Timolol: Difference between revisions

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{{MedTemplate

| generic = Timolol

| generic = Timolol (maleate)

| brand = Blocadren

| brand = Timoptic (ophthalmic), Timoptic-XE (gel-forming once-daily), Istalol (once-daily 0.5%), Betimol; Blocadren (oral, discontinued in many markets); combination eye drops Combigan (with brimonidine), Cosopt (with dorzolamide)

| classes = Beta blocker

| structure =

| ~~intro~~ = ~~Timolol~~ is ~~a non~~-selective ~~beta~~ blocker. ~~In addition to cardiovascular uses~~, it is ~~widely used as an eye drop in~~ the ~~treatment of glaucoma~~.

| classes = [[:Category:Beta blockers|Beta blocker (non-selective)]], [[:Category:Antiglaucoma medicines|Antiglaucoma medicine]], [[:Category:Antihypertensives|Antihypertensive]], [[:Category:Migraine prophylactics|Migraine prophylactic]]

| uses = <vote slug="open-angle-glaucoma-use">Open-angle glaucoma and ocular hypertension (FDA, ophthalmic; the dominant current use)</vote>, <vote slug="hypertension-use">Hypertension (FDA, oral)</vote>, <vote slug="post-mi-use">Post-myocardial-infarction secondary prevention (FDA, oral)</vote>, <vote slug="migraine-prophylaxis-use">Migraine prophylaxis (FDA, oral)</vote>

| starting_dose = Ophthalmic: 1 drop 0.5% in affected eye(s) BID (or once daily for XE / Istalol). Oral hypertension: 10 mg PO BID, titrate to 60 mg/day. Migraine prophylaxis: 10 mg BID, titrate to 30 mg/day

| preparations = Tablets 5, 10, 20 mg; ophthalmic solution 0.25%, 0.5%; ophthalmic gel-forming solution 0.25%, 0.5% (Timoptic-XE)

| fda_max = 60 mg/day (oral, hypertension); 0.5% BID (ophthalmic)

| pill_id =

| routes = Oral, ophthalmic

| onset = BP effect within hours (oral); IOP reduction within 30 minutes, full effect 1-2 weeks (ophthalmic)

| duration = 12 hours (oral BID); 24 hours (Timoptic-XE)

| halflife = ~4 hours (oral)<ref name="timoptic-label">FDA Prescribing Information, Timoptic (timolol maleate ophthalmic solution), Bausch & Lomb/Merck, current revision. https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/018086s068lbl.pdf</ref>

| bioavailability = ~50% (oral); systemic absorption from ophthalmic application is clinically meaningful via nasolacrimal drainage<ref name="timoptic-label" />

| pregnancy = Limited human data; β-blocker class effects include fetal growth restriction and neonatal bradycardia/hypoglycemia.{{citation needed}}

| legal = [[USLegal:Prescription only|Rx-only]] in US

| mechanism = <vote slug="timolol-mech-claim">Non-selective β1 and β2 adrenergic receptor antagonist. Ophthalmic application reduces aqueous humor production at ciliary-body β2 receptors, lowering intraocular pressure 20-30%, the basis of the glaucoma indication. Systemic oral use achieves the standard β-blocker effects on heart rate, contractility, and renin secretion.</vote> '''Systemic absorption from eye drops is clinically meaningful''' via nasolacrimal drainage, producing bradycardia, bronchospasm (worth considering in asthma and COPD), and hypoglycemia masking in diabetic patients. '''Nasolacrimal occlusion''' (pressing on the inner canthus for 1-2 minutes after instillation) reduces systemic exposure by approximately 70% and is the standard counseling pearl<ref name="timoptic-label" />.

}}

== References ==

[[Category:Beta blockers]]

[[Category:Antiglaucoma medicines]]

[[Category:Antihypertensives]]

[[Category:Migraine prophylactics]]

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