TIMOPTIC
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TIMOPTIC (TIMOPTIC).
Non-selective beta-adrenergic receptor antagonist (beta-blocker). Reduces intraocular pressure by decreasing aqueous humor production, likely via blockade of beta-2 receptors in the ciliary epithelium.
| Metabolism | Partially metabolized in the liver by CYP2D6; significant first-pass metabolism after systemic absorption. |
| Excretion | Renal elimination: ~20% unchanged; biliary/fecal elimination: ~80% as metabolites. |
| Half-life | Terminal elimination half-life is approximately 4-6 hours in healthy adults; prolonged in renal impairment. |
| Protein binding | ~60% bound to plasma proteins (mainly albumin). |
| Volume of Distribution | Approximately 1.5 L/kg; distributes widely into tissues. |
| Bioavailability | Ophthalmic: systemic bioavailability ~20-30% after topical administration due to nasolacrimal drainage. |
| Onset of Action | Ophthalmic: 0.5 hours for intraocular pressure reduction. |
| Duration of Action | Ophthalmic: 12-24 hours; typically dosed once or twice daily. |
| Molecular Weight | 316.42 |
One drop of 0.25% or 0.5% solution in the affected eye(s) twice daily.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No dosage adjustment required; timolol is primarily metabolized in the liver and excreted renally as metabolites with minimal active drug. Caution in severe renal impairment (CrCl <30 mL/min) due to potential systemic accumulation. |
| Liver impairment | No specific Child-Pugh based recommendations; use with caution in severe hepatic impairment due to reduced metabolism. |
| Pediatric use | Instill one drop of 0.25% solution in the affected eye(s) twice daily. For children with inadequate response, may increase to 0.5% solution twice daily. |
| Geriatric use | Start with the lowest concentration (0.25%) and monitor for systemic effects; elderly may be more sensitive to bradycardia and hypotension. |
| 1st trimester | Risk of fetal bradycardia and reduced placental perfusion; consider benefit vs risk. |
| 2nd trimester | May cause fetal growth restriction; monitor fetal growth and heart rate. |
| 3rd trimester | Risk of neonatal bradycardia, hypotension, and hypoglycemia if used near term. |
Clinical note
Comprehensive clinical and safety monograph for TIMOPTIC (TIMOPTIC).
| Placental transfer | Timolol crosses the placenta; detectable in fetal plasma at levels similar to maternal. |
| Breastfeeding | Timolol is excreted into breast milk in small amounts. Monitor infant for bradycardia, hypotension, and signs of beta-blockade. Use with caution, especially in preterm or low-birth-weight infants. |
| Lactation Rating |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Bronchial asthmaSevere chronic obstructive pulmonary diseaseSinus bradycardiaSecond- or third-degree atrioventricular blockCardiogenic shockOvert cardiac failure
| Precautions | May mask signs of hypoglycemia and thyrotoxicosis, Exacerbation of bronchospasm in patients with asthma or COPD, Bradycardia and heart block, especially in patients with pre-existing conduction abnormalities, Rebound hypertension after abrupt discontinuation in patients with coronary artery disease, Increased risk of anaphylactic reactions and resistance to epinephrine treatment, Systemic absorption can occur with ophthalmic use leading to systemic beta-blockade effects |
| Food/Dietary | No significant food interactions have been reported with timolol ophthalmic solution. However, patients should avoid excessive alcohol intake as it may theoretically exacerbate systemic side effects such as hypotension or dizziness. |
Loading safety data…
| L3 (Moderately Safe) |
| Teratogenic Risk | Timolol is an ophthalmic beta-blocker. Systemic absorption is low but possible. Animal studies show no teratogenicity; human data are limited. First trimester: Risk cannot be excluded; consider benefit vs risk. Second/third trimesters: Potential for fetal bradycardia, growth restriction, and hypoglycemia; use with caution. |
| Fetal Monitoring | Maternal: Heart rate, blood pressure, signs of bronchospasm. Fetal: Ultrasound for growth, fetal heart rate monitoring to detect bradycardia; consider non-stress test if concerns. |
| Fertility Effects | Animal studies indicate no significant impact on fertility. Human data are lacking; theoretical effect from systemic beta-blockade on reproductive function is unlikely at ophthalmic doses. |
| Clinical Pearls | Timolol ophthalmic solution is a non-selective beta-blocker used to reduce intraocular pressure (IOP). It may exacerbate asthma, COPD, bradycardia, heart block, or heart failure due to systemic absorption. Use with caution in patients with diabetes as it can mask hypoglycemia symptoms. Assess for contraindications like reactive airway disease or sinus bradycardia before initiating. Monitor IOP regularly; therapeutic effect may take several weeks. Advise patients to apply pressure to the nasolacrimal duct (punctal occlusion) for 1-2 minutes after instillation to minimize systemic absorption. |
| Patient Advice | Instill one drop in the affected eye(s) once or twice daily as prescribed. · Do not touch the dropper tip to your eye or any surface to avoid contamination. · Apply gentle pressure to the inner corner of the eye (near the nose) for 1-2 minutes after each drop to reduce side effects. · Do not use while wearing contact lenses; remove lenses prior to instillation and wait at least 15 minutes before reinserting. · Contact your doctor if you experience shortness of breath, slow heartbeat, dizziness, or fainting. · This medication may cause blurred vision temporarily; do not drive or operate machinery until vision clears. · Do not stop using this medication abruptly without consulting your doctor. · Keep medication tightly closed and store at room temperature away from light and moisture. |