Timoprost
Timoprost Uses, Dosage, Side Effects, Food Interaction and all others data.
Latanoprost is an analogue of prostaglandin F2α. Latanoprost is a prostanoid selective FP receptor agonist that is believed to reduce the intraocular pressure (IOP) by increasing the outflow of aqueous humor. Studies in animals and man suggest that the main mechanism of action is increased uveoscleral outflow. Elevated IOP represents a major risk factor for glaucomatous field loss. The higher the level of IOP, the greater the likelihood of optic nerve damage and visual field loss.
Latanoprost effectively decreases intraocular pressure by increasing uveoscleral outflow. A decrease in intraocular pressure has been measured within 3–4 hours post-administration, reaches a maximum decrease at 8–12 hours, and can be maintained for a period of 24 hours.
A note on eye and periorbital changes
Between 3 to 10% of patients taking latanoprost have experienced iris pigmentation after about 3-4 months of latanoprost use. Patients should be notified of this risk before initiating treatment. It may occur in both patients with light-colored irides (green-brown or blue/grey-brown) or dark-colored (brown) irides, but is less pronounced in the latter group. This drug may also cause other ocular effects including infrequent conjunctival hyperemia, pigmentation of periocular tissues, eyelash changes, hypertrichosis, and ocular irritation.
| Trade Name | Timoprost |
| Generic | Latanoprost + Timolol (Maleate) |
| Weight | 05%w/v, 0.5%w/v |
| Type | Eye Drops |
| Therapeutic Class | |
| Manufacturer | Vega Pharmaceuticals Ltd, |
| Available Country | Pakistan |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
Latanoprost Sterile Ophthalmic Solution is used for the reduction of elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension.
Timoprost is also used to associated treatment for these conditions: Increased Intra Ocular Pressure (IOP), Ocular Hypertension, Open Angle Glaucoma (OAG)
How Timoprost works
Elevated intraocular pressure leads to an increased risk of glaucomatous visual field loss. The higher the intraocular pressure, the higher the risk of damage to the optic nerve and loss of visual field. Latanoprost selectively stimulates the prostaglandin F2 alpha receptor and this results in a decreased intraocular pressure (IOP) via the increased outflow of aqueous humor, which is often implicated in cases of elevated intraocular pressure. Possible specific mechanisms of the abovementioned increased aqueous outflow are the remodeling of the extracellular matrix and regulation of matrix metalloproteinases. These actions result in higher tissue permeability related to humor outflow pathways, which likely change outflow resistance and/or outflow rates.
Dosage
Timoprost dosage
The recommended dosage is 1 drop (1.5 mcg) in the affected eye(s) once daily in the evening. This is for topical ophthalmic use only. Not for injection or oral use.
Side Effects
Eyelash changes (increased length, thickness, pigmentation, and number of lashes); eyelid skin darkening; intraocular inflammation (iritis/uveitis); iris pigmentation changes; and macular edema, including cystoid macular edema. The ocular adverse events and ocular signs and symptoms reported in 5- 15% of the patients on latanoprost in the 6 month, multicenter, double-masked, active-controlled trials were blurred vision, burning and stinging, conjunctival hyperemia, foreign body sensation, itching, increased pigmentation of the iris, and punctate epithelial keratopathy. Local conjunctiva hyperemia was observed; however, less than 1% of the latanoprost treated patients required discontinuation of therapy because of intolerance to conjunctival hyperemia.
Toxicity
The oral LD50 in the rat is > 50 mg/kg.
An overdose of latanoprost is not expected to result in dangerous patient outcomes, however, conjunctival or episcleral hyperemia may occur.An intravenous infusion of 3 μg/kg of latanoprost in healthy volunteers led to mean plasma concentrations of 200 times higher than a normally administered therapeutic dose and no adverse effects were noted. One study suggested that an overdose of latanoprost lead to cystoid macular edema after a large, unintended overdose. This resolved within 4 weeks after 4 weeks following treatment with nepafenac 0.3% eye drops in addition to oral acetazolamide. Contact the local poison control center for updated guidance on the management of a latanoprost overdose.
Precaution
Ophthalmic Solution may gradually increase the pigmentation of the iris. The eye color change is due to increased melanin content in the stromal melanocytes of the iris rather than to an increase in the number of melanocytes. During clinical trials, the increase in brown iris pigment has not been shown to progress further upon discontinuation of treatment, but the resultant color change may be permanent. Eyelid skin darkening, which may be reversible. There may be increased length, thickness, pigmentation, the number of lashes or hairs, and misdirected growth of eyelashes. Eyelash changes are usually reversible upon discontinuation of treatment. It should be used with caution in patients with a history of intraocular inflammation (iritis/uveitis) and should generally not be used in patients with active intraocular inflammation. This drug should be used with caution in patients who do not have an intact posterior capsule or who have known risk factors for macular edema.
Interaction
In vitro studies have shown that precipitation occurs when eye drops containing thimerosal are mixed with latanoprost. If such drugs are used they should be administered with an interval of at least 5 minutes between applications.
Volume of Distribution
The volume of distribution of latanoprost is 0.16 ± 0.02 L/kg. The activated acid form of latanoprost can be measured in aqueous humor in the initial 4 hours post-administration, and it is measured in the plasma only for 1 hour following ophthalmic administration. This drug is more lipophilic than its parent prostaglandin and easily penetrates the cornea. It has been shown to cross the placenta in rats.
Elimination Route
This drug is rapidly absorbed in the cornea as an isopropyl ester prodrug and is then activated by the process of hydrolysis. A small amount of this drug is systemically absorbed. The Cmax of latanoprost in the systemic circulation is reached after 5 minutes and is measured to be 53 pg/mL. The Cmax in the aqueous humor is attained within 2 hours after administration. and has been estimated to be 15-30 ng/mL.
Half Life
The elimination half-life of latanoprost from the plasma is about 17 minutes. The elimination half-life of latanoprost from the eye is estimated at 2–3 hours.
Clearance
The systemic clearance of latanoprost is 7 mL/min/kg.
Elimination Route
After hepatic beta-oxidation, the metabolites of latanoprost are primarily found to be excreted by the kidneys. About 88% of the latanoprost dose is recovered in the urine after topical administration. About 15% of a dose is reported to be excreted in the feces.
Pregnancy & Breastfeeding use
Pregnancy Category C. There are no adequate and well controlled studies in pregnant women. The drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Contraindication
Known hypersensitivity to latanoprost, benzalkonium chloride or any other ingredients in this product.
Special Warning
Pediatric Use: Safety and effectiveness in pediatric patients have not been established.
Geriatric Use: No overall differences in safety or effectiveness have been observed between elderly and younger patients.
Storage Condition
Before opening the cap, keep the bottle in its box in a refrigerator (2°-8° C) protected from light. After opening, keep the bottle in its box in a cool place below 25° C. The contents should be used within one month after the dropper is opened. Keep out of reach of children
Innovators Monograph
You find simplified version here Timoprost
