Last October the FDA approved a nasal spray (Tyrvaya™) to treat the signs and symptoms of dry eye disease. The nasal spray contains a varenicline solution that binds to receptors in the nasal mucosa and activates the trigeminal nerve which in turn promotes tear production.
Varenicline taken orally is used to help stop smoking. It is a type of agonist which means that it is a drug that binds to a receptor and produces the same action as the natural substance that normally binds to the receptor.
Research shows that the parasympathetic nervous system (PNS) controls tear film production and the PNS can most easily be accessed through the nose where it can trigger basal tear production. So using a drug that is an agonist in the nose made sense as a way to get the drug where it would activate tear production.
What are Basal Tears?
Basal tears are the complex three-layer tears that coat the eye, supply nutrients, and protect the eye from drying out. The eyes are constantly producing and shedding basal tears. When there is dust in the air or debris in your eye, the tears that are produced to clear these away are basal tears.
Basal tears have a mucus component that makes them spread evenly across the surface of the eye and that mucus contains antibodies and proteins for resistance to infection.
Basal tears differ from emotional and reflex tears. Emotional tears are the ones your eyes produce when you cry, and they are more watery than basal tears. They also contain stress hormones and natural pain killers.
Reflex tears are produced in reaction to a stimulus and are mostly water. The stimuli that triggers them ranges from cold wind to the acid from fresh cut onions or chilies. Reflex tears can also come from muscle tension on the tear glands and can happen when coughing, vomiting, or yawning.
Dry Eye Disease
Dry eye disease causes blurred vision, glare, and eye fatigue. If not treated, dry eye disease can cause lasting damage to the corneal surface, eye inflammation, corneal ulcers and vision loss.
- Symptoms of dry eye disease include:
- Stinging, burning, or scratchy sensation in the eyes
- Stringy mucus in or around the eye
- Light sensitivity
- Eye redness
- Watery eyes—triggered by the response to the irritation of dry eyes
- Blurred vision
- Eye fatigue
- A sensation of having something in the eye
Availability of the Nasal Spray
Currently there is only one dry eye nasal spray and it is available by prescription only. It is produced by Oyster Point Pharma—a biopharmaceutical company based in Princeton, New Jersey that focuses on the development of pharmaceutical therapies to treat ophthalmic diseases.
The nasal spray is Tyrvaya™ and is used twice a day per nostril to activate tear film production. In two 28-day clinical trials, Tyrvaya increased the amount of basal tear film produced on average after 4 weeks of use, when used twice a day 12-hours apart.
The most common side effects were sneezing in 82% of the clinical trial participants, coughing in 16%, throat irritation in 13%; and nose irritation in 8%.