Nifedipine

What Does Nifedipine Do?

Nifedipine is a calcium channel blocker used to treat high blood pressure and angina by relaxing and widening blood vessels. This helps improve blood flow and lower blood pressure. Additionally, it is used off-label for Raynaud's phenomenon and migraine prevention. 

How Does Nifedipine Work? (the complicated stuff)

Nifedipine works by blocking specific calcium channels called L-type voltage-gated calcium channels in the cells of the heart and blood vessels. These channels normally allow calcium ions to flow into the cells when they are stimulated, which is important for muscle contraction. By preventing calcium from entering the cells, nifedipine reduces the amount of calcium inside the smooth muscle cells of blood vessels. This leads to the relaxation of these muscles, causing the blood vessels to widen (vasodilation). As a result, blood flow improves, and the resistance against blood flow (known as peripheral resistance) decreases, which lowers both systolic and diastolic blood pressure.

Drug Type and Category of Nifedipine

Nifedipine belongs to a class of medications called dihydropyridine calcium channel blockers, which primarily affect blood vessels. These medications work by blocking calcium from entering the muscle cells of the heart and blood vessels, leading to relaxation and dilation of blood vessels.

What dosage of Nifedipine should you be taking?

NICE Guidelines ¹

Hypertension:

• Initial Dose: Start with 30 mg to 60 mg of extended-release nifedipine taken once daily.
• Maintenance Dose: Adjust the dose as needed, typically ranging from 30 mg to 90 mg once daily.
• Maximum Dose: Do not exceed 120 mg per day.

Angina:

• Initial Dose: Begin with 30 mg to 60 mg of extended-release nifedipine taken once daily.
• Maintenance Dose: Adjust the dose as needed, typically ranging from 30 mg to 90 mg once daily.
• Maximum Dose: Do not exceed 120 mg per day.

It's important to note that NICE recommends using nifedipine only when other treatments are unsuitable. Additionally, NICE advises against using immediate-release nifedipine for hypertension due to safety concerns.

What are the side-effects of Nifedipine?

Common Side Effects:

1. Swelling (Oedema): Nifedipine can cause swelling in the legs, ankles, or feet due to fluid retention. This is a big issue and can be very problematic for people. Speak to your GP if you notice this. 
2. Headache: Some people may experience headaches, particularly when starting treatment or increasing the dose.
3. Flushing: A common side effect, flushing or redness of the skin, especially in the face, can occur due to the dilating effect on blood vessels.
4. Dizziness or Lightheadedness: This may happen when standing up quickly, as nifedipine can cause a drop in blood pressure (orthostatic hypotension).
5. Palpitations: Some individuals may feel a rapid or irregular heartbeat (palpitations) while on nifedipine.
6. Fatigue: Feeling unusually tired or weak can also be a side effect of nifedipine.
7. Nausea: Gastrointestinal discomfort like nausea may occur, especially in the early stages of treatment.

Serious Side Effects:

1. Severe Hypotension: Nifedipine can cause significant low blood pressure, particularly if the dose is too high or if a person is already taking other blood pressure-lowering medications.
2. Heart Attack: In rare cases, especially with immediate-release nifedipine, there may be an increased risk of heart attack due to reflex tachycardia (a rapid heartbeat in response to low blood pressure).
3. Worsening of Angina: For some individuals, nifedipine can cause a worsening of angina (chest pain), particularly when the drug causes rapid drops in blood pressure.
4. Gingival Hyperplasia: An overgrowth of gum tissue around the teeth can occur in some patients.
5. Severe Allergic Reactions: Although rare, nifedipine can cause severe allergic reactions, including swelling of the face, lips, or tongue, difficulty breathing, or skin rashes.
6. Liver Dysfunction: Nifedipine can affect liver function, leading to elevated liver enzymes. Liver problems can manifest as yellowing of the skin or eyes (jaundice).

Other Considerations:

• Pregnancy and Breastfeeding: Nifedipine should be used with caution in pregnancy, especially during the first trimester, and should only be prescribed if the benefits outweigh the risks. It is generally considered safe for use during breastfeeding, but it should be used under medical supervision.

Interactions

1. Medications for High Blood Pressure

• ACE Inhibitors (e.g., enalapril, lisinopril)
• Angiotensin II Receptor Blockers (ARBs) (e.g., losartan, valsartan)
• Beta-blockers (e.g., atenolol, metoprolol)
• Diuretics (e.g., furosemide, hydrochlorothiazide)

Interaction: Using nifedipine in combination with these blood pressure-lowering medications can lead to excessive lowering of blood pressure, resulting in symptoms like dizziness, fainting, or fainting upon standing (orthostatic hypotension). The combination may require careful monitoring of blood pressure.

2. Other Calcium Channel Blockers (e.g., verapamil, diltiazem)

• Interaction: Taking nifedipine with other calcium channel blockers can cause a significant drop in heart rate (bradycardia), severe hypotension, and an increased risk of heart failure. This combination should generally be avoided or used under close supervision.

3. Cyclosporine

• Interaction: Nifedipine can increase the levels of cyclosporine (an immunosuppressant drug) in the blood, increasing the risk of toxicity. This combination requires careful monitoring of cyclosporine levels.

4. Grapefruit Juice

• Interaction: Grapefruit juice can increase the absorption of nifedipine, which may lead to higher blood levels of the drug, increasing the risk of side effects like low blood pressure, swelling, or dizziness. It’s advised to avoid grapefruit juice or consume it in moderation while on nifedipine.

5. Rifampin

• Interaction: Rifampin, an antibiotic used to treat tuberculosis, can reduce the effectiveness of nifedipine by increasing the metabolism of the drug, leading to lower blood levels of nifedipine. This may reduce its ability to control blood pressure or angina.

6. Antifungal Medications (e.g., ketoconazole, itraconazole)

• Interaction: These antifungals can increase nifedipine levels in the blood by inhibiting its metabolism. This could increase the risk of side effects such as dizziness, swelling, or even heart problems.

7. HIV Protease Inhibitors (e.g., ritonavir, lopinavir)

• Interaction: Like antifungals, HIV protease inhibitors can increase nifedipine levels in the blood. This can increase the risk of side effects such as low blood pressure and fluid retention.

8. St. John’s Wort

• Interaction: St. John’s Wort, a commonly used herbal supplement for depression, can reduce the effectiveness of nifedipine by increasing its metabolism. This could result in inadequate blood pressure control or angina relief.

9. Lithium

• Interaction: Nifedipine may increase lithium levels in the blood, increasing the risk of lithium toxicity, which can cause symptoms like tremors, nausea, and confusion. If you are taking lithium, your doctor may monitor your blood levels more closely.

10. Alcohol

• Interaction: Alcohol can enhance the blood pressure-lowering effects of nifedipine, increasing the risk of hypotension and dizziness. It is advisable to limit alcohol consumption while on nifedipine.

11. Antacids

• Interaction: Some antacids (especially those containing aluminum or magnesium) can interfere with the absorption of nifedipine, reducing its effectiveness. To avoid this interaction, it’s generally recommended to take nifedipine at least 2 hours before or after taking an antacid.

Natural Alternatives to Nifedipine

Garlic

• How it Helps: Garlic has been shown to have blood pressure-lowering effects. It contains allicin, which can help relax blood vessels and improve blood flow. Regular consumption of garlic may help reduce both systolic and diastolic blood pressure ?2;.
• Use: You can consume raw garlic, take garlic supplements, or include garlic in your cooking.

Hibiscus Tea

• How it Helps: Hibiscus tea has been shown to lower blood pressure, especially in people with mild to moderate hypertension. The antioxidants in hibiscus help to improve blood vessel health and circulation ?2;.
• Use: Drinking 2-3 cups of hibiscus tea daily can be effective in reducing blood pressure.

Omega-3 Fatty Acids

• How it Helps: Found in fish oil and flaxseeds, omega-3 fatty acids have been shown to help lower blood pressure by reducing inflammation and improving blood vessel function. They also help reduce triglyceride levels and can support heart health ?3;.
• Use: Omega-3s can be consumed through fatty fish like salmon, mackerel, and sardines or through supplements like fish oil or algae oil.

Beetroot Juice

• How it Helps: Beetroot is rich in nitrates, which can help dilate blood vessels and improve blood flow, leading to lower blood pressure. Studies have shown that drinking beetroot juice can reduce systolic blood pressure significantly ?.
• Use: Drinking fresh beetroot juice or including it in your diet can help lower blood pressure. It is recommended to consume about 250 ml per day for optimal effects.

Coenzyme Q10 (CoQ10)

• How it Helps: CoQ10 is an antioxidant that helps improve heart health. It has been found to lower blood pressure by improving vascular function and reducing oxidative stress ?.
• Use: CoQ10 can be taken as a supplement, typically in doses ranging from 100 mg to 200 mg per day.

Cayenne Pepper (Capsaicin)

• How it Helps: Cayenne pepper contains capsaicin, which has been shown to improve circulation and relax blood vessels, potentially lowering blood pressure. It also supports healthy metabolism ?.
• Use: Adding cayenne pepper to food or consuming it in capsule form can help maintain heart health and support circulation.

Olive Leaf Extract

• How it Helps: Olive leaf extract has antioxidant and anti-inflammatory properties. It has been shown to help reduce blood pressure by improving blood vessel function and reducing oxidative stress ?.
• Use: Olive leaf extract is available in supplement form and can be taken daily to support heart health.

Magnesium

• How it Helps: Magnesium is a key mineral involved in muscle and nerve function. It helps regulate blood pressure by improving blood vessel relaxation and reducing vascular resistance ?.
• Use: Magnesium-rich foods include leafy greens, nuts, seeds, and whole grains. Magnesium supplements can also be used, with a typical dose being 300-400 mg per day.

L-citrulline

• How it Helps: L-citrulline is an amino acid that is converted into L-arginine in the body, which in turn increases nitric oxide production. Nitric oxide helps relax and dilate blood vessels, improving blood flow and reducing blood pressure ?.
• Use: L-citrulline is available in supplement form, and typical doses range from 3 to 6 grams per day.

Ashwagandha

• How it Helps: Ashwagandha, an adaptogenic herb, has been shown to lower blood pressure, particularly in individuals with stress-induced hypertension. It helps reduce cortisol levels and supports overall cardiovascular health ?1;?.
• Use: Ashwagandha can be taken in powder or capsule form, typically in doses ranging from 300 mg to 600 mg daily.

Turmeric (Curcumin)

• How it Helps: Curcumin, the active compound in turmeric, has powerful anti-inflammatory and antioxidant properties that can help reduce blood pressure and improve heart health by improving blood vessel function ?1;?1;.
• Use: Turmeric can be added to food, taken as a supplement (typically 500 mg to 2,000 mg per day), or consumed as turmeric tea.

Interesting facts about Nifedipine

Nifedipine was first approved for medical use in the 1970s as a treatment for high blood pressure (hypertension) and angina (chest pain). It works by relaxing blood vessels, which helps lower blood pressure and improves blood flow to the heart.

Nifedipine is available in immediate-release and extended-release formulations. The immediate-release form works quickly to relieve symptoms but can cause more pronounced side effects, such as a sudden drop in blood pressure. The extended-release form is designed for longer-term control and provides more consistent blood pressure management.

Nifedipine is sometimes used off-label as a treatment for preterm labor. It works by relaxing the muscles of the uterus, which can help delay premature birth. This use is typically for short-term management and requires careful monitoring by healthcare providers.

Disclaimer

This article is generated for informational purposes only. It was created in January 2025. Medications and medical guidance can change over time. Therefore, it is essential to consult with your general practitioner or healthcare provider before making any decisions regarding medications or treatment plans. Your GP can provide personalised advice based on your specific health needs and conditions.

References

1. https://bnfc.nice.org.uk/drugs/nifedipine/
2. Ried, K., et al. (2010). Garlic lowers blood pressure in hypertensive individuals. Journal of Clinical Hypertension.
3. Hooper, L., et al. (2008). Omega-3 fatty acids and blood pressure. Cochrane Database of Systematic Reviews.
4. Siervo, M., et al. (2013). Beetroot juice and blood pressure. Hypertension Journal.
5. Mortensen, S. A., et al. (2001). Coenzyme Q10 in cardiovascular disease. Journal of Cardiovascular Pharmacology.
6. Zeng, J., et al. (2015). Capsaicin and cardiovascular health. International Journal of Cardiology.
7. Pérez-Sánchez, A., et al. (2017). Olive leaf extract and blood pressure. Journal of Nutritional Biochemistry.
8. Rosanoff, A., et al. (2012). Magnesium intake and hypertension. American Journal of Clinical Nutrition.
9. Schwedhelm, E., et al. (2015). L-citrulline and nitric oxide. Vascular Pharmacology.
10. Choudhary, D., et al. (2017). Ashwagandha and hypertension. Phytotherapy Research.
11. Sahebkar, A., et al. (2016). Turmeric and cardiovascular health. Journal of Hypertension.