Timosan: Uses, Dosage & Side Effects

What Is Timosan and What Is It Used For?

Timosan contains the active substance timolol maleate, which belongs to a pharmacological class known as non-selective beta-adrenergic receptor blocking agents (beta-blockers). When applied topically to the eye, timolol reduces intraocular pressure (IOP) by decreasing the rate at which aqueous humor—the clear fluid that fills the anterior chamber of the eye—is produced by the ciliary body. Elevated IOP is the primary modifiable risk factor for glaucoma, a group of progressive optic neuropathies that can lead to irreversible blindness if left untreated.

Timolol was first approved for ophthalmic use in 1978 and quickly became the gold standard for medical glaucoma therapy. It remains one of the most extensively studied and widely prescribed IOP-lowering agents worldwide. The World Health Organization (WHO) includes timolol on its Model List of Essential Medicines, recognizing it as one of the most efficacious, safe, and cost-effective medicines needed in a health system. Timosan is manufactured by Santen Oy, a pharmaceutical company specializing in ophthalmic products.

The drug works through a well-characterized mechanism. By blocking beta-1 and beta-2 adrenergic receptors on the ciliary epithelium, timolol reduces the formation and secretion of aqueous humor. This typically produces a 20–35% reduction in IOP from baseline, with onset of action within approximately 30 minutes, peak effect at 1–2 hours, and a duration of approximately 24 hours. This pharmacokinetic profile allows for convenient once-daily dosing with the long-acting formulation.

Timosan is indicated for the treatment of two primary conditions:

• Chronic open-angle glaucoma — The most common form of glaucoma worldwide, affecting approximately 3.5% of people over 40 years of age. It is characterized by a gradual increase in intraocular pressure due to impaired drainage of aqueous humor through the trabecular meshwork, leading to progressive optic nerve damage and visual field loss. Open-angle glaucoma is often called the “silent thief of sight” because it typically causes no symptoms until significant irreversible damage has occurred.
• Ocular hypertension — A condition defined by an intraocular pressure consistently above 21 mmHg without detectable optic nerve damage or visual field loss. Although not all patients with ocular hypertension develop glaucoma, the condition represents a significant risk factor. The Ocular Hypertension Treatment Study (OHTS) demonstrated that reducing IOP in patients with ocular hypertension reduces the risk of developing glaucoma by approximately 50%.

Timosan may be prescribed as a first-line monotherapy or as part of a multi-drug regimen. According to the European Glaucoma Society (EGS) guidelines and the American Academy of Ophthalmology (AAO) Preferred Practice Patterns, the target IOP should be individualized based on the severity of glaucoma, the rate of disease progression, risk factors, and the patient’s life expectancy. While prostaglandin analogs have largely replaced beta-blockers as the most commonly prescribed first-line agents in some markets, timolol remains an excellent choice—particularly when cost is a consideration, when prostaglandins are not tolerated, or as adjunctive therapy in combination with other drug classes.

What Should You Know Before Using Timosan?

Before starting treatment with Timosan, it is essential to have a thorough discussion with your ophthalmologist or prescribing physician about your complete medical history, current medications, and any known allergies. Although timolol is applied topically to the eye, it can be absorbed into the bloodstream through the conjunctival vasculature and nasolacrimal duct, potentially causing systemic beta-blockade effects that affect the heart, lungs, and metabolic systems.

Contraindications

Warnings and Precautions

Talk to your doctor before using Timosan if you have or have previously had any of the following conditions, as they may require additional monitoring, dose adjustment, or consideration of an alternative therapy:

• Coronary artery disease — Symptoms such as chest pain, tightness in the chest, or shortness of breath. Timolol may reduce heart rate and cardiac output, which could exacerbate ischemic symptoms.
• Low blood pressure — Beta-blockers can cause further blood pressure reduction, particularly when combined with other antihypertensive medications.
• Heart rhythm disorders — Including slow heart rate or irregular heartbeat not severe enough to contraindicate use, but requiring monitoring.
• Respiratory problems or mild COPD — Even non-selective topical beta-blockers can cause bronchospasm in susceptible individuals. Patients with mild-to-moderate airways disease should be closely monitored.
• Peripheral circulatory disorders — Such as Raynaud’s disease or Raynaud’s syndrome. Beta-blockers can worsen peripheral vasoconstriction and reduce blood flow to the extremities.
• Diabetes mellitus — Timolol can mask the signs and symptoms of hypoglycemia (low blood sugar), particularly tachycardia, palpitations, and tremor. This is especially important for patients on insulin or oral hypoglycemic agents who may be at risk of hypoglycemic episodes.
• Overactive thyroid (hyperthyroidism) — Timolol can mask the cardiovascular signs of thyrotoxicosis, such as rapid heart rate. Abrupt withdrawal of beta-blockers may precipitate a thyroid storm.
• Atopy or history of severe allergic reactions (anaphylaxis) — Beta-blockers can increase the severity of anaphylactic reactions and reduce the effectiveness of epinephrine (adrenaline) used to treat them. This is a particularly important consideration for patients who carry epinephrine auto-injectors.
• Corneal disease — Beta-blockers may cause dry eyes. Patients with pre-existing corneal conditions should be monitored for signs of corneal deterioration.

Use in Children

Timosan is not recommended for children due to the lack of adequate clinical experience in pediatric populations. The systemic effects of topical beta-blockers can be proportionally greater in children due to their smaller body mass, and serious adverse events including bradycardia, hypotension, and apnea have been reported with ophthalmic timolol in neonates and young children. If a child requires IOP-lowering treatment, the pediatric ophthalmologist will select an appropriate alternative.

Pregnancy and Breastfeeding

If you are pregnant, think you may be pregnant, or are planning to become pregnant, consult your doctor before using Timosan. Beta-blockers, including timolol, may cause harmful effects on the fetus when absorbed systemically, including fetal bradycardia, hypotension, and hypoglycemia. Timosan should not be used during pregnancy unless your doctor determines that the potential benefit clearly outweighs the potential risk to the fetus.

Breastfeeding: Timolol is excreted in human breast milk. Timosan should not be used while breastfeeding, as beta-blockers may cause serious adverse effects in nursing infants, including bradycardia and respiratory depression. If treatment with Timosan is necessary, breastfeeding should be discontinued. Discuss alternative feeding options with your doctor and midwife.

Driving and Operating Machinery

Timosan may cause transient blurred vision immediately after instillation. If you experience blurred vision or other visual disturbances after applying the eye drops, do not drive or operate machinery until your vision has cleared. You are responsible for assessing whether you are fit to perform activities that require sharp eyesight, concentration, and alertness.

Important Information About Contact Lenses

Timosan contains benzalkonium chloride (0.05 mg/ml) as a preservative. This compound can be absorbed by soft contact lenses and may cause lens discoloration. You should remove contact lenses before applying Timosan and wait at least 30 minutes before reinserting them. Benzalkonium chloride may also irritate the eyes, especially if you have dry eye syndrome or corneal problems. If you experience irritation, stinging, or pain after using Timosan, contact your doctor promptly.

How Does Timosan Interact with Other Drugs?

Drug interactions with Timosan can occur because timolol, despite being applied topically to the eye, is absorbed into the systemic circulation through the conjunctival blood vessels and the nasolacrimal duct. Once absorbed, it can interact with other medications that affect the cardiovascular, respiratory, and metabolic systems. The degree of systemic absorption can be reduced by applying nasolacrimal occlusion (pressing the inner corner of the eye for 2 minutes after instillation).

Always inform your doctor or pharmacist about all medications you are currently taking, have recently taken, or plan to take. This includes prescription drugs, over-the-counter medications, herbal supplements, and other eye drops.

When using Timosan together with other eye drops, allow an interval of at least 10 minutes between instillation of each medication. This prevents the second drop from washing out the first before adequate absorption has occurred. Eye drops should generally be applied before eye ointments or gels, as thicker formulations can create a barrier to absorption of subsequent drops.

What Is the Correct Dosage of Timosan?

Always use Timosan exactly as your doctor has instructed. If you are unsure about any aspect of your treatment, consult your ophthalmologist or pharmacist. Consistent adherence to the prescribed dosing schedule is essential for maintaining stable IOP control and preventing glaucoma progression. Studies have shown that non-adherence to glaucoma medications is a significant risk factor for disease progression.

Adults

Children

Elderly Patients

How to Apply Timosan Eye Drops

Proper application technique is crucial for ensuring the medication reaches the eye effectively while minimizing systemic absorption and potential side effects. Follow these steps carefully:

1. Wash your hands thoroughly before handling the eye drop bottle.
2. Open the bottle carefully. Do not touch the tip of the dropper to any surface to avoid contamination.
3. Tilt your head back and look upward. You may sit, lie down, or stand in front of a mirror—choose the position that is most comfortable for you.
4. Gently pull down the lower eyelid to create a small pocket between the eyelid and the eye.
5. Hold the bottle upside down above the eye and squeeze gently to release one drop into the pocket formed by the lower eyelid.
6. Close your eye and press your finger gently against the inner corner of the eye (near the nose) for approximately 2 minutes. This technique (nasolacrimal occlusion) is critically important as it reduces the amount of timolol that enters the systemic circulation through the nasolacrimal duct, thereby minimizing cardiovascular and respiratory side effects.
7. If the drop misses the eye, try again with a new drop.
8. Replace and tighten the cap immediately after use. The eye drop bottle is for personal use only—do not share it with others.

Missed Dose

If you forget to apply your daily dose, use it as soon as you remember. However, if it is nearly time for your next scheduled dose, skip the missed dose and continue with your regular dosing routine. Do not apply a double dose to compensate for a forgotten one. If you frequently forget doses, consider setting a daily alarm or keeping the bottle next to something you use every morning (such as a toothbrush) as a reminder.

Overdose

Stopping Treatment

Do not stop using Timosan without first consulting your doctor. Abrupt discontinuation of beta-blocker therapy may lead to a rebound increase in intraocular pressure, and in patients with cardiovascular conditions, sudden withdrawal of systemic beta-blockade can precipitate angina, arrhythmias, or myocardial infarction. If your doctor decides to switch you to a different IOP-lowering medication, the transition will typically be managed gradually.

What Are the Side Effects of Timosan?

Like all medicines, Timosan can cause side effects, although not everybody gets them. Because timolol is a beta-blocker that can be absorbed into the bloodstream even when applied as eye drops, side effects can occur both in the eye (local effects) and throughout the body (systemic effects). The systemic side effects are similar to those seen with oral beta-blockers, although they occur less frequently with ophthalmic administration.

Eye-Related Side Effects

Systemic (Whole-Body) Side Effects

Like other ophthalmic beta-blockers, timolol is absorbed into the bloodstream. The systemic side effects listed below have been reported with beta-blocker eye drops as a class. The frequency of these effects is generally lower than with oral beta-blockers, but they can be clinically significant, particularly in patients with pre-existing cardiovascular or respiratory conditions.

If any side effect worsens or persists, or if you notice effects not listed above, contact your doctor or pharmacist. You can also help monitor drug safety by reporting suspected side effects to your national medicines regulatory authority.

How Should You Store Timosan?

Proper storage of Timosan is essential to maintain the medication’s potency, sterility, and effectiveness throughout its shelf life. Eye drops are particularly susceptible to microbial contamination and chemical degradation if not stored correctly, which could reduce their therapeutic effect or introduce infection risk to the eye.

• Temperature: Store at or below 25°C (77°F). Do not freeze.
• Light: Keep the bottle in its outer carton when not in use to protect from light, as timolol may be light-sensitive.
• Orientation: Store the bottle upside down for better dripping, as recommended by the manufacturer.
• Children: Store out of the sight and reach of children.
• After opening: Discard the bottle 4 weeks after first opening, even if there is solution remaining. The preservative cannot guarantee sterility indefinitely once the seal has been broken. Write the date of first opening on the bottle to help you track this.
• Expiry date: Do not use after the expiry date printed on the packaging. The expiry date refers to the last day of the stated month.
• Visual inspection: Do not use Timosan if you notice any signs of deterioration, such as discoloration, cloudiness, or particles in the solution.

Do not dispose of medicines via wastewater or household waste. Return unused or expired medication to a pharmacy for safe disposal. This helps protect the environment and prevents accidental exposure to others.

What Does Timosan Contain?

Understanding the composition of Timosan is important for identifying potential allergens and for understanding why certain precautions—such as contact lens removal—are necessary. The formulation has been designed to ensure drug stability, appropriate pH, and adequate retention on the ocular surface.

Physical appearance: Timosan is a clear solution supplied in a polyethylene dropper bottle fitted with a dropper tip and screw cap. It is available in pack sizes of 1 × 5 ml and 3 × 5 ml. Not all pack sizes may be marketed in all countries.

Manufacturer: Timosan is manufactured by Santen Oy, Kelloportinkatu 1, FI-33100 Tampere, Finland. The marketing authorization is held by Santen Oy, Niittyhaankatu 20, FI-33720 Tampere, Finland. Santen is a global pharmaceutical company specializing in ophthalmology, with products available in over 60 countries.