Dosing and uses of Blocadren, Timol (timolol)
Adult dosage forms and strengths
tablet
- 5mg
- 10mg
- 20mg
Hypertension
10-30 mg PO q12hr
Maintenance: 20-40 mg/day
No more than 60 mg/day
Acute Myocardial Infarction
10 mg PO q12hr
Angina (Off-label)
15-45 mg/day PO divided q6-8hr
Migraine, Prophylaxis
Initial: 10 mg PO q12hr
Titrate to 10-30 mg/day
Additional Information
Less effective than thiazide diuretics in black and geriatric patients
Shown to decrease mortality in hypertension and post-myocardial infarction
Other Indications & Uses
Off-label: angina pectoris
Pediatric dosage forms and strengths
<18 years old: safety & efficacy not established
Geriatric dosage forms and strengths
Hypertension
10-30 mg PO q12hr
Maintenance: 20-40 mg/day
No more than 60 mg/day
Acute Myocardial Infarction
10 mg PO q12hr
Angina (Off-label)
15-45 mg/day PO divided q6-8hr
Migraine, ProphylaxisInitial
10 mg PO q12hr
Titrate to 10-30 mg/day
Blocadren, Timol (timolol) adverse (side) effects
1-10% (selected)
Arrythmia
Bradycardia
Syncope
Fatigue
Headache
Dyspnea
<1% (selected)
Bronchospasm
Chest pain
Edema
Paresthesia
Nausea
Rales
Frequency not defined
Depression, decreased exercise tolerance, Raynaud's phenomenon
May increase triglyceride levels and insulin resistance, and decrease HDL levels
Warnings
Black box warnings
May exacerbate ischemic heart disease following abrupt withdrawaL
Hypersensitivity to catecholamines has been observed during withdrawaL
Exacerbation of angina and, in some cases, myocardial infarction occurrence after abrupt discontinuation
When discontinuing chronically administered beta-blockers (particularly with ischemic heart disease) gradually reduce dose over 1-2 wk and carefully monitor
If angina markedly worsens or acute coronary insufficiency develops, reinstate beta-blocker administration promptly, at least temporarily (in addition to other measures appropriate for unstable angina)
Warn patients against interruption or discontinuation of beta-blocker without physician advice
Because coronary artery disease is common and may be unrecognized, slowly discontinue beta-blocker therapy, even in patients treated only for hypertension
Contraindications
Bronchial asthma/COPd
Overt cardiac failure, sinus bradycardia, 2°/3° heart block, cardiogenic shock
Hypersensitivity
Sick sinus syndrome without permanent pacemaker
Cautions
IDDM, peripheral vascular disease, cerebrovascular insufficiency, liver disease, renal impairment, CHF, thyrotoxicosis
Sudden discontinuation can exacerbate angina and lead to myocardial infarction
Anesthesia/surgery (myocardial depression)
Use in pheochromocytoma
Increased risk of stroke after surgery
Pregnancy and lactation
Pregnancy category: C
Lactation: excreted in milk; Mfr's recommends avoid nursing (AAP Committee states compatible with nursing)
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Blocadren, Timol (timolol)
Mechanism of action
Blocks response to beta-adrenergic stimulation to beta1 and beta2 receptors; may reduce blood pressure by decreasing sympathetic outflow; produces negative chronotropic and inotropic activity through unknown mechanism
Pharmacokinetics
Half-Life elimination: 2-2.7 hr
Peak Plasma Time: 1-2 hr
Duration: 4 hr
Absorption: 90%
Vd: 1.7 L/kg
Bioavailability: 50%
Protein Bound: 60%
Dialyzable: No
Metabolism: Liver, extensive first-pass
Excretion: Urine (15-20%)
Onset of Action
- Hypotensive: 15-45 min
- Peak effect: 0.5-2.5 hr
