Blocadren (Timolol) Drug Information: Overdosage and Contraindications

Pill Identifier Search

May 25, 2012

Blocadren

Palpitations »

What are palpitations?

Palpitations are unpleasant sensations of irregular and/or forceful beating of the heart. Some persons with palpitations have no heart disease or abnormal heart rhythms and the reasons for their palpitations are unknown. In others, palpitations result from abnormal heart rhythms (arrhythmias).

Arrhythmias refer to heartbeats that are too slow, too rapid, irregular, or too early.
Rapid arrhythmias (greater than 100 beats per minute) are called tachycardias.
Slow arrhythmias (slower than 60 beats per minute) are called bradycardias.
Irregular heart rhythms are called fibrillations (as in atrial fibrillation).
When a single heartbeat occurs earlier than normal, it is called a premature contraction, and this can cause the sensation of a forceful heartbeat.
Abnormalities in the atria, the ventricles, and the elect...

Read the Palpitations article »

« Previous
1
2
3
4
5
6
7
8
9
10
11
12
13
Next »

Blocadren User Reviews >>

Blocadren

Heart Disease Slideshow Pictures

Medical Illustrations of the Heart Image Collection

Take the Heart Disease Quiz!

font size

OVERDOSE

Overdosage has been reported with Tablets BLOCADREN (timolol) . A 30-year-old female ingested 650 mg of BLOCADREN (timolol) (maximum recommended daily dose — 60 mg) and experienced second and third degree heart block. She recovered without treatment but approximately two months later developed irregular heartbeat, 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 BLOCADREN (timolol) should be discontinued and the patient observed closely. The following additional therapeutic measures should be considered:

Gastric lavage.
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.
Hypotension: Use sympathomimetic pressor drug therapy, such as dopamine, dobutamine or levarterenol. In refractory cases the use of glucagon hydrochloride has been reported to be useful.
Bronchospasm: Use isoproterenol hydrochloride. 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 hydrochloride which has been reported to be useful.
Heart block (second or third degree): Use isoproterenol hydrochloride or a transvenous cardiac pacemaker.

CONTRAINDICATIONS

BLOCADREN (timolol) is contraindicated in patients with bronchial asthma or with a history of bronchial asthma, or severe chronic obstructive pulmonary disease (see WARNINGS); sinus bradycardia; second and third degree atrioventricular block; overt cardiac failure (see WARNINGS); cardiogenic shock; hypersensitivity to this product.

Last reviewed on RxList: 12/9/2008
This monograph has been modified to include the generic and brand name in many instances.