Xstan H 12.5/40mg Tablet 15s

Xstan H 12 5 40mg Tablet 15s is a fixed-dose combination of two antihypertensive agents: telmisartan, an angiotensin II receptor blocker (ARB), and hydrochlorothiazide (Hydrochlorothiazide ), a thiazide diuretic. Together, they lower blood pressure through complementary and synergistic mechanisms. Telmisartan blocks the renin-angiotensin-aldosterone system (RAAS), causing vasodilation (widening of the blood vessels) and reducing aldosterone-mediated sodium retention. Hydrochlorothiazide independently reduces plasma volume through renal sodium and water removal. Their combination provides superior blood pressure lowering compared to either agent alone, with a mutually offsetting side effect profile.

Xstan H 12 5 40mg Tablet 15s is recommended for hypertension management in patients whose blood pressure is not adequately controlled by either agent alone, or as initial therapy in patients likely to require two antihypertensive agents. The combination is available as fixed-dose tablets.

Telmisartan is a long-acting, highly selective ARB, which can provide sustained 24-hour blood pressure control with just one dose. It prevents vasoconstriction (narrowing of blood vessels) and aldosterone release. It also helps the body use insulin more effectively and improves blood fat levels, which is not seen with other ARBs. When hydrochlorothiazide reduces blood volume by flushing out sodium and water, the body fights back by activating the RAAS. RAAS is a hormonal system that tries to raise blood pressure back up, which would partially undermine hydrochlorothiazide's effect. Telmisartan blocks the exact receptor that this counterresponse depends on, neutralising it completely. This means both drugs work in the same direction rather than against each other, which is what makes the combination significantly more effective than either drug used alone.

Hypertension

Most effective when a single antihypertensive agent provides insufficient blood pressure control.

Hypertension with metabolic syndrome or diabetes

Telmisartan enhances insulin sensitivity, aids lipid and improves glucose metabolism.

Cardiovascular risk reduction

Effective in patients with hypertension and established cardiovascular disease or high cardiac risk.

Hypertension with oedema

The Hydrochlorothiazide component also manages fluid retention.

• Better blood pressure control as compared to either agent as monotherapy.

• Hydrochlorothiazide-induced RAAS activation is directly counteracted by telmisartan's AT1 blockade.

• Telmisartan's 24-hour half-life ensures consistent once-daily blood pressure control, including the critical early-morning surge period.

• Hypokalemia (low potassium levels) and hyperglycaemia (high blood sugar levels) caused by hydrochlorothiazide are partially offset by telmisartan's aldosterone-blocking effect and PPAR-gamma-mediated insulin-sensitising effect, respectively.

• A single-tablet combination improves medication adherence compared to single formulations.

Common side effects

• Dizziness and light-headedness, especially while starting the medication

• Increased urination

• Hypokalaemia (lower chances)

• Upper respiratory tract infections

• Back pain

Uncommon side effects

• Hypotension (low blood pressure), particularly in volume-depleted patients

• Hyperuricaemia (excess uric acid in the blood), which may result in a gout flare

• Mild rise in serum creatinine

• Skin photosensitivity

• Erectile dysfunction

Serious side effects requiring immediate attention

• Hyperkalaemia (high potassium levels), especially in patients with renal impairment or those on other potassium-sparing drugs

• Acute kidney injury, especially in people with bilateral renal artery stenosis (narrowing of both the arteries that supply the kidneys)

• Angioedema (swelling under the tissue of the skin), even though rare, is potentially life-threatening

• Severe hyponatraemia (low sodium levels) causing confusion or seizures

Take once daily, with or without food, at the same time each day, preferably in the morning. Swallow whole with water. Do not crush or chew tablets. Ensure adequate hydration. Do not stop taking Xstan H 12 5 40mg Tablet 15s abruptly, as blood pressure may rebound sharply. If a dose is missed and it is already close to the next scheduled time, skip the missed dose.

Blood pressure depends on two things: how hard the heart pumps (cardiac output) and how much resistance the blood vessels offer (peripheral vascular resistance). Both are regulated by the renin-angiotensin-aldosterone system (RAAS) and by how well the kidneys excrete sodium. Angiotensin II (AngII) is the primary mediator hormone of the RAAS. In hypertension, excessive RAAS activity or poor sodium removal results in an increase in blood pressure.

Telmisartan works by blocking the AT1 receptor, which is the main receptor that AngII binds to. By blocking this receptor on blood vessel walls, the adrenal gland, the kidneys, and the heart, telmisartan:

• Prevents AngII from constricting blood vessels, causing them to relax and widen, lowering blood pressure)

• Stops AngII from triggering aldosterone release from the adrenal gland, reducing sodium and water retention and preserving potassium

• Prevents the long-term structural damage AngII causes to the heart and blood vessel walls.

Telmisartan also weakly activates a receptor called PPAR-gamma inside fat cells, which improves insulin sensitivity and aids lipid and glucose metabolism.

Hydrochlorothiazide blocks NCC, preventing this reabsorption. The sodium and chloride that cannot be reabsorbed remain in the tubule, and water follows them by osmosis, increasing urine output (diuresis) and reducing the total volume of fluid in the bloodstream. This reduction in blood volume decreases the pressure the heart has to work against, lowering blood pressure for a short period of time.

When the kidneys sense low blood pressure, they release renin, stimulating AngII production to raise blood pressure. In combination with telmisartan, this compensatory AngII cannot activate AT1 receptors, blocking the counterregulatory response.

Telmisartan's blockade of aldosterone release partially compensates for the potassium loss typically caused by hydrochlorothiazide when used alone.

• Potassium-rich foods or potassium chloride salts (KCl) (CAUTION): Telmisartan raises potassium by blocking aldosterone. Excessive dietary potassium or KCl salt substitutes may cause hyperkalaemia (extremely high levels of potassium).

• High-sodium diet (MODERATE): Opposes the antihypertensive effect of both agents. Follow a reduced-sodium diet.

• Alcohol (MODERATE): Increases the likelihood of vasodilation (widening of blood vessels) and hypotensive effects, increasing dizziness and fall risk. Limit consumption.

• Liquorice root (CAUTION): Contains glycyrrhizin, which promotes sodium retention and potassium removal, opposing Hydrochlorothiazide's effects and worsening hypokalaemia.

ACE inhibitors (enalapril, ramipril)

SEVERE

Double RAAS blockade (ARB + ACEi) significantly increases hyperkalaemia, hypotension, and acute kidney injury risk.

Potassium-sparing diuretics / Potassium supplements

SEVERE

Additive hyperkalaemia risk with telmisartan's aldosterone blockade.

NSAIDs (ibuprofen, naproxen)

MODERATE

Reduce antihypertensive and diuretic effects; increase risk of acute kidney injury, especially in elderly or volume-depleted patients.

Lithium

SEVERE

Hydrochlorothiazide lowers renal clearance of lithium, causing lithium accumulation and toxicity.

Digoxin

CAUTION

Hydrochlorothiazide-induced hypokalaemia heightens the risk of digoxin toxicity. Monitor potassium and digoxin levels closely.

• Bilateral renal artery stenosis: ARBs can reduce GFR drastically by causing vasodilation, increasing the risk of acute kidney injury. Hence, it must not be used in such patients.

• Hyperkalaemia: Telmisartan further increases potassium by blocking aldosterone. Contraindicated in pre-existing hyperkalaemia.

• Diabetes mellitus: Hydrochlorothiazide may impair glucose tolerance; telmisartan's PPAR-gamma activity may partially offset this. Monitor blood glucose closely.

• Gout: Hydrochlorothiazide can increase uric acid accumulation, so it should be used with caution in gout or hyperuricaemia.

• Hepatic impairment: Telmisartan is predominantly cleared through the liver; hence, people with severe liver disease should use it with caution.

Overdose may cause severe hypotension (from both vasodilation and volume depletion), bradycardia or tachycardia, acute kidney injury, severe electrolyte disturbances (hypokalaemia, hyponatraemia), and hyperkalaemia in patients with renal impairment. Treatment may include fluid resuscitation, electrolyte correction, vasopressors if required, and cardiac monitoring. Telmisartan is highly protein-bound and not significantly removed by haemodialysis. Seek immediate emergency medical attention.

Take the missed dose as soon as you remember on the same day. If it is the next day, skip the missed dose and continue your regular schedule. Never double the dose. Consistent daily dosing is important for maintaining optimal blood pressure control. Monitor your blood pressure if possible after a missed dose.