1. Introduction
Nifedipine is a calcium channel blocker used to treat hypertension (high blood pressure) and angina (chest pain). It works by relaxing the blood vessels, allowing blood to flow more easily, and reducing the heart’s workload. Nifedipine is available in immediate-release and extended-release formulations, with specific uses tailored to different cardiovascular conditions.
2. Indications
- Hypertension (high blood pressure)
- Chronic stable angina (chest pain)
- Vasospastic angina (Prinzmetal’s angina)
- Raynaud’s phenomenon (off-label use)
3. Dosage
Adults:
- Hypertension:
- Extended-release: 30–60 mg once daily; maximum 90–120 mg/day.
- Chronic stable angina/Vasospastic angina:
- Extended-release: 30–60 mg once daily; adjust based on response (maximum: 120 mg/day).
Immediate-release formulations are generally not recommended for hypertension or chronic angina due to an increased risk of adverse cardiovascular events. They are typically used for acute episodes under specific medical supervision.
Children:
- Not commonly used; safety and efficacy in children have not been established for most conditions.
Elderly:
- Start with the lowest dose due to increased sensitivity to hypotensive effects.
4. Administration
- Extended-release tablets should be taken orally, swallowed whole with water.
- Do not chew, crush, or break the tablets to maintain their extended-release properties.
- Can be taken with or without food; take at the same time each day for consistent effects.
5. Forms Available
- Extended-release tablets: 30 mg, 60 mg, 90 mg
- Immediate-release capsules: 10 mg, 20 mg (limited use)
6. Side Effects
6.1 Common Side Effects:
- Headache
- Flushing
- Dizziness
- Swelling of the ankles or feet (peripheral oedema)
6.2 Less Common Side Effects:
- Nausea
- Fatigue
- Palpitations
6.3 Rare but Serious Side Effects:
- Hypotension (low blood pressure)
- Severe allergic reactions (e.g., angioedema)
- Myocardial infarction (especially with inappropriate use of immediate-release formulations)
7. Warnings
- Hypotension: Nifedipine can cause a significant drop in blood pressure, especially in the elderly or in patients initiating therapy.
- Immediate-Release Forms: Immediate-release Nifedipine should not be used for long-term control of hypertension due to the risk of rapid blood pressure reduction and adverse cardiovascular events.
- Heart Failure: Use cautiously in patients with heart failure or significant left ventricular dysfunction.
8. Precautions
- Use cautiously in patients with severe hepatic impairment, as Nifedipine is extensively metabolised by the liver.
- Avoid abrupt discontinuation, which may exacerbate angina or lead to rebound hypertension.
- Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
9. Interactions
- CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): Increased levels of Nifedipine, leading to a higher risk of side effects.
- Beta-blockers: Combined use may increase the risk of heart failure or severe hypotension.
- Grapefruit juice: Increases Nifedipine levels; avoid concurrent use.
- Antihypertensives: Additive hypotensive effects.
10. Monitoring Parameters
- Monitor blood pressure and heart rate regularly, especially during dose adjustments.
- Assess for signs of peripheral oedema.
- Monitor for symptoms of angina relief and exercise tolerance.
11. Use in Children
- Not typically recommended for children. Consult a specialist for potential off-label use.
12. Use in Pregnancy
- Classified as Category C. Use only if the potential benefits justify the risks. Often used for managing hypertensive disorders during pregnancy under medical supervision.
13. Use in Elderly
- Start with a lower dose due to increased sensitivity to hypotension. Monitor closely for dizziness and falls.
14. Use in Kidney Disease
- No specific dosage adjustment required for renal impairment, as Nifedipine is not primarily excreted by the kidneys.
15. Use in Liver Disease
- Use cautiously in patients with liver disease; dose adjustments may be necessary due to altered metabolism.
16. Patient Counselling Points
- Take Nifedipine at the same time each day, and do not crush or chew the tablets.
- Avoid consuming grapefruit juice while taking Nifedipine.
- Report any unusual symptoms, such as swelling of the feet, persistent headache, or signs of an allergic reaction.
- Stand up slowly from sitting or lying positions to reduce dizziness or lightheadedness.
- Do not stop taking Nifedipine abruptly without consulting your doctor, as this may worsen your condition.
17. Table of Brand Names, Manufacturer, and Prices in USD
Brand Name | Manufacturer | Strength/Dosage Form | Price (USD) |
---|---|---|---|
Adalat CC | Bayer | 30 mg Extended-Release Tablet | $25 (30 tablets) |
Procardia XL | Pfizer | 60 mg Extended-Release Tablet | $35 (30 tablets) |
Generic Nifedipine | Various | 30 mg Extended-Release Tablet | $15 (30 tablets) |
18. 15 FAQs (Frequently Asked Questions)
1. What is Nifedipine used for?
Nifedipine is used to treat high blood pressure (hypertension) and angina (chest pain).
2. How does Nifedipine work?
It is a calcium channel blocker that relaxes blood vessels, improving blood flow and reducing heart workload.
3. What is the usual dose of Nifedipine?
The typical dose for hypertension is 30–60 mg once daily in an extended-release formulation.
4. Can Nifedipine cause swelling?
Yes, peripheral oedema (swelling of the ankles or feet) is a common side effect.
5. Can Nifedipine be taken during pregnancy?
It can be used during pregnancy for specific conditions, but only under medical supervision.
6. Can I drink grapefruit juice while taking Nifedipine?
No, grapefruit juice can increase Nifedipine levels, leading to more side effects.
7. How long does it take for Nifedipine to start working?
It starts working within 30 minutes to 2 hours, but full effects may take longer depending on the condition being treated.
8. Can Nifedipine be used for Raynaud’s phenomenon?
Yes, it is sometimes used off-label for Raynaud’s phenomenon to improve blood flow to the extremities.
9. What should I do if I miss a dose?
Take it as soon as you remember, unless it is close to the next dose. Do not double the dose.
10. Can Nifedipine cause low blood pressure?
Yes, it can cause hypotension, especially when starting treatment or increasing the dose.
11. Is Nifedipine addictive?
No, Nifedipine is not addictive, but it should not be stopped abruptly.
12. How should Nifedipine be stored?
Store at room temperature, away from moisture and heat.
13. Can Nifedipine be used in heart failure?
Use cautiously in patients with heart failure, as it may worsen symptoms in some cases.
14. Can Nifedipine cause headaches?
Yes, headaches are a common side effect, particularly when starting treatment.
15. Do I need a prescription for Nifedipine?
Yes, Nifedipine is a prescription-only medication.