ARBITEL AM 40/5MG TABLET

Indications

• Hypertension
• Angina

Dosage

Children: Children 1 month to 11 years: Initially 100–200 micrograms/kg once daily; increased if necessary at intervals of 1–2 weeks up to a maximum of 5 mg once daily.

Adults: Initially, 5 mg once daily, increased if necessary to a maximum of 10 mg once daily.

Mechanism of action

Amlodipine inhibits the influx of calcium ions into vascular smooth muscle and cardiac muscle cells, leading to vasodilation and decreased myocardial oxygen demand.

Pharmacodynamics

Amlodipine causes a reduction in systemic vascular resistance and arterial pressure, resulting in decreased workload on the heart. It has a long duration of action due to its slow onset and prolonged effects.

Pharmacokinetics

Amlodipine is well absorbed orally, with peak plasma concentrations occurring 6-12 hours after administration. It has a half-life of approximately 30-50 hours, allowing for once-daily dosing. It is extensively metabolized in the liver and excreted primarily in the urine.

Contra-indications

• Cardiogenic shock
• Aortic stenosis

Adverse effects

• Asthenia
• Constipation
• Diarrhoea
• Drowsiness
• Dyspnoea
• Gastrointestinal disturbances

Interactions

• Grapefruit juice (severe increase in exposure)
• Enzalutamide (moderate decrease in exposure)
• Apalutamide (moderate decrease in exposure)
• Dronedarone (moderate increase in exposure)
• Antifungals (azoles) (moderate increase in exposure)
• Miconazole (moderate increase in exposure)
• Cobicistat (moderate increase in exposure)
• Crizotinib (moderate increase in exposure)
• Dabrafenib (moderate decrease in exposure)
• Idelalisib (moderate increase in exposure)

Precautions

• Caution in hepatic impairment (risk of increased exposure)
• Monitor for sudden withdrawal effects, which may exacerbate myocardial ischaemia

Pregnancy

Manufacturer advises caution due to limited data on safety.

Breast-feeding

Manufacturer advises to avoid; no information available.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Amlodipine 5mg/5ml oral solution (sugar-free)
• Amlodipine 10mg/5ml oral solution (sugar-free)
• Amlodipine 5 mg tablets
• Amlodipine 10 mg tablets

Indications

• Hypertension
• Heart failure
• Cardiovascular risk reduction

Dosage

Children: Refer to BNF for Children for appropriate paediatric dosing.

Adults: Refer to specific guidelines for dosing, typically starting from 40 mg once daily, with possible titration based on clinical response.

Mechanism of action

Telmisartan works by selectively blocking the binding of angiotensin II to the angiotensin type 1 (AT1) receptor. This blockade prevents the vasoconstrictive and aldosterone-secreting effects of angiotensin II, leading to reduced blood pressure and decreased systemic vascular resistance. Telmisartan also activates the angiotensin type 2 (AT2) receptor, which promotes vasodilation and has beneficial effects on cardiovascular health.

Pharmacodynamics

Telmisartan has a long duration of action, with antihypertensive effects lasting up to 24 hours after a single dose. It lowers blood pressure through both arterial dilation and inhibition of the renin-angiotensin-aldosterone system (RAAS). Telmisartan may also improve insulin sensitivity and has a favorable impact on lipid profiles.

Pharmacokinetics

Telmisartan is well absorbed after oral administration, with peak plasma concentrations occurring within 0.5 to 1 hour. It has a bioavailability of approximately 50%, and its effects are dose-dependent. Telmisartan is highly protein-bound (approximately 99.5%) and is metabolized primarily in the liver, with less than 1% of the dose being excreted unchanged in urine. The elimination half-life is about 24 hours, allowing for once-daily dosing.

Contra-indications

• Hypersensitivity to telmisartan or any excipients
• Severe hepatic impairment
• Pregnancy
• Severe renal impairment or patients on dialysis

Adverse effects

• Dizziness
• Fatigue
• Headache
• Abdominal pain
• Nausea
• Hypotension
• Hyperkalemia
• Renal impairment

Interactions

• Other antihypertensives may increase the hypotensive effect
• Potassium supplements or potassium-sparing diuretics may increase the risk of hyperkalemia
• Nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce the antihypertensive effect
• Lithium levels may increase when combined with telmisartan

Precautions

• Monitor renal function periodically
• Use with caution in patients with renal artery stenosis
• Caution in patients with a history of angioedema
• Assess potassium levels in patients at risk for hyperkalemia

Pregnancy

Telmisartan is contraindicated in pregnancy due to potential harm to the fetus, particularly in the second and third trimesters.

Breast-feeding

It is not known whether telmisartan is excreted in human milk; caution is advised when administering to nursing mothers.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Tablets: 20 mg, 40 mg, 80 mg

Mechanism of action

**Mechanism of action on blood pressure** Amlodipine is considered a peripheral arterial vasodilator that exerts its action directly on vascular smooth muscle to lead to a reduction in peripheral vascular resistance, causing a decrease in blood pressure. Amlodipine is a dihydropyridine calcium antagonist (calcium ion antagonist or slow-channel blocker) that inhibits the influx of calcium ions into both vascular smooth muscle and cardiac muscle. Experimental studies imply that amlodipine binds to both _dihydropyridine_ and _nondihydropyridine_ binding sites, located on cell membranes. The contraction of cardiac muscle and vascular smooth muscle are dependent on the movement of extracellular calcium ions into these cells by specific ion channels. Amlodipine blocks calcium ion influx across cell membranes with selectivity. A stronger effect of amlodipine is exerted on vascular smooth muscle cells than on cardiac muscle cells. Direct actions of amlodipine on vascular smooth muscle result in reduced blood pressure. **Mechanism of action in angina** The exact mechanism by which amlodipine relieves the symptoms of angina have not been fully elucidated to this date, however, the mechanism of action is likely twofold: Amlodipine has a dilating effect on peripheral arterioles, reducing the total peripheral resistance (afterload) against which the cardiac muscle functions. Since the heart rate remains stable during amlodipine administration, the reduced work of the heart reduces both myocardial energy use and oxygen requirements. Dilatation of the main coronary arteries and coronary arterioles, both in healthy and ischemic areas, is another possible mechanism of amlodipine reduction of blood pressure. The dilatation causes an increase in myocardial oxygen delivery in patients experiencing coronary artery spasm (Prinzmetal's or variant angina) and reduces coronary vasoconstriction caused by smoking. Amlodipine is a dihydropyridine calcium antagonist (calcium ion antagonist or slow-channel blocker) that inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle. Experimental data suggest that amlodipine binds to both dihydropyridine and nondihydropyridine binding sites. The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. Amlodipine inhibits calcium ion influx across cell membranes selectively, with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. Negative inotropic effects can be detected in vitro but such effects have not been seen in intact animals at therapeutic doses. Serum calcium concentration is not affected by amlodipine. Within the physiologic pH range, amlodipine is an ionized compound (pKa=8.6), and its kinetic interaction with the calcium channel receptor is characterized by a gradual rate of association and dissociation with the receptor binding site, resulting in a gradual onset of effect. Recent studies have suggested that cytokines are capable of modifying cardiovascular function and that drugs used in the treatment of heart failure have various modulating properties on the production of cytokines. More recently, we have found that ouabain induces the production of cytokines. This study was performed to examine the effects of calcium channel blockers on the production of cytokines induced by a cardiac glycoside. Human peripheral blood mononuclear cells (PBMC) were obtained from healthy volunteers. PBMC were cultured in 0.1, 1, 10, and 30 umol/L amlodipine, diltiazem, and nifedipine in presence of 1 umol/L ouabain. After 24 hr of incubation, IL-1alpha, IL-1beta, IL-6, and TNF-alpha were measured in the culture supernatants by enzyme-linked immunosorbent assay. Ouabain induced the production of IL-1alpha, IL-1beta and IL-6, but not of TNF-alpha. Induction of IL-1beta was most prominent. The production of IL-1alpha, and IL-6 wa

Pharmacodynamics

**General pharmacodynamic effects** Amlodipine has a strong affinity for cell membranes, modulating calcium influx by inhibiting selected membrane calcium channels. This drug's unique binding properties allow for its long-acting action and less frequent dosing regimen,. **Hemodynamic effects** After the administration of therapeutic doses of amlodipine to patients diagnosed with hypertension, amlodipine causes vasodilation, which results in a reduction of supine and standing blood pressure. During these blood pressure reductions, there are no clinically significant changes in heart rate or plasma catecholamine levels with long-term use. Acute intravenous administration of amlodipine reduces arterial blood pressure and increases heart rate in patients with chronic stable angina, however, chronic oral administration of amlodipine in clinical studies did not cause clinically significant alterations in heart rate or blood pressures in patients diagnosed with angina and normal blood pressure. With long-term, once daily oral administration, antihypertensive effectiveness is maintained for at least 24 hours. **Electrophysiologic effects** Amlodipine does not change sinoatrial (SA) nodal function or atrioventricular (AV) conduction in animals or humans. In patients who were diagnosed with chronic stable angina, the intravenous administration of 10 mg of amlodipine did not cause clinically significant alterations A-H and H-V conduction and sinus node recovery time after cardiac pacing. Patients administered amlodipine with concomitant beta-blockers produced similar results. In clinical trials in which amlodipine was given in combination with beta-blockers to patients diagnosed with hypertension or angina, no adverse effects on electrocardiographic parameters were noted. In clinical studies comprised of angina patients alone, amlodipine did not change electrocardiographic intervals or produce high degrees of AV block. **Effects on angina** Amlodipine relieves the symptoms of chest pain associated with angina. In patients diagnosed with angina, daily administration of a single amlodipine dose increases total exercise time, the time to angina onset, and the time to 1 mm ST-segment depression on ECG studies, decreases anginal attack frequency, and decreases the requirement for nitroglycerin tablets.