Usage
- Benidipine + Chlorthalidone is prescribed for the management of hypertension (high blood pressure) and angina pectoris (chest pain due to reduced blood flow to the heart).
- Pharmacological classification: This combination drug includes a calcium channel blocker (Benidipine) and a thiazide-like diuretic (Chlorthalidone).
- Mechanism of action: Benidipine relaxes blood vessels by blocking calcium channels, while Chlorthalidone reduces blood volume by increasing the excretion of water and sodium. This combined action lowers blood pressure and improves blood flow to the heart.
Alternate Names
- No widely recognized alternate names exist for the combination itself. The individual components have other names, such as Hygroton or Thalitone for Chlorthalidone.
- Brand Names: Benitowa CH, Benidin CH, Benina C.
How It Works
- Pharmacodynamics: Benidipine causes vasodilation by blocking calcium channels in vascular smooth muscle. Chlorthalidone inhibits sodium reabsorption in the distal convoluted tubule of the nephron, leading to increased water excretion, reduced blood volume, and lower blood pressure.
- Pharmacokinetics: Benidipine is well-absorbed orally and extensively metabolized by the liver. Chlorthalidone is also absorbed well orally and primarily eliminated unchanged by the kidneys.
- Mode of Action: Benidipine primarily targets L-type, T-type, and N-type calcium channels, leading to vasodilation. Chlorthalidone inhibits the sodium-chloride cotransporter in the distal convoluted tubule, increasing sodium and water excretion.
- Elimination pathways: Benidipine is mostly eliminated through hepatic metabolism (CYP3A4 involvement), while Chlorthalidone is mainly excreted unchanged via the kidneys.
Dosage
Standard Dosage
Adults:
- Typical starting dosage: Benidipine 4 mg + Chlorthalidone 12.5 mg once daily, usually taken in the morning with food. The dosage may be adjusted as needed based on individual patient response and tolerance.
- Maximum Dosage: Up to Benidipine 8mg + Chlorthalidone 25mg. Some patients may need 150–200 mg of Chlorthalidone.
Children:
- Use in children under 18 is generally not recommended due to limited safety and efficacy data. In specific situations, pediatric dosing may be calculated based on weight (0.3 mg/kg/day initially, titrated up to 2 mg/kg/day, not to exceed 50 mg per day) under close monitoring by a physician.
Special Cases:
- Elderly Patients: Start with a lower dose (e.g., Benidipine 4 mg + Chlorthalidone 6.25 mg) and titrate cautiously due to increased sensitivity to side effects and potential for age-related decline in renal function.
- Patients with Renal Impairment: Dosage adjustments are necessary in patients with moderate to severe renal impairment as Chlorthalidone is primarily eliminated by the kidneys.
- Patients with Hepatic Dysfunction: Start with a lower dose of Benidipine due to its hepatic metabolism and adjust according to patient response. Close monitoring is essential.
- Patients with Comorbid Conditions: Careful monitoring is required for patients with diabetes, gout, heart failure, or other relevant conditions, and dosage adjustments may be necessary.
Clinical Use Cases
The Benidipine + Chlorthalidone combination isn’t typically used in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations.
Dosage Adjustments
- Dosage adjustments should be individualized based on patient response, renal/hepatic function, and other factors.
Side Effects
Common Side Effects:
- Dizziness, headache, fatigue, nausea, hypotension, electrolyte imbalances (hypokalemia, hyponatremia), increased urination, muscle cramps, and peripheral edema.
Rare but Serious Side Effects:
- Severe hypotension, syncope, hypokalemia, hyponatremia, and allergic reactions.
Long-Term Effects:
- Electrolyte imbalances, gout exacerbation, and new-onset or worsening of diabetes.
Adverse Drug Reactions (ADR):
- Angioedema, Stevens-Johnson syndrome (rare).
Contraindications
- Hypersensitivity to Benidipine, Chlorthalidone, or sulfonamides.
- Anuria (kidney failure resulting in no urine output).
- Severe hypotension.
Drug Interactions
- Other antihypertensives (additive hypotensive effects).
- NSAIDs (reduced antihypertensive efficacy, increased risk of renal impairment).
- Lithium (increased lithium levels and toxicity).
- Digoxin (increased digoxin levels).
- Corticosteroids (increased risk of hypokalemia).
- Alcohol (increased risk of hypotension).
- CYP3A4 inhibitors (like ketoconazole, erythromycin) may increase Benidipine levels.
- CYP3A4 inducers (like rifampicin) may reduce the effectiveness of Benidipine.
Pregnancy and Breastfeeding
- Pregnancy: Not recommended, particularly during the second and third trimesters, due to the potential for fetal harm (Chlorthalidone).
- Breastfeeding: Chlorthalidone is excreted in breast milk and can suppress lactation. Benidipine may also enter breast milk; hence, the combination should be used with caution during breastfeeding.
Drug Profile Summary
- Mechanism of Action: Benidipine: Calcium channel blocker (vasodilation); Chlorthalidone: Thiazide-like diuretic (reduces blood volume).
- Side Effects: Dizziness, headache, fatigue, nausea, hypotension, electrolyte imbalances.
- Contraindications: Hypersensitivity, anuria, severe hypotension.
- Drug Interactions: Other antihypertensives, NSAIDs, lithium, digoxin, corticosteroids, alcohol, CYP3A4 inhibitors/inducers.
- Pregnancy & Breastfeeding: Not recommended during pregnancy, use with caution during breastfeeding.
- Dosage: Individualized based on patient characteristics and response.
- Monitoring Parameters: Blood pressure, electrolyte levels, renal function, blood glucose, cholesterol.
Popular Combinations
While Benidipine and Chlorthalidone are often used together, specific popular combinations with other drugs depend on individual patient needs and characteristics and should be made under professional medical supervision.
Precautions
- Monitor electrolytes, renal function, blood glucose, and cholesterol.
- Patients with kidney/liver disease, gout, diabetes, or heart failure require close monitoring.
- Caution patients about dizziness and orthostatic hypotension.
- Advise patients to avoid alcohol.
- Avoid abrupt discontinuation.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Benidipine + Chlorthalidone?
A: The dosage is individualized based on patient-specific factors, but a typical starting dose is Benidipine 4 mg + Chlorthalidone 12.5 mg once daily.
Q2: Can Benidipine + Chlorthalidone be used during pregnancy?
A: It’s generally not recommended during pregnancy, especially in the second and third trimesters, due to potential risks to the fetus.
Q3: Is it safe to take Benidipine + Chlorthalidone while breastfeeding?
A: Chlorthalidone can be excreted in breast milk and may suppress lactation. Caution is advised. Discuss with the physician to weigh the benefits against the risks or consider alternatives.
Q4: What are the common side effects of this combination?
A: Dizziness, headache, fatigue, nausea, hypotension, electrolyte imbalances, increased urination.
Q5: What should I do if I miss a dose?
A: Take the missed dose as soon as you remember, unless it is close to the next scheduled dose. Do not double the dose.
Q6: Can I drink alcohol while taking this medication?
A: Alcohol may increase the risk of hypotension and other side effects. It’s best to avoid or limit alcohol consumption.
Q7: Does this medication interact with other drugs I’m taking?
A: Yes, it can interact with various medications, including other antihypertensives, NSAIDs, and lithium. Always inform your doctor about all medications you are currently taking.
Q8: What should I monitor while taking Benidipine + Chlorthalidone?
A: Regular monitoring of blood pressure, electrolyte levels, renal function, and blood glucose is important.
Q9: Are there any specific precautions for elderly patients?
A: Elderly patients may be more sensitive to side effects. Lower starting doses and careful titration are usually recommended.
Q10: Can this medication be used in patients with kidney or liver problems?
A: Dosage adjustments may be required in patients with renal or hepatic dysfunction. Close monitoring is essential.
