Ontel Ct

Ontel Ct Uses, Dosage, Side Effects, Food Interaction and all others data.

Chlortalidone prevents reabsorption of sodium and chloride by inhibiting the Na+/Cl− symporter in the distal convoluted tubule. Thiazides and related compounds also decrease the glomerular filtration rate, which further reduces the drug's efficacy in patients with kidney impairment (e.g. kidney insufficiency). By increasing the delivery of sodium to the distal renal tubule, chlortalidone indirectly increases potassium excretion via the sodium-potassium exchange mechanism (i.e. apical ROMK/Na channels coupled with basolateral NKATPases). This can result in hypokalemia and hypochloremia as well as a mild metabolic alkalosis; however, the diuretic efficacy of chlortalidone is not affected by the acid-base balance of the patient being treated.

Initially, diuretics lower blood pressure by decreasing cardiac output and reducing plasma and extracellular fluid volume. Eventually, cardiac output returns to normal, and plasma and extracellular fluid volume return to slightly less than normal, but a reduction in peripheral vascular resistance is maintained, thus resulting in an overall lower blood pressure. The reduction in intravascular volume induces an elevation in plasma renin activity and aldosterone secretion, further contributing to the potassium loss associated with thiazide diuretic therapy.

Angiotensin II is formed from angiotensin I in a reaction catalyzed by angiotensin-converting enzyme (ACE, kininase II). Angiotensin II is the principal pressor agent of the renin-angiotensin system, with effects that include vasoconstriction, stimulation of synthesis and release of aldosterone, cardiac stimulation, and renal reabsorption of sodium. Telmisartan blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively blocking the binding of angiotensin II to the AT1 receptor in many tissues, such as vascular smooth muscle and the adrenal gland. Its action is therefore independent of the pathways for angiotensin II synthesis.

There is also an AT2 receptor found in many tissues, but AT2 is not known to be associated with cardiovascular homeostasis. Telmisartan has a much greater affinity ( > 3,000 fold) for the AT1 receptor than for the AT2 receptor.

Blockade of the renin-angiotensin system with ACE inhibitors, which inhibit the biosynthesis of angiotensin II from angiotensin I, is widely used in the treatment of hypertension. ACE inhibitors also inhibit the degradation of bradykinin, a reaction also catalyzed by ACE. Because telmisartan does not inhibit ACE (kininase II), it does not affect the response to bradykinin. Whether this difference has clinical relevance is not yet known. Telmisartan does not bind to or block other hormone receptors or ion channels known to be important in cardiovascular regulation.

Blockade of the angiotensin II receptor inhibits the negative regulatory feedback of angiotensin II on renin secretion, but the resulting increased plasma renin activity and angiotensin II circulating levels do not overcome the effect of telmisartan on blood pressure.

Telmisartan is an orally active nonpeptide angiotensin II antagonist that acts on the AT1 receptor subtype. It has the highest affinity for the AT1 receptor among commercially available ARBS and has minimal affinity for the AT2 receptor. New studies suggest that telmisartan may also have PPARγ agonistic properties that could potentially confer beneficial metabolic effects, as PPARγ is a nuclear receptor that regulates specific gene transcription, and whose target genes are involved in the regulation of glucose and lipid metabolism, as well as anti-inflammatory responses. This observation is currently being explored in clinical trials. Angiotensin II is formed from angiotensin I in a reaction catalyzed by angiotensin-converting enzyme (ACE, kininase II). Angiotensin II is the principal pressor agent of the renin-angiotensin system, with effects that include vasoconstriction, stimulation of synthesis and release of aldosterone, cardiac stimulation, and renal reabsorption of sodium. Telmisartan works by blocking the vasoconstrictor and aldosterone secretory effects of angiotensin II.

Ontel Ct
Uses
Dosage
Side Effect
Precautions
Interactions
Uses during Pregnancy
Uses during Breastfeeding
Accute Overdose
Food Interaction
Half Life
Volume of Distribution
Clearance
Interaction With other Medicine
Contradiction
Storage

Trade Name	Ontel Ct
Generic	Chlorthalidone + Telmisartan
Type	Tablet
Therapeutic Class
Manufacturer	Cadell Healthcare Pvt Ltd
Available Country	India
Last Updated:	September 19, 2023 at 7:00 am

Uses

Chlorthalidone is used for the management of hypertension. Chlorthalidone is used for adjunctive therapy in edema associated with congestive heart failure, hepatic cirrhosis and corticosteroid and estrogen therapy.

Telmisartan is an angiotensin II receptor blocker (ARB) used for treatment of hypertension and Cardiovascular (CV) risk reduction in patients who are used for ACE inhibitors.

Ontel Ct is also used to associated treatment for these conditions: Calcium NephrolithiasisCardiovascular Events, Diabetic Nephropathy, Heart Failure, High Blood Pressure (Hypertension)

How Ontel Ct works

Chlorthalidone prevents reabsorption of sodium and chloride through inhibition of the Na+/Cl- symporter in the cortical diluting segment of the ascending limb of the loop of Henle. Reduction of sodium reabsorption subsequently reduces extracellular fluid and plasma volume via an osmotic, sodium-driven diuresis. By increasing the delivery of sodium to the distal renal tubule, Chlorthalidone indirectly increases potassium excretion via the sodium-potassium exchange mechanism. The exact mechanism of chlorthalidone's anti-hypertensive effect is under debate, however, it is thought that increased diuresis results in decreased plasma and extracellular fluid volume which therefore requires decreased cardiac output and overall lowers blood pressure. Chlorthalidone has also been shown to decrease platelet aggregation and vascular permeability, as well as promote angiogenesis in vitro, which is thought to be partly the result of reductions in carbonic anhydrase–dependent pathways. These pathways may play a role in chlorthalidone's cardiovascular risk reduction effects.

Telmisartan interferes with the binding of angiotensin II to the angiotensin II AT₁-receptor by binding reversibly and selectively to the receptors in vascular smooth muscle and the adrenal gland. As angiotensin II is a vasoconstrictor, which also stimulates the synthesis and release of aldosterone, blockage of its effects results in decreases in systemic vascular resistance. Telmisartan does not inhibit the angiotensin converting enzyme, other hormone receptors, or ion channels. Studies also suggest that telmisartan is a partial agonist of PPARγ, which is an established target for antidiabetic drugs. This suggests that telmisartan can improve carbohydrate and lipid metabolism, as well as control insulin resistance without causing the side effects that are associated with full PPARγ activators.

Dosage

Ontel Ct dosage

Therapy should be initiated with the lowest possible dose and then titrated according to individual patient response. A single dose given in the morning with food is recommended; divided doses are unnecessary.

Edema: Up to 50 mg daily.

Hypertension: 25 mg daily in the morning, increased to 50 mg daily if necessary.

Heart failure: 25-50 mg daily in the morning, increased if necessary to 100-200 mg daily (reduce to lowest effective dose for maintenance).

Maintenance doses may often be lower than initial doses and should be adjusted according to the individual patient.

Hypertension: Dosage must be individualized. The usual starting dose of Telmisartan tablets is 40 mg once a day. Blood pressure response is dose-related over the range of 20 to 80 mg

Most of the antihypertensive effect is apparent within 2 weeks and maximal reduction is generally attained after 4 weeks. When additional blood pressure reduction beyond that achieved with 80 mg Telmisartan is required, adiuretic may be added.

No initial dosage adjustment is necessary for elderly patients or patients with renal impairment, including those on hemodialysis. Patients ondialysismay develop orthostatic hypotension; their blood pressure should be closely monitored.

Cardiovascular Risk Reduction: The recommended dose of Telmisartan tablets is 80 mg once a day and can be administered with or without food. It is not known whether doses lower than 80 mg of telmisartan are effective in reducing the risk of cardiovascular morbidity and mortality.

When initiating Telmisartan therapy for cardiovascular risk reduction, monitoring of blood pressure is recommended, and if appropriate, adjustment of medications that lower blood pressure may be necessary.

Telmisartan tablets may be administered with other antihypertensive agents with or without food.

Side Effects

Dry mouth, thirst, nausea, vomiting, feeling weak, drowsy, restless, or light-headed, fast or uneven heartbeat, muscle pain or weakness, urinating less than usual or not at all, easy bruising or bleeding, unusual weakness, red or purple spots on skin, numbness or tingly feeling, nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools.

Most people tolerate telmisartan well. Side effects are usually minor and either require no treatment or can easily be treated by physician. The most common telmisartan side effects include-Upper respiratory infection such as the common cold or flu up to 7 percent of people, Back pain up to 3 percent of people, Diarrhea up to 3 percent of people, Inflammation of the sinuses up to 3 percent of people.

Toxicity

Intravenous LD₅₀ in rats is 150-200 mg/kg in males and 200 to 250 mg/kg in females. Acute oral toxicity is low: no deaths and no changes occurred in rats or dogs at 2000 mg/kg, the highest dose tested. Limited data are available with regard to overdosage in humans. The most likely manifestations of overdosage with telmisartan would be hypotension, dizziness and tachycardia; bradycardia could occur from parasympathetic (vagal) stimulation.

Precaution

Renal impairment: Chlorthalidone dosage should be reduced in moderate renal failure - every 24 or 48 h - and should not be used in advanced renal failure.

Liver disease: There is a risk of precipitating hepatic encephalopathy in patients with liver cirrhosis and ascites.

Use in pregnancy: It is better to avoid Chlorthalidone as it crosses the placenta.

Use in Lactation: In lactating mother, significant amount of Chlorthalidone enter breast milk; like other long-acting thiazides, it can suppress lactation. Chlorthalidone should not be prescribed for lactating mother.

Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Telmisartan may potentially cause extreme low blood pressure or a decrease in kidney function. Hyperkalemia may occur in patients on ARBs, particularly in patients with advanced renal impairment, heart failure, on renal replacement therapy or on potassium supplements, potassium-sparing diuretics, potassium containing salt substitutes or other drugs that increase potassium levels.

Interaction

Chlorthalidone may add to or potentiate the action of other antihypertensive drugs. Potentiation occurs with ganglionic peripheral adrenergic blocking drugs.

When certain medicines are taken together, there is a possibility of developing drug interactions. With Telmisartan, drugs such as potassium supplements or potassium-sparing diuretics may cause an interaction. When Telmisartan was co-administered with digoxin, median increases in digoxin peak plasma concentration (49%) and in through concentration (20%) where observed. Therefore, monitor digoxin levels when initiating, adjusting and discontinuing Telmisartan for the purpose of keeping the digoxin level within the therapeutic range. NSAID use may lead to increase risk of renal impairment and loss of antihypertensive effect. Monitor renal function periodically in patients receiving Telmisartan and NSAID therapy.

Volume of Distribution

Chlorthalidone has been shown to rapidly concentrate within erythrocytes and subsequently equilibrate via a slow diffusion back into the serum compartment, resulting in a large volume of distribution.

500 L

Elimination Route

Absolute bioavailability depends on dosage. Food slightly decreases the bioavailability (a decrease of about 6% is seen when the 40-mg dose is administered with food).

Half Life

40-50 hours

Bi-exponential decay kinetics with a terminal elimination half-life of approximately 24 hours.

Clearance

>800 mL/min

Elimination Route

Approximately 50% of the administered dose is excreted unmetabolized through the kidney, and excretion is characterized by biphasic elimination with a rapid phase followed by a slow secretory phase.

Following either intravenous or oral administration of 14C-labeled telmisartan, most of the administered dose (>97%) was eliminated unchanged in feces via biliary excretion; only minute amounts were found in the urine (0.91% and 0.49% of total radioactivity, respectively).

Pregnancy & Breastfeeding use

Pregnancy category B. Thiazides are excreted in human milk. Because of the potential for serious adverse reactions in nursing infants from chlorthalidone, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Telmisartan has been assigned to pregnancy categories C (use during first trimester) by the FDA. When pregnancy is detected or expected, Telmisartan should be discontinued as soon as possible. The use of drugs that act directly on the RAA system during the second and third trimesters has been associated with fetal and neonatal injury, including hypotension, neonatal skull hypoplasia, anuria, reversible or irreversible renal failure and death. There are no data on the excretion of Telmisartan into human milk, due to the potential for serious adverse effects in the nursing infant, a decision should be made to discontinue nursing or discontinue the drug.

Contraindication

Patients with anuria and known hypersensitivity to Chlorthalidone or other sulfonamide-derived drugs.

Telmisartan is contraindicated in conditions like Pregnancy, Adjunct in treatment of opioid dependence, Dry or painful cough. Telmisartan is also contraindicated in patients with known hypersensitivity to telmisartan.

Special Warning

Pediatric Use: Safety and effectiveness of Chlorthalidone tablets in pediatric patients have not been established.

Geriatric Use: Dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.

Renal Impairment: Severe impairment or on haemodialysis: Initially, 20 mg once daily.

Hepatic Impairment: Mild to moderate: Max: 40 mg once daily. Severe: Contraindicated.

Acute Overdose

Symptoms of acute overdosage include nausea, weakness, dizziness, and disturbances of electrolyte balance. The oral LD50 of the drug in the mouse and the rat is more than 25,000 mg/kg body weight. The minimum lethal dose (MLD) in humans has not been established. There is no specific antidote, but gastric lavage is recommended, followed by supportive treatment. Where necessary, this may include intravenous dextrose-saline with potassium, administered with caution.

Symptoms: Hypotension, bradycardia, tachycardia, dizziness, acute renal failure and elevated serum creatinine.

Management: Supportive and symptomatic treatment. Induction of emesis and/or gastric lavage. Activated charcoal may be useful. Salt and volume replacement should be given immediately if hypotension occurs and place patient in supine position.