***Please Note:

None of these suggestions are specific recommendations for your horse; we have compiled a list of medications which some clients have used successfully for horses with headshaking under the direction of their veterinarian. All medications have potential side effects. Always consult directly with your veterinarian before giving any medications to your horse. The information below may not be copied or distributed and is for your consideration only to discuss with your veterinarian.

If you wish to support our headshaking research please consider a donation by making a check to ‘Regents of the UC’ and send to Dr. Madigan, Dept of Medicine and Epidemiology, Tupper Hall, School of Veterinary Medicine, University of California, Davis, Ca 95616.  Enclose a note saying that the donation is 'for support of Dr. John Madigan's research.’ These are considered tax deductible donations. Our aim is to determine the exact cause and a specific cure for this condition.

Veterinary Prescribed Drugs

Note: all of these drugs may "test" in competition horses.  These drugs do not correct the cause of headshaking, they are used as an aid to controlling the nerve pain associated with headshaking.

Drugs to Control Neuropathic Pain 


  • 0.3 mg/kg twice daily, orally
  • Keep in mind that this drug will test in show horses
  • In one study, 43 out of 61 horses responded to this treatment (70%)
  • 56% of the horses that improved showed moderate to great improvement

Madigan, JE and Bell, S A Owner survey of headshaking in horses. Journal of the American Veterinary Medical Association 2003; 219: 334-357.

Adverse effects seen with the use of Cyproheptadine include;

  • Sedation
  • Dryness of the mucous membranes
  • Mild depression, inappetance or lethargy
  • Colic

Symptoms associated with overdose may include;

  • Central nervous system depression or stimulation (this may include seizure)
  • Severe drying of the mucous membranes
  • Increase in heart rate
  • Urine retention
  • Fever


  • 1 to 4 gms per horse orally either twice daily or 4 times daily
  • May be used alone or in combination with the cyproheptidine treatment listed above

Potential adverse reactions should be discussed with your veterinarian  and can include all of the adverse effects listed for cyproheptidine above.

Atarax (Hydroxyzine)

  • 400 mg per 1000 pound horse administered twice daily orally

Adverse effects seen with Atarax may include;

  • Hyperexcitability
  • Tremors
  • Depression
  • Behavioral changes


  • 2 cc reposital IM per horse
  • Repeat as needed every one to four months
  • Use only unopened vials or, if opened, use refrigerated drug which has no discoloration
  • In one study, 11 of 15 horses responded to this treatment, the other four horses showed no improvement at all

Side effects/possible risks associated with Fluphenazine use;
Twelve hours after administration you may see:

  • Agitation and restlessness
  • Pawing 
  • Frantic behavior
  • Sweating

The side effects listed above, although rare, can be VERY SEVERE/DRAMATIC and can be DANGEROUS to you and your horse. This requires immediate veterinary attention.

Phenobarbital (anti-convulsant)

  • 97.2 mg/tablet- give 16 tablets orally twice daily to a 1000 pound horse

Adverse effects may include;

  • Lethargy
  • Anxiety or agitation
  • Increased drinking
  • Increase in urination
  • Excessive desire to eat

Combination Therapy

  • Cyproheptidine standard dose
  • Melatonin standard dose
  • Spirulina wafers orally – Spirulina is another supplement that may help decrease stimulation of the trigeminal nerve. You can find Spirulina wafers online from Springtime Inc (http://www.springtimeinc.com). Please dose according to the label on the bottle. 

Therapies Not as Promising as Once Thought

Equity Vaccine (New Zealand)

  • The Equity vaccine was the focus of a joint study conducted by veterinarians from UC Davis and Massey University  published in December of 2010.  In this study conducted by K. J. Pickles, J. Berger, R. Davies, J. Roser and J. E. Madigan, 19 horses in New Zealand and the United States received two doses of the Equity vaccine, a GnRH (a hormone) vaccine.  The study found that "although some of the owners perceived a subjective improvement in their horses’ headshaking behavior, repeated owner evaluation scoring did not demonstrate a beneficial effect of GnRH vaccination."
  • Based on this study we cannot recommend the use of this vaccine at this time.
There are four basic categories of treatment available to your horse.  

These four categories are; 

1. Physical treatments

2. Dietary treatments

3. Drug treatments

4. Combination therapy

Physical and dietary adjustments are the easiest to make, so we will discuss these first. We recommend including your veterinarian in the decision making process when making a change to your horse's diet or supplement regimen.

Physical Methods

These methods are the easiest to try and you can use them in combination with any of the other treatments (dietary and drug).  We highly recommend trying these individually and in combination, as each horse will respond differently.
The drug therapies listed below may not be appropriate for your horse.  All drug therapies have potential side effects. In order to ensure the safety and wellbeing of your horse, it is very important that any drug treatment be discussed with, prescribed, and monitored by your veterinarian.  These are not recommendations, they are simply a list of drugs that veterinarians have prescribed to treat headshakers.
If light is a trigger;

  • Some owners keep these horses indoors during the day
  • Consider having the horse wear a UV blocking sun shade fly mask from Guardian Mask in San Diego. http://www.horsemask.com
  • Try a tinted polo eye guard

If exercise is a trigger (50% of headshakers only exhibit symptoms during exercise);

  • Use a nose net or other device which attaches to or dangles over the nostril and muzzle area 
  • The German dangling device has been succesfully used on several horses (very effective when you are in the 30% group mentioned below!) 
  • Ear covering and forehead 'dangling' material

Nose net effectiveness

  • Thirty-six owners of seasonally headshaking horses took part in a trial to compare the effectiveness of three types of nose net, a traditional cylindrical net (full net) and two forms of larger mesh nets which cover only the nostrils and the top half of the muzzle (half nets)
  • Approximately 75% of owners reported some overall improvement with each net
  • Around 60% of owners reported a 50% or greater improvement
  • 30% of owners reported a 70% or greater improvement

Mills, D. S., Taylor, K. Field Study of the efficacy of three types of nose net for the treatment of headshaking in horses. Veterinary Record 2003;152:41-44.

Chiropractic treatment

  • In one study, one in 28 headshaking horses responded to chiropractic treatment.  

Madigan, JE and Bell, SA. Owner survey of headshaking in horses. Journal of the American Veterinary Medical Association 2001; 219: 334-357.


  • In one study, four in 25 headshaking horses responded to acupuncture treatment.

Madigan, JE and Bell, SA. Owner survey of headshaking in horses. Journal of the American Veterinary Medical Association 2001; 219: 334-357.
Dietary Adjustments

Weight Loss 

  • Allow mild weight loss and continue exercise.  In the past a low protein diet may have been recommended, we no longer recommend lower protein intake, only mild weight loss.
  • This treatment will take considerable time to show improvement.  
  • Maintaining a healthy weight for your horse is of particular importance if it is a headshaker, as overweight horses are over-represented.

Dietary Supplements

Melatonin: this treatment tricks your horse's body into thinking it is a different time of year (alteration in photoperiod) and is useful for some seasonal headshakers). 

Administering melatonin therapy;

  • This resets the horse's internal seasonal clock (biorhythm) by switching their photoperiod back to winter
  • This treatment is most effective with headshaking that starts in the spring.
  • 12 mg-18 mg melatonin orally starting Nov 1st  given every day at 5:00 PM. Give 15 mg (average size horse) - 18 mg (larger horse) of melatonin orally (five -six 3 mg tablets) every day at 5:00 PM. It is important that the tablets are given at 5:00 PM to correlate with the naturally occurring rise of melatonin with onset of darkness at 5:00PM in the wintertime.
  • You can try starting melatonin therapy in mid-season, but the treatment is not as effective
  • For best results give this dose at 5:00 PM all year roundIt is very difficult to manipulate the photoperiod, and administering the dose year round will increase the likelihood that this treatment is effective. 
  • Horses on melatonin therapy may not shed their winter coat.  These horses may need body clipping. 

Magnesium: magnesium is an electrolyte critically involved in nerve function.  Supplementing the diet with magnesium may help decrease the stimulation of (quiet) the trigeminal nerve.

One commercial formulation of magnesium is Quiessence. Quiessence contains 5g of magnesium in every ounce

  • Feed  2 ounces of Quiessence (10 grams of magnesium oxide) once a day to a 1000 pound horse
  • If no improvement is seen in two weeks, increase to 4 ounces (20 grams magnesium oxide) once a day
  • Monitor magnesium levels as directed below 

Another form of magnesium that may be more bio-available is MagRestore
  • This product is available as a powder and is measured in 10 gram servings.  Start treatment with 2 servings a day.  If no improvement is seen in 2 weeks, increase treatment to 4 servings per day.  
  • Monitor magnesium blood levels as directed below

IMPORTANTIf you are supplementing your horse's magnesium, have your veterinarian monitor the ionized and total magnesium level in your horse's blood.  A measurement should be taken about 2 weeks after starting treatment and checked once monthly after that to make sure it is not too high.  Symptoms of magnesium overdose include:

  • Drowsiness
  • Central nervous system depression (a drop in function of the central nervous system)
  • Muscle weakness
  • Slowing of the heart rate or fast, irregular rhythm
  • Slowing/reduced function of the respiratory system
  • Low calcium in the blood
  • If levels remain too high for too long, cardiac arrest and death will occur

New Treatment

Top Stock Headshaking Formula from New Zealand

When Dr Madigan was on sabbatical in NZ in 2005 he continued to work with horses with headshaking there. He met many horse owners struggling with headshaking horses. Over the past two years several NZ horse owners told him their horses headshaking improved when given Top Stock Heasdshaking Formula.  We have completed a  small owner evaluated clinical trial (without controls) and found that 7 of 10 horses with headshaking improved to some degree while receiving this product. Improvement usually started within a 1 week time frame. Further studies are necessary and ongoing but at this time this preliminary owner observational data is encouraging.

  • Follow manufacturer directions (we have found that most horses needed to continue with the higher initial dosing)