T-Oph Overdosage

No specific data are available. Overdosage is unlikely to occur as one 5 ml bottle of Timolol Eye Drops 0.5% contains 25 mg of Timolol maleate compared with the usual adult oral dose of 20-60 mg per day. However, in the rare event that overdosage occurs the most common signs and symptoms to be expected following overdosage with a beta-adrenergic receptor blocking agent are symptomatic bradycardia, hypotension, bronchospasm, and acute cardiac failure. If overdosage occurs, the following measures should be considered: Gastric lavage, if ingested. Studies have shown that timolol cannot be easily removed by hemodialysis.
Symptomatic bradycardia: Atropine sulphate, 0.25 to 2mg intravenously, should be used to induce vagal blockade. If bradycardia persists, intravenous isoprenaline hydrochloride should be administered cautiously. In refractory cases, the use of a cardiac pacemaker may be considered.
Hypotension: A sympathomimetic pressor agent such as dopamine, dobutamine or noradrenaline should be used. In refractory cases, the use of glucagon has been reported to be useful.
Bronchopasm: Isoprenaline hydrochloride should be used. Additional therapy with aminophylline may be considered.
Acute cardiac failure: conventional therapy with digitalis, diuretics and oxygen should be instituted immediately. In refractory cases, the use of intravenous aminophylline is suggested. This may be followed, if necessary, by glucagon which has been reported to be useful.
Heart block (second or third degree): Isoprenaline hydrochloride or a pacemaker should be used.