Timolol tablet overdosage: Difference between revisions
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== | ==Overdosage== | ||
Overdosage has been reported with timolol maleate tablets. A 30 year old female ingested 650 mg of timolol maleate (maximum recommended daily dose - 60 mg) and experienced second- and third-degree heart block. She recovered without treatment but approximately 2 months later developed irregular heart beat, hypertension, dizziness, tinnitus, faintness, increased pulse rate and borderline first degree heart block. | |||
The oral LD50 of the drug is 1190 and 900 mg/kg in female mice and female rats, respectively. | |||
<ref name="dailymed.nlm.nih.gov">{{Cite web | last = | first = | title = TIMOLOL MALEATE TABLET [MYLAN PHARMACEUTICALS INC.] | url = http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=57c62928-63d8-4505-9b9e-c085a3a12c95#nlm34089-3 | publisher = | date = | accessdate = }}</ref> | An in vitro hemodialysis study, using 14C timolol added to human plasma or whole blood, showed that timolol was readily dialyzed from these fluids; however, a study of patients with renal failure showed that timolol did not dialyze readily. | ||
The most common signs and symptoms to be expected with overdosage with a beta-adrenergic receptor blocking agent are symptomatic bradycardia, hypotension, bronchospasm, and acute cardiac failure. Therapy with timolol should be discontinued and the patient observed closely. The following additional therapeutic measures should be considered: | |||
(1) Gastric lavage. | |||
(2) Symptomatic bradycardia: Use atropine sulfate intravenously in a dosage of 0.25 mg to 2 mg to induce vagal blockade. If bradycardia persists, intravenous isoproterenol hydrochloride should be administered cautiously. In refractory cases the use of a transvenous cardiac pacemaker may be considered. | |||
(3) Hypotension: Use sympathomimetic pressor drug therapy, such as dopamine, dobutamine or norepinephrine. In refractory cases the use of glucagon hydrochloride has been reported to be useful. | |||
(4) Bronchospasm: Use isoproterenol hydrochloride. Additional therapy with aminophylline may be considered. | |||
(5) 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 hydrochloride which has been reported to be useful. | |||
(6) Heart block (second- or third-degree): Use isoproterenol hydrochloride or a transvenous cardiac pacemaker.<ref name="dailymed.nlm.nih.gov">{{Cite web | last = | first = | title = TIMOLOL MALEATE TABLET [MYLAN PHARMACEUTICALS INC.] | url = http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=57c62928-63d8-4505-9b9e-c085a3a12c95#nlm34089-3 | publisher = | date = | accessdate = }}</ref> | |||
==References== | ==References== | ||
Revision as of 01:16, 9 February 2014
| Timolol |
|---|
| TIMOLOL MALEATE® FDA Package Insert |
| Indications and Usage |
| Dosage and Administration |
| Contraindications |
| Warnings and Precautions |
| Adverse Reactions |
| Drug Interactions |
| Use in Specific Populations |
| Overdosage |
| Description |
| Clinical Pharmacology |
| How Supplied/Storage and Handling |
| Labels and Packages |
| Clinical Trials on Timolol |
| ClinicalTrials.gov |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overdosage
Overdosage has been reported with timolol maleate tablets. A 30 year old female ingested 650 mg of timolol maleate (maximum recommended daily dose - 60 mg) and experienced second- and third-degree heart block. She recovered without treatment but approximately 2 months later developed irregular heart beat, hypertension, dizziness, tinnitus, faintness, increased pulse rate and borderline first degree heart block.
The oral LD50 of the drug is 1190 and 900 mg/kg in female mice and female rats, respectively.
An in vitro hemodialysis study, using 14C timolol added to human plasma or whole blood, showed that timolol was readily dialyzed from these fluids; however, a study of patients with renal failure showed that timolol did not dialyze readily.
The most common signs and symptoms to be expected with overdosage with a beta-adrenergic receptor blocking agent are symptomatic bradycardia, hypotension, bronchospasm, and acute cardiac failure. Therapy with timolol should be discontinued and the patient observed closely. The following additional therapeutic measures should be considered:
(1) Gastric lavage.
(2) Symptomatic bradycardia: Use atropine sulfate intravenously in a dosage of 0.25 mg to 2 mg to induce vagal blockade. If bradycardia persists, intravenous isoproterenol hydrochloride should be administered cautiously. In refractory cases the use of a transvenous cardiac pacemaker may be considered.
(3) Hypotension: Use sympathomimetic pressor drug therapy, such as dopamine, dobutamine or norepinephrine. In refractory cases the use of glucagon hydrochloride has been reported to be useful.
(4) Bronchospasm: Use isoproterenol hydrochloride. Additional therapy with aminophylline may be considered.
(5) 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 hydrochloride which has been reported to be useful.
(6) Heart block (second- or third-degree): Use isoproterenol hydrochloride or a transvenous cardiac pacemaker.[1]
References
Adapted from the FDA Package Insert.