Actions of Timozen in details
Timozen is a beta1 and beta2 (non-selective) adrenergic receptor blocking agent that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anesthetic (membrane-stabilizing) activity.
Timozen Ophthalmic Gel Forming Solution, when applied topically on the eye, has the action of reducing elevated, as well as normal intraocular pressure, whether or not accompanied by glaucoma. Elevated intraocular pressure is a major risk factor in the pathogenesis of glaucomatous visual field loss and optic nerve damage.
The precise mechanism of the ocular hypotensive action of Timozen Ophthalmic Gel Forming Solution is not clearly established at this time. Tonography and fluorophotometry studies of Timozen ophthalmic solution in man suggest that its predominant action may be related to reduced aqueous formation. However, in some studies, a slight increase in outflow facility was also observed.
Beta-adrenergic receptor blockade reduces cardiac output in both healthy subjects and patients with heart disease. In patients with severe impairment of myocardial function, beta-adrenergic receptor blockade may inhibit the stimulatory effect of the sympathetic nervous system necessary to maintain adequate cardiac function.
Beta-adrenergic receptor blockade in the bronchi and bronchioles results in increased airway resistance from unopposed parasympathetic activity. Such an effect in patients with asthma or other bronchospastic conditions is potentially dangerous.
How should I take Timozen?
Take Timozen exactly as it was prescribed for you. Do not take the medication in larger amounts or for longer than recommended by your doctor.
Take this medication with a full glass of water.
Take Timozen at the same time every day.
Do not skip doses or stop taking Timozen without first talking to your doctor. Stopping suddenly may make your condition worse.
To be sure this medication is helping your condition, your blood pressure will need to be checked on a regular basis. It is important that you not miss any scheduled visits to your doctor.
If you need to have any type of surgery, tell the surgeon that you are using Timozen. You may need to briefly stop using Timozen before having surgery.
Timozen is only part of a complete program of treatment for hypertension that may also include diet, exercise, and weight control. Follow your diet, medication, and exercise routines very closely if you are being treated for hypertension.
Hypertension often has no symptoms, so you may not even feel that you have high blood pressure. Continue using this medicine as directed, even if you feel well. You may need to use blood pressure medication for the rest of your life.
Store Timozen at room temperature away from moisture and heat.
Timozen administration
Use Timozen ophthalmic exactly as it was prescribed for you. Do not use the medication in larger amounts, or use it for longer than recommended by your doctor. Follow the instructions on your prescription label.
Wash your hands before using the eye drops.
Do not use this medication while you are wearing contact lenses. Timozen ophthalmic may contain a preservative that can be absorbed by soft contact lenses. Wait at least 15 minutes after using Timozen before putting your contact lenses in.
To apply the eye drops:
- Tilt your head back slightly and pull down your lower eyelid. Hold the dropper above the eye with the dropper tip down. Look up and away from the dropper as you squeeze out a drop, then close your eye.
- Gently press your finger to the inside corner of the eye (near your nose) for about 1 minute to keep the liquid from draining into your tear duct. If you use more than one drop in the same eye, wait about 5 minutes before putting in the next drop.
- Do not allow the dropper tip to touch any surface, including the eyes or hands. If the dropper becomes contaminated it could cause an infection in your eye, which can lead to vision loss or serious damage to the eye.
Do not use the eye drops if the liquid has changed colors or has particles in it. Call your doctor for a new prescription.
If you need to have any type of surgery, especially eye surgery, tell the surgeon ahead of time that you are using Timozen ophthalmic. You may need to stop using the medicine for a short time.
Store this medication at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use.
Timozen pharmacology
Timozen is a beta1 and beta2 (nonselective) adrenergic receptor blocking agent that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anesthetic activity.
Pharmacodynamics
Clinical pharmacology studies have confirmed the beta-adrenergic blocking activity as shown by (1) changes in resting heart rate and response of heart rate to changes in posture; (2) inhibition of isoproterenol-induced tachycardia; (3) alteration of the response to the Valsalva maneuver and amyl nitrite administration; and (4) reduction of heart rate and blood pressure changes on exercise.
Timozen decreases the positive chronotropic, positive inotropic, bronchodilator, and vasodilator responses caused by beta-adrenergic receptor agonists. The magnitude of this decreased response is proportional to the existing sympathetic tone and the concentration of Timozen at receptor sites.
In normal volunteers, the reduction in heart rate response to a standard exercise was dose dependent over the test range of 0.5 to 20 mg, with a peak reduction at 2 hours of approximately 30% at higher doses.
Beta-adrenergic receptor blockade reduces cardiac output in both healthy subjects and patients with heart disease. In patients with severe impairment of myocardial function beta-adrenergic receptor blockade may inhibit the stimulatory effect of the sympathetic nervous system necessary to maintain adequate cardiac function.
Beta-adrenergic receptor blockade in the bronchi and bronchioles results in increased airway resistance from unopposed parasympathetic activity. Such an effect in patients with asthma or other bronchospastic conditions is potentially dangerous.
Clinical studies indicate that Timozen at a dosage of 20 to 60 mg/day reduces blood pressure without causing postural hypotension in most patients with essential hypertension. Administration of Timozen to patients with hypertension results initially in a decrease in cardiac output, little immediate change in blood pressure, and an increase in calculated peripheral resistance. With continued administration of Timozen, blood pressure decreases within a few days, cardiac output usually remains reduced, and peripheral resistance falls toward pretreatment levels. Plasma volume may decrease or remain unchanged during therapy with Timozen. In the majority of patients with hypertension Timozen also decreases plasma renin activity. Dosage adjustment to achieve optimal antihypertensive effect may require a few weeks. When therapy with Timozen is discontinued, the blood pressure tends to return to pretreatment levels gradually. In most patients the antihypertensive activity of Timozen is maintained with long-term therapy and is well tolerated.
The mechanism of the antihypertensive effects of beta-adrenergic receptor blocking agents is not established at this time. Possible mechanisms of action include reduction in cardiac output, reduction in plasma renin activity, and a central nervous system sympatholytic action.
A Norwegian multi-center, double-blind study, which included patients 20 to 75 years of age, compared the effects of Timozen with placebo in 1,884 patients who had survived the acute phase of a myocardial infarction. Patients with systolic blood pressure below 100 mm Hg, sick sinus syndrome and contraindications to beta-blockers, including uncontrolled heart failure, second- or third-degree AV block and bradycardia (< 50 beats per minute), were excluded from the multi-center trial. Therapy with Timozen, begun 7 to 28 days following infarction, was shown to reduce overall mortality; this was primarily attributable to a reduction in cardiovascular mortality. Timozen significantly reduced the incidence of sudden deaths (deaths occurring without symptoms or within 24 hours of the onset of symptoms), including those occurring within one hour, and particularly instantaneous deaths (those occurring without preceding symptoms). The protective effect of Timozen was consistent regardless of age, sex or site of infarction. The effect was clearest in patients with a first infarction who were considered at a high risk of dying, defined as those with one or more of the following characteristics during the acute phase: transient left ventricular failure, cardiomegaly, newly appearing atrial fibrillation or flutter, systolic hypotension, or SGOT (ASAT) levels greater than four times the upper limit of normal. Therapy with Timozen also reduced the incidence of nonfatal reinfarction. The mechanism of the protective effect of Timozen is unknown.
Timozen was studied for the prophylactic treatment of migraine headache in placebo-controlled clinical trials involving 400 patients, mostly women between the ages of 18 and 66 years. Common migraine was the most frequent diagnosis. All patients had at least two headaches per month at baseline. Approximately 50 percent of patients who received Timozen had a reduction in the frequency of migraine headache of at least 50 percent, compared to a similar decrease in frequency in 30 percent of patients receiving placebo. The most common cardiovascular adverse effect was bradycardia (5%).
Pharmacokinetics and Metabolism
Timozen is rapidly and nearly completely absorbed (about 90%) following oral ingestion. Detectable plasma levels of Timozen occur within one-half hour and peak plasma levels occur in about one to two hours. The drug half-life in plasma is approximately 4 hours and this is essentially unchanged in patients with moderate renal insufficiency. Timozen is partially metabolized by the liver and Timozen and its metabolites are excreted by the kidney. Timozen is not extensively bound to plasma proteins; i.e., < 10% by equilibrium dialysis and approximately 60% by ultrafiltration. An in vitro hemodialysis study, using 14C Timozen added to human plasma or whole blood, showed that Timozen was readily dialyzed from these fluids; however, a study of patients with renal failure showed that Timozen did not dialyze readily. Plasma levels following oral administration are about half those following intravenous administration indicating approximately 50% first pass metabolism. The level of beta sympathetic activity varies widely among individuals, and no simple correlation exists between the dose or plasma level of Timozen and its therapeutic activity. Therefore, objective clinical measurements such as reduction of heart rate and/or blood pressure should be used as guides in determining the optimal dosage for each patient.
References
- DailyMed. "TIMOLOL: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
- NCIt. "Timolol Maleate: NCI Thesaurus (NCIt) provides reference terminology for many systems. It covers vocabulary for clinical care, translational and basic research, and public information and administrative activities.". https://ncit.nci.nih.gov/ncitbrowser... (accessed September 17, 2018).
- EPA DSStox. "(S)-Timolol: DSSTox provides a high quality public chemistry resource for supporting improved predictive toxicology.". https://comptox.epa.gov/dashboard/ds... (accessed September 17, 2018).
Reviews
The results of a survey conducted on ndrugs.com for Timozen are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Timozen. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.User reports
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Information checked by Dr. Sachin Kumar, MD Pharmacology
