Lr H

Uses

Hydrochlorothiazide is used for-

• Edema associated with congestive heart failure, hepatic cirrohosis, various forms of renal dysfunction and corticosteroid and estrogen therapy
• Management of hypertension either as the sole therapeutic agent or to enhance the effectiveness of other antihypertensive drugs in the more severe form of hypertension
• Management of diabetes insipidus
• Management of proximal renal tubular acidosis
• Idiopathic hypercalciuria and calcium nephrolithiasis, osteoporosis and exercise induced hyperkalemia

Losartan is an angiotensin II receptor blocker (ARB) used for:

• Treatment of hypertension, to lower blood pressure in adults and children greater than 6 years old. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions.
• Reduction of the risk of stroke in patients with hypertension and left ventricular hypertrophy. There is evidence that this benefit does not apply to Black patients.
• Treatment of diabetic nephropathy with an elevated serum creatinine and proteinuria in patients with type 2 diabetes and a history of hypertension.

Ramiprilis used for the following cases:

• Mild to severe hypertension
• Congestive Heart failure.
• To reduce the risk of stroke, myocardial infarction and death from cardiovascular events in patients with a history of cardiovascular disease.
• Proteinuric non-diabetic nephropathy.

Lr H is also used to associated treatment for these conditions: Acidosis, Renal Tubular, Calcium Nephrolithiasis, Cirrhosis of the Liver, Congestive Heart Failure (CHF), Diabetes Insipidus, Edema, High Blood Pressure (Hypertension), Hypertension,Essential, Hypokalemia caused by diuretics, Nephrotic Syndrome, Premenstrual tension with edema, Sodium retention, Stroke, Prophylaxis of preeclampsiaDiabetic Nephropathy, Heart Failure, High Blood Pressure (Hypertension), Marfan Syndrome, StrokeCardiovascular Events, Diabetic Nephropathy, Heart Failure, Heart Failure With Reduced Ejection Fraction (HFrEF), High Blood Pressure (Hypertension), Myocardial Infarction, Nondiabetic proteinuric chronic kidney disease, Stroke, High risk cardiovascular event

How Lr H works

Hydrochlorothiazide is transported from the circulation into epithelial cells of the distal convoluted tubule by the organic anion transporters OAT1, OAT3, and OAT4. From these cells, hydrochlorothiazide is transported to the lumen of the tubule by multidrug resistance associated protein 4 (MRP4).

Normally, sodium is reabsorbed into epithelial cells of the distal convoluted tubule and pumped into the basolateral interstitium by a sodium-potassium ATPase, creating a concentration gradient between the epithelial cell and the distal convoluted tubule that promotes the reabsorption of water.

Hydrochlorothiazide acts on the proximal region of the distal convoluted tubule, inhibiting reabsorption by the sodium-chloride symporter, also known as Solute Carrier Family 12 Member 3 (SLC12A3). Inhibition of SLC12A3 reduces the magnitude of the concentration gradient between the epithelial cell and distal convoluted tubule, reducing the reabsorption of water.

Losartan reversibly and competitively prevents angiotensin II binding to the AT₁ receptor in tissues like vascular smooth muscle and the adrenal gland. Losartan and its active metabolite bind the AT₁ receptor with 1000 times more affinity than they bind to the AT₂ receptor. The active metabolite of losartan is 10-40 times more potent by weight than unmetabolized losartan as an inhibitor of AT₁ and is a non-competitive inhibitor. Losartan's prevention of angiotensin II binding causes vascular smooth muscle relaxation, lowering blood pressure.

Angiotensin II would otherwise bind to the AT₁ receptor and induce vasoconstriction, raising blood pressure.

Ramipril inhibits the RAAS system by binding to and inhibiting ACE thereby preventing the conversion of angiotensin I to angiotensin II. As plasma levels of angiotensin II fall, less activation of the G-protein coupled receptors angiotensin receptor I (AT₁R) and angiotensin receptor II (AT₂R) occurs.

AT₁R mediates vasoconstriction, inflammation, fibrosis, and oxidative stress through a variety of signaling pathways. These include G_q coupling to the inositol triphosphate pathway, activation of phospholipases C, A₂, and D which contribute to eicosanoid production, activation of Ca^{2+ These counteracting effects are shared by the Mas receptor which is activated by Ang(1-7), a subtype of angiotensin produced by plasma esterases from AngI or by ACE2 from AngII produced through a secondary pathway by tonin and cathepsin G. Ang(1-7) also activates AT₂R although the bulk of its effect is mediated by MasR.}

ACE is also responsible for the breakdown of bradykinin. The resulting buildup of bradykinin due to ACE inhibition is thought to mediate the characteristic dry-cough as a side effect of ACE inhibitor medications.

Dosage

Lr H dosage

Adults-

For Edema: The usual adult dosage is 25 to 100 mg daily as a single or divided dose.

For Control of Hypertension: The usual initial dose in adults is 25 mg daily given as a single dose. The dose may be increased to 50 mg daily, given as a single or two divided doses. Doses above 50 mg are often associated with marked reductions in serum potassium. In some patients (especially the elderly) an initial dose of 12.5 mg daily may be sufficient.

Infants and children-

For diuresis and for control of hypertension: The usual pediatric dosage is 1 to 2 mg/kg/day in single or two divided doses, not to exceed 37.5 mg per day in infants up to 2 years of age or 100 mg per day in children 2 to 12 years of age. In infants less than 6 months of age, doses up to 3 mg/kg/day in two divided doses may be required.

Hypertension:

• Usual adult dose: 50 mg once daily.
• Usual pediatric starting dose: 0.7 mg per kg once daily (up to 50 mg).

Hypertensive Patients with Left Ventricular Hypertrophy:

• Usual starting dose: 50 mg once daily.
• Add hydrochlorothiazide 12.5 mg and/or increase Losartan to 100 mg followed by an increase to hydrochlorothiazide 25 mg if further blood pressure response is needed.

Nephropathy in Type 2 Diabetic Patients:

• Usual dose: 50 mg once daily.
• Increase dose to 100 mg once daily if further blood pressure response is needed.

Use in elderly:

• Patients up to 75 years: No initial dosage adjustment is necessary for this group of patients.
• Patients over 75 years: A lower starting dose of 25 mg once daily is recommended.

Dosage of Ramipril must be adjusted according to the patient tolerance and response.

Hypertension: For the management of hypertension in adults not receiving a diuretic, the usual initial dose of Ramipril is 1.25 - 2.5 mg once daily. Dosage generally is adjusted no more rapidly than at 2 week intervals. The usual maintenance dosage in adults is 2.5 - 20 mg daily given as a single dose or in 2 divided doses daily. If BP is not controlled with Ramipril alone, a diuretic may be added.

Congestive heart failure after myocardial infarction: In this case, Ramipril therapy may be initiated as early as 2 days after myocardial infarction. An initial dose of 2.5 mg twice daily is recommended, but if hypotension occurs, dose should be reduced to 1.25 mg twice daily. Therapy is then titrated to a target daily dose of 5 mg twice daily.

Prevention of major cardiovascular events: In this case, the recommended dose is 2.5 mg once daily for the first week of therapy and 5 mg once daily for the following 3 weeks; dosage then may be increased, as tolerated, to a maintenance dosage of 10 mg once daily.

Side Effects

Generally, Hydrochlorothiazide is well tolerated. However, a few side effects may occur like weakness, restlessness, dizziness, headache, fever, diarrhea, vomiting, sialadenitis, cramping, constipation, gastric irritation, nausea, anorexia, and hypotension. In rare case hyperglycemia, glycosuria, hyperuricemia and muscle spasm may occur.

In controlled clinical trials in patients with essential hypertension, dizziness was the only side effect reported that occurred with an incidence greater than placebo in 1% or more of patients treated with Losartan. Rarely, rash was reported although the incidence in controlled clinical trials was less than placebo. Angioedema, involving swelling of the face, lips and/or tongue has been reported rarely in patients treated with Losartan. Serious hypotension (particularly on initiating treatment in salt-depleted patients) or renal failure (mainly in patients with renal artery stenosis) may be encountered during Losartan treatment.

Ramipril is generally well tolerated. Dizziness, headache, fatigue and asthenia are commonly reported side effects. Other side effects occurring less frequently include symptomatic hypotension, cough, nausea, vomiting, diarrhoea, rash, urticaria, oliguria, anxiety, amnesia etc. Angioneurotic oedema, anaphylactic reactions and hyperkalaemia have also been reported rarely.

Toxicity

The oral LD₅₀ of hydrochlorothiazide is >10g/kg in mice and rats.

Patients experiencing an overdose may present with hypokalemia, hypochloremia, and hyponatremia. Treat patients with symptomatic and supportive treatment including fluids and electrolytes. Vasopressors may be administered to treat hypotension and oxygen may be given for respiratory impairment.

The oral TDLO in mice is 1000mg/kg and in rats is 2000mg/kg. In humans the TDLO for men is 10mg/kg/2W and for women is 1mg/kg/1D.

Symptoms of overdose are likely to include hypotension, tachycardia, or bradycardia due to vagal stimulation. Supportive treatment should be instituted for symptomatic hypotension. Hemodialysis will not remove losartan or its active metabolite due to their high rates of protein binding.

Symptoms of overdose may include excessive peripheral vasodilation (with marked hypotension and shock), bradycardia, electrolyte disturbances, and renal failure. Cases of ACE inhibitor induced hepatotoxicity have been reported in humans and presented as acute jaundice and elevated liver enzymes. Removal of the ACE inhbitor resulted in a decline in liver enzymes and re-challenge produced a subsequent increase.

There were no observed tumerogenic effects at chronic doses up to 500mg/kg/day to rats for 24 months or at doses up to 1000mg/kg/day to mice for 18 months. For both species doses were administered by gavage and equivalent to 200 time the maximum recommended human exposure based on body surface area.

No mutagenic activity was detected in the Ames test in bacteria, the micronucleus test in mice, unscheduled DNA synthesis in a human cell line, or a forward gene-mutation assay in a Chinese hamster ovary cell line. Several metabolites of ramipril also produced negative results in the Ames test.

No effects on fertility were seen in rats at doses up to 500mg/kg/day. No teratogenicity was observed in rats and cynomolgus monkeys at doses 400 times the maximum recommended human exposure nor in rabbites at 2 times the maximum recommended human exposure.

LD₅₀ 10 g/kg (rat). LD₅₀ 10.5 g/kg (mouse). LD₅₀ 1 g/kg (dog).

Precaution

Thiazides should be used with caution in patients with severe renal disease, impaired hepatic function or progressive liver disease and gout.

A lower dose should be considered for patients with a history of hepatic and renal impairment. Losartan should not be used with potassium-sparing diuretic

Ramipril should be used with caution in patients with impaired renal function, hyperkalaemia, hypotension, and impaired hepatic function.

Interaction

Alcohol, Barbiturates, or Narcotics: Potentiation of orthostatic hypotension may occur.

Antidiabetic Drugs (oral agents and insulin): Thiazides can impair control of diabetes mellitus by diet and antidiabetic Drugs. Antihypertensive Drugs: Additive effect or potentiation.

No drug interaction of clinical significance has been identified. Compounds which have been studied in clinical pharmacokinetic trials include hydrochlorothiazide, digoxin, warfarin, cimetidine, ketoconazole and phenobarbital.

With Diuretics: Patients on diuretics, especially those in whom diuretic therapy was recently instituted, may occasionally experience an excessive reduction of blood pressure after initiation of therapy with ramipril.

With Potassium Supplements and Potassium-sparing Diuretics: Ramipril can attenuate potassium loss caused by thiazide diuretics. Potassium-sparing diuretics (spironolactone, amiloride, triamterene, and others) or potassium supplements can increase the risk of hyperkalemia.

Other: Neither ramipril nor its metabolites have been found to interact with food, digoxin, antacid, furosemide, cimetidine, indomethacin, and simvastatin. The combination of ramipril and propranolol showed no adverse effects on dynamic parameters (blood pressure and heart rate). The co-administration of ramipril and warfarin did not adversely affect the anticoagulant effects of the latter drug.

Volume of Distribution

The volume of distribution varies widely from one study to another with values of 0.83-4.19L/kg.

The volume of distribution of losartan is 34.4±17.9L and 10.3±1.1L for the active metabolite (E-3174).

Elimination Route

An oral dose of hydrochlorothiazide is 65-75% bioavailable, with a T_max of 1-5 hours, and a C_max of 70-490ng/mL following doses of 12.5-100mg. When taken with a meal, bioavailability is 10% lower, C_max is 20% lower, and T_max increases from 1.6 to 2.9 hours.

Losartan is approximately 33% orally bioavailable. Losartan has a T_max of 1 hour and the active metabolite has a T_max of 3-4 hours. Taking losartan with food decreases the C_max but does only results in a 10% decrease in the AUC of losartan and its active metabolite. A 50-80mg oral dose of losartan leads to a C_max of 200-250ng/mL.

The extent of absorption is at least 50-60%.. Food decreases the rate of absorption from the GI tract without affecting the extent of absorption. The absolute bioavailabilities of ramipril and ramiprilat were 28% and 44%, respectively, when oral administration was compared to intravenous administration. The serum concentration of ramiprilat was unchanged when capsules were opened and the contents dissolved in water, dissolved in apple juice, or suspended in apple sauce.

Half Life

The plasma half life of hydrochlorothiazide is 5.6-14.8h.

The terminal elimination half life of losartan is 1.5-2.5 hours while the active metabolite has a half life of 6-9 hours.

Plasma concentrations of ramiprilat decline in a triphasic manner. Initial rapid decline represents distribution into tissues and has a half life of 2-4 hours. The half life of the apparent elimination phase is 9-18 hours, which is thought to represent clearance of free drug. The half-life of the terminal elimination phase is > 50 hours and thought to represent clearance of drug bound to ACE due to its slow dissociation. The half life of ramiprilat after multiple daily doses (MDDs) is dose-dependent, ranging from 13-17 hours with 5-10 mg MDDs to 27-36 hours for 2.5 mg MDDs.

Clearance

The renal clearance of hydrochlorothiazide in patients with normal renal function is 285mL/min. Patients with a creatinine clearance of 31-80mL/min have an average hydroxychlorothiazide renal clearance of 75mL/min, and patients with a creatinine clearance of ≤30mL/min have an average hydroxychlorothiazide renal clearance of 17mL/min.

Losartan has a total plasma clearance of 600mL/min and a renal clearance of 75mL/min. E-3174, the active metabolite, has a total plasma clearance of 50mL/min and a renal clearance of 25mL/min.

The renal clearance of ramipril and ramiprilat was reported to be 7.2 and 77.4 mL/min/1.73m². The mean renal clearance of ramipril and ramiprilat is reported to be 10.7 and 126.8 mL/min in healthy elderly patients with normal renal function, additionally the Cmax of ramiprilat is approximately 20% higher in this population. While the pharmacokinetics of ramipril appear unaffected by reduced renal function, the plasma concentration and half-life of ramiprilat are increased. In patient's with hepatic failure the concentration of ramipril is initially increased while the tmax of ramiprilat is prolonged due to a reduced ability to metabolize the drug. However, steady state concentrations of ramiprilat are the same in hepatic failure as in healthy patients.

Elimination Route

Hydrochlorothiazide is eliminated in the urine as unchanged hydrochlorothiazide.

A single oral dose of losartan leads to 4% recovery in the urine as unchanged losartan, 6% in the urine as the active metabolite. Oral radiolabelled losartan is 35% recovered in urine and 60% in feces. Intravenous radiolabelled losartan is 45% recovered in urine and 50% in feces.

Following oral administration, about 60% of the dose is eliminated in the urine as unchanged ramipril (6

Pregnancy & Breastfeeding use

Pregnancy: Evidence of fetal risk in hydrochlorothiazide therapy is found, but it is indicated if benefits outweigh risks. Thiazides are indicated in pregnancy when edema is due to pathologic causes.\

Lactation: Neonatal side effects have been seen incase of hydrochlorothiazide therapy and therefore it is not recommended.

Although there is no experience with the use of Losartan in pregnant women, animal studies with Losartan potassium have demonstrated fetal and neonatal injury and death, the mechanism of which is believed to be pharmacologically mediated through effects on the renin angiotensinaldosterone system. Losartan should not be used in pregnancy and if pregnancy is detected Losartan should be discontinued as soon as possible.

It is not known whether Losartan is excreted in human breast milk. However, significant level of Losartan found in rat milk which suggests that the drug should not be used in lactating mother.

If pregnancy is detected, ramipril should be discontinued as early as possible unless continued use is considered life saving. Ramipril should not be used during lactation.

Contraindication

Hydrochlorothiazide is contraindicated to the patients of anuria and those who are sensitive to hydrochlorothiazide or to other sulfonamide-derived drugs. Therapy is not to be initiated in diabetes mellitus.

It is also contraindicated to patients who are hypersensitive to any component of this product. In patients who are intravenously volume depleted (e.g. those treated with high dose diuretics), symptomatic hypotension may occur. These conditions Losartan potassium should be corrected prior to administer Losartan or a lower starting dose (usually 25 mg) should be used.

It is contraindicated in patients who are hypersensitive to any component of this product and in patients with a history of angioedema related to previous treatment with a ACE inhibitor.

Special Warning

Elderly: in some patients specially the elderly an initial dose of 12.5 mg daily may be sufficient.

Children: An initial dose for children has been 1 to 2 mg per kg body-weight in 2 divided doses. Infants under 6 months may need doses upto 3 mg per kg daily.

No initial dosage adjustment is necessary in patients with mild renal impairment (CrCl 20-50 ml/min). For patients with moderate to severe renal impairment (CrCl <20 ml/min) or patients on dialysis, a lower starting dose of 25 mg is recommended.

Dosage in renal impairment: For the patients with hypertension and renal impairment, the recommended initial dose is 1.25 mg Ramipril once daily. Subsequent dosage should be titrated according to individual tolerance and BP response, up to a maximum of 5 mg daily. For the patients with heart failure and renal impairment, the recommended dose is 1.25 mg once daily. The dose may be increased to 1.25 mg twice daily and up to a maximum dose of 2.5 mg twice daily depending upon clinical response and tolerability.

Use in children: No information is yet available on the use of Ramipril in children.

Acute Overdose

The most common signs and symptoms observed are those caused by electrolyte depletion (hypokalemia, hypochloremia, hyponatremia) and dehydration resulting from excessive diuresis. Rarely, autoimmune hemolytic anemia and other hypersensitivity reactions may complicate the picture.

In the event of over dosage, symptomatic and supportive measures should be employed. Emesis should be induced or gastric lavage performed. Correct dehydration, electrolyte imbalance, hepatic coma and hypotension by established procedures. Hemodialysis can be used successfully to treat severe intoxication.

Limited data are available regarding overdose in humans. The most likely manifestation of overdose would be hypotension and tachycardia; bradycardia could occur from parasympathetic (vagal) stimulation. Supportive treatment should include repletion of the intravascular volume. Neither Losartan nor the active metabolite can be removed by hemodialysis.

Limited data on human overdosage are available. The most likely clinical manifestations would be symptoms attributable to hypotension. Because the hypotensive effect of Ramipril is achieved through vasodilation and effective hypovolemia, it is reasonable to treat Ramipril overdosage by infusion of normal saline solution.

Storage Condition

Store between 15-30°C. Protect from light, moisture and freezing.

Store between 15-30°C

Store at cool & dry place, protect from light and moisture.

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