Timolol is a

beta blocker Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms, and to protect the heart from a second heart attack after a first heart attack ( secondary prevention). They are ...

medication used either by mouth or as

eye drops Eye drops or eyedrops are liquid drops applied directly to the surface of the eye usually in small amounts such as a single drop or a few drops. Eye drops usually contain saline to match the salinity of the eye. Drops containing only saline an ...

. As eye drops it is used to treat increased

pressure inside the eye Intraocular pressure (IOP) is the fluid pressure inside the eye. Tonometry is the method eye care professionals use to determine this. IOP is an important aspect in the evaluation of patients at risk of glaucoma. Most tonometers are calibrated to ...

such as in ocular hypertension and

glaucoma Glaucoma is a group of eye diseases that result in damage to the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, in which the drainage angle for fluid within the eye re ...

. By mouth it is used for

high blood pressure Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high b ...

, chest pain due to insufficient blood flow to the heart, to prevent further complications after a

heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which m ...

, and to prevent migraines. Common side effects with the drops is irritation of the eye. Common side effects by mouth include tiredness, slow heart beat, itchiness, and

shortness of breath Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing di ...

. Other side effects include masking the symptoms of low blood sugar in those with

diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level (hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...

. Use is not recommended in those with

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, c ...

, uncompensated

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

, or

COPD Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by long-term respiratory symptoms and airflow limitation. The main symptoms include shortness of breath and a cough, which may or may not produce ...

. It is unclear if use during pregnancy is safe for the baby. Timolol is a non-selective beta blocker. Timolol was patented in 1968, and came into medical use in 1978. It is on the

World Health Organization's List of Essential Medicines The WHO Model List of Essential Medicines (aka Essential Medicines List or EML), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health s ...

. Timolol is available as a

generic medication A generic drug is a pharmaceutical drug that contains the same chemical substance as a drug that was originally protected by chemical patents. Generic drugs are allowed for sale after the patents on the original drugs expire. Because the active c ...

. In 2020, it was the 143rd most commonly prescribed medication in the United States, with more than 4million prescriptions.

Medical uses

By mouth

In its by mouth or oral form, it is used: * to treat

* to prevent

s * to prevent

migraine Migraine (, ) is a common neurological disorder characterized by recurrent headaches. Typically, the associated headache affects one side of the head, is pulsating in nature, may be moderate to severe in intensity, and could last from a few ho ...

headaches The combination of timolol and the alpha-1 blocker prazosin has

sedative A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are CNS depressants and interact with brain activity causing its deceleration. Various kinds of sedatives can be distinguished, but ...

effects.

Eye drops

In its eye drop form it is used to treat open-angle and, occasionally, secondary glaucoma. The mechanism of action of timolol is probably the reduction of the formation of aqueous humor in the ciliary body in the eye. It was the first

approved for topical use in treatment of glaucoma in the United States (1978). When used by itself, it depresses

intraocular pressure Intraocular pressure (IOP) is the fluid pressure inside the eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response fu ...

(IOP) 18–34% below baseline within first few treatments. However, there are short-term escape and long-term drift effects in some people. That is, tolerance develops. It may reduce the extent of the diurnal IOP curve up to 50%. The IOP is higher during sleep. Efficacy of timolol in lowering IOP during the sleep period may be limited. It is a 5–10× more potent β-blocker than

propranolol Propranolol, sold under the brand name Inderal among others, is a medication of the beta blocker class. It is used to treat high blood pressure, a number of types of irregular heart rate, thyrotoxicosis, capillary hemangiomas, performance a ...

. Timolol is light-sensitive; it is usually preserved with 0.01% benzalkonium chloride (BAC), but also comes BAC-free. It can also be used in combination with pilocarpine, carbonic anhydrase inhibitors or

prostaglandin The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are der ...

analogs. A Cochrane review compared the effect of timolol versus

brimonidine Brimonidine is a medication used to treat open-angle glaucoma, ocular hypertension, and rosacea. In rosacea it improves the redness. It is used as eye drops or applied to the skin. Common side effects when used in the eyes include itchiness, re ...

in slowing the progression of open angle glaucoma in adults but found insufficient evidence to come to conclusions.

On the skin

In its gel form it is used on the skin to treat infantile hemangiomas.

Contraindications

The medication should not be taken by individuals with: * An allergy to timolol or any other beta-blockers *

Asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, c ...

or severe chronic obstructive bronchitis * A slow heart rate (bradycardia), or a heart block *

Heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

Side effects

The most serious possible side effects include cardiac

arrhythmia Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults ...

s and severe

bronchospasm Bronchospasm or a bronchial spasm is a sudden constriction of the muscles in the walls of the bronchioles. It is caused by the release ( degranulation) of substances from mast cells or basophils under the influence of anaphylatoxins. It causes ...

s. Timolol can also lead to fainting,

congestive heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

, depression,

confusion In medicine, confusion is the quality or state of being bewildered or unclear. The term "acute mental confusion"

, worsening of Raynaud's syndrome and impotence. Side effects when given in the eye include: burning sensation, eye redness, superficial punctate keratopathy, corneal numbness.

Formulations

It is available in tablet and liquid formulations. For ophthalmic use, timolol is also available combined: * with carbonic anhydrase inhibitors: ** timolol and brinzolamide ** timolol and dorzolamide * with α₂ agonists: ** timolol and brimonidine * with

prostaglandin analogs Prostaglandin analogues are a class of drugs that bind to a prostaglandin receptor. Wider use of prostaglandin analogues is limited by unwanted side effects and their abortive potential. Uses Prostaglandin analogues such as misoprostol are used ...

: ** timolol and latanoprost ** timolol and travoprost

Brand names

Timolol is marketed under many

trade name A trade name, trading name, or business name, is a pseudonym used by companies that do not operate under their registered company name. The term for this type of alternative name is a "fictitious" business name. Registering the fictitious name ...

s worldwide. Timolol eye drops are marketed under the brand name Istalol among others.

References

External links

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