholytics (ipratropium)

Clembuterol PO or IV
Inhailed:
◦ Salmeterol
◦ Albuterol
◦ Ipratropium bromide

Question 9

what other drug can be added on for the treatmwent of mEA? what are thought to be the benefits of this?

Answer 9

Interferon-alpha
◦ 50-150 Units/horse/day
◦ increases response to treatment - cure rates
◦ Decreased relapse rate
◦ Practical experience mixed

Question 10

what additiaonal drug can be added on for the treatment of mEA and sEA?

Answer 10

• Omega-3 fatty acids

Question 11

what additional treamtment can be given with mast-cell nediated mEA?

Answer 11

• Cromoglicate

Question 12

what are the adverse effects of glucocorticoids used for treatemtn of asthma?

Answer 12

• Adrenal suppression
  ◦ fluticasone - less effect than other steroids,
  ◦ ciclesonide - minimal effect
• Adrenal gland atrophy
• Immune suppression
• Laminitis

Question 13

what are the adverse effects of ystemic beta-adrenergic bronchodilators?

Answer 13

• Cardiovascular remodeling
• Tachyphilaxis

Question 14

what are the regulatory considerations for the treatement of equine asthma?

Answer 14

• Each drug and delivery method has a detection time
  ◦ The treatment should be discontinued before that time
• Times may vary according to pathology and other factors
• Detection times should be rechecked regularly