Brimonidine + Timolol


Concise Prescribing Info
Indications/Uses
Reduction of raised intraocular pressure.
Dosage/Direction for Use
Adult : Ophth Instill 1 drop into affected eye(s) bid.
Dosage Details
Ophthalmic
Reduction of raised intraocular pressure
Adult: Instill 1 drop into affected eye(s) bid.
Contraindications
Reactive airway disease including bronchial asthma or history of bronchial asthma, severe COPD; sinus bradycardia, sick sinus syndrome SA block, 2nd- or 3rd-degree AV block. Childn (<2 yr). Concomitant use w/ MAOIs and antidepressants (e.g. TCAs and mianserin).
Special Precautions
Patient w/ 1st-degree AV block, severe peripheral circulatory disturbance/disorders (e.g. Raynaud’s phenomenon), mild to moderate COPD, metabolic acidosis and untreated phaechromocytoma, corneal disease, depression, DM, myasthenia gravis. May mask signs and symptoms of acute hypoglycaemia. Pregnancy and lactation.
Adverse Reactions
Ocular hypersensitivity, conjunctival hyperaemia, burning sensation, stinging sensation in the eye, allergic conjunctivitis, corneal erosion, superficial punctuate keratitis, eye pruritus, conjunctival folliculosis, visual disturbance, blepharitis, epiphora; eye dryness, discharge, pain and irritation; foreign body sensation, depression, somnolence, headache, HTN, oral dryness; eyelid oedema, pruritus and erythema; asthenic conditions.
Patient Counseling Information
May cause transient vision blurring, visual disturbances, fatigue and/or drowsiness, if affected, do not drive or operate machinery.
MonitoringParameters
Monitor intraocular pressure and BP.
Drug Interactions
Potential additive effect w/ systemic antihypertensives e.g. β-adrenergic blockers, Ca channel blockers. May result to mydriasis w/ epinephrine. May increase hypoglycaemic effect of antidiabetics. May potentiate hypertensive reaction to sudden clonidine withdrawal. May increase risk of hypotension w/ anaesth drugs.
Potentially Fatal: May reduce therapeutic effect w/ TCAs and mianserin.
Action
Description: Brimonidine tartrate is a relatively selective α2-adrenergic agonist, it reduces aqueous humour formation and increases uveoscleral outflow. Timolol maleate blocks β1 and β2 adrenergic receptors, it reduces aqueous humour production or outflow, and BP by blocking adrenergic receptors and reducing sympathetic outflow. It blocks β1 adrenergic receptors to produce negative chronotropic and inotropic activity.
Onset: Peak ocular hypotensive effects: 2 hr (brimonidine); 1-2 hr (timolol).
Pharmacokinetics:
Absorption: Time to peak plasma concentration: W/in 0.5-4 hr (brimonidine); approx 1-2 hr (timolol).
Distribution: Timolol: Crosses the placenta and enters breast milk. Plasma protein binding: 10-60%.
Metabolism: Undergoes extensive hepatic metabolism (brimonidine); partial hepatic metabolism (timolol).
Excretion: Via urine (as metabolites and unchanged drug). Half-life: 2-3 hr (brimonidine); 4 hr (timolol).
Chemical Structure

Chemical Structure Image
Brimonidine

Source: National Center for Biotechnology Information. PubChem Database. Brimonidine, CID=2435, https://pubchem.ncbi.nlm.nih.gov/compound/Brimonidine (accessed on Jan. 21, 2020)


Chemical Structure Image
Timolol

Source: National Center for Biotechnology Information. PubChem Database. Timolol, CID=33624, https://pubchem.ncbi.nlm.nih.gov/compound/Timolol (accessed on Jan. 21, 2020)

Storage
Store between 15-25°C. Protect from light.
References
Anon. Brimonidine and Timolol. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 04/03/2016.

Buckingham R (ed). Timolol Maleate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 04/03/2016.

Combigan 0.2%/0.5% Ophthalmic Solution. U.S. FDA. https://www.fda.gov/. Accessed 04/03/2016.

Combigan Solution/Drops (Allergan, Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 04/03/2016.

Joint Formulary Committee. Brimonidine with Timolol. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 04/03/2016.

McEvoy GK, Snow EK, Miller J et al (eds). Brimonidine Tartrate (EENT). AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 04/03/2016.

McEvoy GK, Snow EK, Miller J et al (eds). Timolol maleate. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 04/03/2016.

Disclaimer: This information is independently developed by MIMS based on Brimonidine + Timolol from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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