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Insto eye drops can help provide relief from minor eye irritations, such as red, itchy, swollen, watery, and dry eyes. There are two types of Insto products with different benefits. The active ingredients contained in this product are tetrahydrozoline HCl and hydroxypropyl methylcellulose which can help relieve eye irritation.

Products of Insto

Insto is available in two variants with different benefits. 

1. Insto Regular

Insto Regular can be used to treat red eyes. It contains active ingredients that can relieve minor eye irritations, such as red, itchy, sore, and watery eyes.

This Insto variant comes in two sizes, 7.5 ml and 15 ml bottle sizes. This product contains tetrahydrozoline HCl.

2. Insto Dry Eyes

Insto Dry Eyes variant is designed to work like real tears to moisturize your eyes. It contains active ingredients that can treat and lubricate dry eyes. 

This variant is available in 7.5 ml-sized bottles. This product contains hydroxypropyl methylcellulose.

Insto Dosage Considerations 

Do not change the dose without your doctor’s approval. Here is the recommended dosage considerations for Insto:

  • Recommended dosage for Insto Regular: Apply 2-3 drops per use, 3 to 4 times a day or as recommended by your doctor.
  • Recommended dosage for Insto Dry Eyes: Apply 1-2 drops each time, 3 times a day or as recommended by your doctor.

General Guidelines

Use Insto as exactly directed by your doctor or read the instructions on the product package. Here’s how to use insto:

  • Read and follow all directions listed on the product package or use the medicine as directed by your doctor. If you have any questions, do not hesitate to ask your doctor or pharmacist.
  • Before using eye drops, wash your hands first. To avoid contamination, do not touch the tip of the dropper nor let it touch your eye or other surfaces. Remove your contact lenses before using eye drops. Wait at least 10 minutes after applying the eye drops before putting on contact lenses.
  • Before using Insto, check the liquid first. Do not use it if the liquid changes color or becomes cloudy. Keep the medicine out of reach of children and pets.
  • Apply Insto on the affected eye four times a day as needed or as directed by your doctor.
  • Tilt your head back, look up, and pull down your lower eyelid. Hold the dropper just above the eye and squeeze out a drop into your eye. Look down and gently close your eyes for 1 to 2 minutes. Place one finger on the corner of your eye and apply gentle pressure. This will prevent the medicine from draining into your nose. Try not to blink and do not rub your eyes. Repeat the same steps if you require several drops.
  • Be sure to close the dropper tightly after use. If you are using other types of eye medications–wait at least five minutes. Put the eye drops first before using the ointment.
  • Excessive use can worsen red eyes. Tell your doctor if this happens. Do not use this medication for more than 3 to 4 days at a time.
  • If your condition persists or worsens after 72 hours, or if you think you have a serious medical problem, you should stop using this product and seek medical help promptly.

What is Insto Used for

Products of insto eye drops can be used to relieve red eyes and dry eyes by creating artificial tears.

Contraindications for Insto

This product has contraindications due to the Tetrahydrozoline. Insto is contraindicated with:

  • Allergic to Murine Tears Plus Drop
  • Use of monoamine oxidase (MAO) in the last 14 days


Before using Insto eye drops, pay attention to the following precautions: 

  • Tell your doctor or pharmacist if you are allergic to any ingredients contained in the product; or if you have any other allergies. This product may contain inactive ingredients which can cause allergic reactions or other problems.
  • Tell your doctor or pharmacist about your medical history, especially if you have glaucoma, heart disease (for example, heart attack and chest pain), high blood pressure, diabetes, eye infection, eye injury, or hyperthyroidism. 
  • This medicine may cause temporary blurred vision. You should not drive, use machinery, or do any activity that requires clear vision until you are sure you can perform such activities safely.
  • Be careful when using this product with children, as children may be more sensitive to the effects of the product, such as eye irritation.
  • During pregnancy, this medicine should only be used when clearly needed. Discuss the risks and benefits with your obstetrician.
  • It is unknown if this medicine passes into breast milk. You are recommended that you consult an obstetrician or a lactation consultant before breastfeeding.

Consult your pharmacist or doctor for more information regarding the precautions before using Insto or other eye medications.

Drug Interactions

If you use this product as directed by your doctor or pharmacist, they may already be aware of possible drug interactions. Do not start, stop, or change the dose of any medicine before consulting your doctor or pharmacist first.

Before applying this product, tell your doctor or pharmacist of all prescription and nonprescription or herbal products you are currently taking,  especially if you are taking guanethidine, tricyclic antidepressants (for example, amitriptyline), and monoamine oxidase (MAO), such as:

  • Linezolid
  • Methylene blue
  • Moclobemide
  • Phenelzine
  • Procarbazine
  • Rasagiline
  • Safinamide
  • Selegiline
  • Isocarboxazid
  • Tranylcypromine 

Tetrahydrozoline may increase the possibility to suffer serious side effects when used with: 

  • Ergonovine
  • Ergotamine
  • Iobenguane
  • Methylergonovine
  • Dihydroergotamine
  • Methysergide maleate

Insto also contains hydroxypropyl methylcellulose–which should not be used when eating certain types of food as drug interactions may occur. Consumption of alcohol or tobacco with certain drugs can also cause interactions.

Before using this product, tell your doctor or pharmacist about any current medications you are taking.

List of Insto Side Effects

Below are some of the most common side effects of Insto:

  • Eye pain, red eyes, dilated pupils, or blurred vision. If any of these side effects persist or worsen, tell your doctor or pharmacist immediately.
  • If your doctor has prescribed you this medicine, he or she has assessed that the benefits outweigh the risk of side effects. Most people using this medicine do not have serious side effects.
  • Tell your doctor right away if any of the unusual side effects occur, such as shaking (tremors), rapid and irregular heartbeat, palpitations, headaches, sweating, weakness, and anxiety. 
  • Stop using this medication and tell your doctor right away if you have any of the side effects such as eye pain, red eyes, itchy eyes, swelling in or around the eyes, or other vision problems.
  • Serious allergic reactions to this drug are rare. However, seek immediate medical help if you notice any symptoms of a serious allergic reaction, such as rash, itching, swelling (particularly in your face, tongue, or throat), dizziness, and difficulty breathing.
  • If you notice other effects not listed above, contact your doctor or pharmacist right away. 

Book an appointment with your doctor or pharmacist via Smarter Health to find out more about the recommended dosage for Insto eye drops and its proper use based on your condition. Smarter Health allows you to access healthcare services and facilities whenever you need them. Contact Smarter Health now.

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