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Timolol information from DrugsUpdate  

See Available Brands of Timolol in India

P - Contraindicated in pregnancy

Timolol is a beta-blocker. It works by interfering with body chemicals that shrink blood vessels and interfere with normal heart contractions. Timolol is used to treat hypertension (high blood pressure). It is also used to help prevent a second heart attack in patients who have survived a first heart attack and are stable and to prevent migraines.

Pharmacodynamics

Pharmacokinetics

Timolol is a non-selective β-adrenergic receptor blocker which does not have significant intrinsic sympathomimetic, direct myocardial depressant or local anaesthetic activity. It decreases intraocular pressure by reducing aqueous humor formation or increase outflow.

Onset

Topical: 30 minutes.

Duration

As long as 24 hours.

Absorption
Almost completely absorbed from GI tract. Peak plasma concentration in 1-2 hours.

Distribution
Protein-binding: Low. Crosses the placenta and distributed into breastmilk.

Metabolism
Undergo first-pass metabolism. Plasma half-life: 4 hours.

Excretion
Excreted in urine as metabolites and unchanged drug.

Timolol Indications / Timolol Uses

Information Not Available

Timolol Adverse Reactions / Timolol Side Effects

Fatigue, coldness of extremities, paraesthesia, GI symptoms, skin rash, alopecia, dry mouth, bradycardia. Ophthalmic use: Blurred vision, burning, stinging, ocular irritation, decreased corneal sensitivity, visual disturbances, diplopia, ptosis, cystoid macular oedema, pseudopemphigoid, choroidal detachment following filtration surgery. Systemic absorption with systemic effects may occur.

Potentially Fatal: Heart failure, heart block, bronchospasm, respiratory failure.

Precautions

Impaired Hepatic or Renal Function
Since Timolol is partially metabolized in the liver and excreted mainly by the kidneys, dosage reductions may be necessary when hepatic and/or renal insufficiency is present.

Dosing in the Presence of Marked Renal Failure
Although the pharmacokinetics of Timolol are not greatly altered by renal impairment, marked hypotensive responses have been seen in patients with marked renal impairment undergoing dialysis after 20 mg doses. Dosing in such patients should therefore be especially cautious.

Muscle Weakness
Beta-adrenergic blockade has been reported to potentiate muscle weakness consistent with certain myasthenic symptoms (e.g., diplopia, ptosis, and generalized weakness). Timolol has been reported rarely to increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms.

Cerebrovascular Insufficiency
Because of potential effects of beta-adrenergic blocking agents relative to blood pressure and pulse, these agents should be used with caution in patients with cerebrovascular insufficiency. If signs or symptoms suggesting reduced cerebral blood flow are observed, consideration should be given to discontinuing these agents.

Overdosage
Symptomatic bradycardia, hypotension, bronchospasm and acute heart failure. Gastric lavage followed by symptomatic and supportive treatment.

Special Precautions

Due to systemic absorption, side effects associated with β-blockers may occur. Heart block, cerebrovascular insufficiency, myasthenia gravis. May mask signs of hypoglycaemia, hyperthyroidism. Abrupt withdrawal may precipitate thyroid storm in patients suspected of developing thyrotoxicosis. Avoid sudden withdrawal in patients with ischaemic heart disease.

Other Drug Interactions

Hypotensive action may be reduced by NSAIDs. Increased hypotensive effect of antihypertensives, aldesleukin, general anaesthetics, catecholamine-depleting drugs e.g. reserpine. Increased risk of bradycardia with digoxin. Decreased response to sympathomimetics. Increased timolol levels with CYP2D6 inhibitors e.g. quinidine. Increased risk of prolongation of AV conduction with calcium-channel blockers and digoxin. May exacerbate rebound hypertension following discontinuance of clonidine. Additive effects on β-blockade with other β-blockers.

Other Interactions

Information Not Available

Dosage

Oral
Hypertension
Adult: As maleate: 10 mg daily, increased according to response every 7 or more days. Maintenance: 10-40 mg/day in single or 2 divided doses. Max: 60 mg daily. Doses >30 mg should be given in 2 divided doses.

Renal impairment: Dose reduction may be needed.
Hepatic impairment: Dose reduction may be needed.

Oral

Prophylaxis of migraine
Adult: As maleate: 10-20 mg daily in 1-2 divided doses. Max: 30 mg daily.

Renal impairment: Dose reduction may be needed.
Hepatic impairment: Dose reduction may be needed.

Oral
Angina pectoris
Adult: As maleate: 5 mg bid, increased every 3 or more days to not > 10 mg daily. Maintenance: 35-45 mg daily in divided doses. Max: 60 mg daily.

Renal impairment: Dose reduction may be needed.
Hepatic impairment: Dose reduction may be needed.

Oral
Post myocardial infarction
Adult: As maleate: Initially, 5 mg bid for 2 days, starting 1-4 weeks after MI, increased up to 10 mg bid, if necessary.

Renal impairment: Dose reduction may be needed.
Hepatic impairment: Dose reduction may be needed.

Ophthalmic
Open-angle glaucoma
Adult: Eye drop: Initially, instil 1 drop of 0.25% solution bid, increased to 0.5% solution if there is inadequate response; decrease to 1 drop daily if controlled. Gel-forming eyedrop: Instil 1 drop of 0.25% or 0.5% preparation in affected eyes once daily.

Ophthalmic
Ocular hypertension
Adult: Eye drop: Initially, instil 1 drop of 0.25% solution bid, increased to 0.5% solution if there is inadequate response; decrease to 1 drop daily if controlled. Gel-forming eyedrop: Instil 1 drop of 0.25% or 0.5% preparation in affected eyes once daily.

Food(before/after)

Should be taken with food

List of Contraindications

Timolol and Pregnancy

Contraindicated in pregnancy

Category C: Either studies in animals have revealed adverse effects on the foetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the foetus.

In 2nd & 3rd trimesters.

Category D: There is positive evidence of human foetal risk, but the benefits from use in pregnant women may be acceptable despite the risk (e.g., if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective).

Timolol and Lactation

Information Not Available

Timolol and Children

Information Not Available

Timolol and Geriatic

Safety and effectiveness in pediatric patients have not been established.

Timolol and Other Contraindications

Present or history of bronchial asthma, COPD, present or history of bronchospastic disease, sinus bradycardia, 2nd and 3rd degree heart block, overt heart failure, cardiogenic shock. Pregnancy.

Storage

Ophthalmic
Store at 15-30°C (59-86°F).

Oral

Store at 15-30°C (59-86°F).

Lab interference

Ophthalmic
Store at 15-30°C (59-86°F).

Oral

Store at 15-30°C (59-86°F).

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