Overview of Plendil

Property	Description
Active Ingredient	Felodipine
Form	Extended-release tablets (Oral)
Pharmacological Class	Calcium Channel Blocker (Dihydropyridine)
Common Purpose	Antihypertensive agent
Origin	Synthetic

What Type of Medicine is Plendil and Its Purpose?

Plendil is a well-recognized brand name for a synthetic, prescription-only medicine containing the active ingredient Felodipine, which is chemically classified as a second-generation dihydropyridine. This substance belongs to the broader pharmacological class of Calcium Channel Blockers (CCBs), a category clinically recognized for its effects on vascular tone. The general therapeutic purpose of Plendil is its use as an antihypertensive agent for the long-term management of high blood pressure, and it may also be used in the management of chronic stable angina.

The medication's effect is driven by its ability to cause targeted relaxation and widening of the systemic arteries. Drugs in this class are used to achieve substantial, sustained reductions in arterial pressure.

Composition and Formulation: Extended-Release Felodipine

The medication is a single-ingredient product supplied exclusively as extended-release tablets for oral administration. This specialized extended-release (ER) design, which ensures a gradual and consistent release of the active substance over 24 hours, is a key differentiating feature of the Plendil formulation.

This sustained delivery profile is valued in clinical practice because it avoids the sharp fluctuations in drug concentration often associated with standard immediate-release forms. The consistent delivery of Felodipine is intended to provide stable, round-the-clock control of blood pressure, a requirement for patients managing chronic hypertension.

Regulatory References

What side effects are possible with Plendil?

Possible Side Effects and Safety Information

The safety profile of Plendil (Felodipine) is officially classified by regulatory authorities based on the frequency and system-organ class of reported reactions in clinical data. Most documented adverse reactions are related to the medicine’s vasodilatory effects, which are typically dose-dependent and more likely to manifest at the start of treatment or following a dose increase.

Frequency-Classified Adverse Reactions

The most commonly reported effect, classified as Very Common in regulatory documents, is peripheral oedema (swelling, often in the ankles). Reactions classified as Common include headache and flushing (redness of the face/neck). Less frequent effects, classified as Uncommon, include fatigue, dizziness, nausea, abdominal pain, and palpitations.

Rare effects noted in official labeling include gingival hyperplasia (gum enlargement), syncope (fainting), and certain dermatological and musculoskeletal reactions. Very Rare reports include severe hypersensitivity reactions, such as angio-oedema, and elevated liver enzymes.

Safety Considerations and Restrictions

Official prescribing information documents serious adverse reactions, including the possibility of significant hypotension which may, in rare cases, precipitate reflex tachycardia and potentially worsen angina pectoris. The use of Felodipine is subject to several restrictions; it is contraindicated in patients with known hypersensitivity to the drug, as well as those with severe, pre-existing cardiovascular conditions such as unstable angina pectoris or decompensated heart failure.

Safety notes for specific groups exist: individuals with severe hepatic impairment may experience elevated plasma concentrations of the medicine, and use is not recommended during pregnancy or breast-feeding.

Overdose and Emergency Response

Overdose and When to Seek Help

Official regulatory information describes overdose with Plendil (felodipine) as resulting from an extreme exaggeration of its intended effects, primarily impacting the cardiovascular system. The core manifestations are centered on severe hemodynamic instability.

Documented Manifestations and Emergency Action

Overdose presentations documented in official sources include excessive peripheral vasodilatation and resulting marked hypotension (severely low blood pressure). A secondary manifestation may be bradycardia (abnormally slow heart rate). Life-threatening outcomes noted in regulatory documentation include the potential for shock and the risk of myocardial ischaemia in susceptible individuals due to profound hypotension.

Action Mandate	Clinical Condition Trigger
Seek immediate medical help right away	Occurrence of marked hypotension or bradycardia
Contact emergency services	Collapse, seizure, or inability to be awakened

Supportive Treatment and Monitoring

Management is symptomatic and supportive, as no specific antidote is documented in the official prescribing information. Recommended procedures, if justified and performed soon after ingestion, include activated charcoal or gastric lavage. If severe hypotension is present, the patient should be placed supine with the legs elevated and treated with volume expansion and vasopressors as necessary. Hospital monitoring, including an ECG, is required due to the risks associated with the drug's extended-release formulation.

Therapeutic Uses of Plendil

What Plendil Treats: Main Uses and Benefits

Plendil (Felodipine) is generally used to support the management of chronic cardiovascular conditions, focusing on the persistent challenge of high blood pressure and may assist in easing anginal symptoms. Plendil is applied across domains where additional symptomatic support is needed, being considered relevant for essential hypertension and chronic stable angina pectoris.

Managing Chronic Conditions

Plendil is applied in clinical settings that involve elevated arterial pressure, specifically the chronic condition known as essential hypertension. Its primary therapeutic benefit is applied in addressing the persistent challenge of high blood pressure. This helps maintain a sense of stability when symptoms are more noticeable, and may be part of symptomatic management in situations where patients experience conditions associated with increased physiological stress. This benefit is particularly relevant in conditions where symptoms may intensify temporarily later in life, such as Isolated Systolic Hypertension in older adults.

The medication is also relevant in conditions characterized by periods of heightened symptoms related to physical discomfort. Plendil provides support that helps ease the overall symptom burden and contributes to improved comfort during periods of heightened symptoms. It is commonly used to help with symptoms related to heightened physiological activity, providing supportive relief when symptoms interfere with routine activities.

Quick Fact: Relief for Anginal Discomfort Plendil is considered relevant for easing the overall symptom burden associated with recurrent exertional chest discomfort, supports general well-being during symptomatic phases.

Eligibility and Restrictions for Use

Who Can and Cannot Use Plendil?

Plendil (Felodipine) eligibility is strictly defined by regulatory health authorities, focusing on patient age, specific cardiac conditions, and hypersensitivity. The following groups are subject to formal restrictions or prohibitions as defined in official labeling.

Absolute Contraindications

Plendil is contraindicated for patients with a known hypersensitivity to felodipine or other dihydropyridines. It must not be used by women who are pregnant. Absolute prohibitions also apply to patients with recent myocardial infarction, unstable angina pectoris, decompensated heart failure, and specific defects like obstructive hypertrophic cardiomyopathy or severe aortic stenosis.

Restricted and Special Populations

Use is restricted to adults (18 years and older). Safety and efficacy are not established in pediatric patients, and use is not recommended in this group. The medicine is also not recommended for patients with severe hepatic impairment due to the risk of accumulation, or for mothers who are breastfeeding. Caution is required when prescribing for patients with severe renal impairment.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Plendil (felodipine) is metabolized primarily by the Cytochrome P450 3A4 (CYP3A4) enzyme, which forms the basis for its most significant drug interactions, as documented in official regulatory labeling.

Pharmacokinetic Interactions

Co-administration with medicines that strongly inhibit or induce the CYP3A4 enzyme is officially restricted due to the resulting changes in felodipine plasma concentrations.

CYP3A4 Inhibitors: Concurrent use with strong inhibitors (e.g., azole antifungals like ketoconazole or itraconazole, macrolide antibiotics like erythromycin, and HIV protease inhibitors) must be avoided. These agents increase felodipine exposure, which may intensify effects.
CYP3A4 Inducers: Concurrent use with strong inducers (e.g., anticonvulsants like phenytoin, carbamazepine, or phenobarbital, or the herbal supplement St. John's wort) must also be avoided. These agents significantly decrease felodipine exposure.

Food and Beverage Interactions

The absorption and plasma concentration of felodipine are significantly affected by dietary intake. Consumption of grapefruit juice must be avoided as it acts as a CYP3A4 inhibitor, increasing felodipine exposure. Additionally, Plendil should not be taken with a meal rich in fat or carbohydrates, though it may be taken with a light meal.

Mechanism of Action

Selective Blockade of Arterial Calcium Channels

Felodipine’s mechanism is defined by the highly selective blockade of L-type voltage-gated calcium channels ( CaV1), which are located predominantly in the walls of the small arteries (arterioles). The molecule functions as an allosteric modulator, stabilizing the channel in a closed, inactive conformation. This molecular interaction interrupts the influx of Ca^2+ ions, which are the essential cellular triggers for muscle contraction, thus initiating the cascade toward smooth muscle relaxation.

Cellular Cascade and Reduced Vascular Tone

By limiting the intracellular Ca^2+ concentration, the drug reduces the signaling within the cellular contraction cascade in the smooth muscle cells. This action causes widespread arteriolar vasodilation, reducing the resistance the blood encounters in the peripheral circulation and resulting in the physiological consequence of a decrease in Peripheral Vascular Resistance (PVR).

Systemic Effects and Mechanistic Selectivity

Felodipine’s mechanism is notable for its high vascular selectivity. Due to the difference in channel expression and binding kinetics, the blocking action exhibits high selectivity for arterial tissue over cardiac muscle. This sustained reduction in PVR is the final physiological consequence. The ultimate result of this mechanism is a reduction in systemic arterial pressure.

Dosage and Administration Information

Administration Scope

Feature	Instruction
Route of administration	Oral administration only, using the extended-release tablet form.
Dosing schedule	Initial Dose (Adults): 5 mg once daily. Maintenance Dose: 5 mg to 10 mg once daily. Maximum Dose: 10 mg once daily.
Timing in relation to meals (if applicable)	The tablet may be taken without food or following a light meal not rich in fat or carbohydrates. Intake concurrent with grapefruit juice is prohibited.
Age-group administration rules	Older Adults: Initial treatment should begin with the lowest available dose, 2.5 mg once daily.
Missed-dose rules	If a dose is missed, it should be skipped if it is almost time for the next scheduled dose. Do not take a double dose to compensate for the missed one.
Special procedural conditions	Patients with impaired liver function should begin with a lower initial dose of 2.5 mg once daily. Dose adjustment intervals should generally be not less than two weeks.

Instruction Classifications (High-Level)

Classification	Pattern
Administration method type	Oral
Frequency pattern	Once daily (typically in the morning)
Use-context constraints	Physical Integrity (Must be swallowed whole); Beverage Restriction (Avoid grapefruit juice).

Resulting Procedural Structure

Step sequence:

The extended-release tablet must be swallowed whole with water; it must not be divided, crushed, or chewed.
The dosage is taken once daily, preferably in the morning.
Grapefruit juice and products containing it must be avoided while taking this medication.
Adjustments to the dose should occur slowly, with at least a two-week period between changes, and the maximum daily dose is 10 mg.

The administration protocol for Plendil establishes a routine of once-daily oral intake using a formulation designed for stable, long-term therapeutic use. The requirement to swallow the tablet whole preserves the controlled-release system, which is essential for the intended 24-hour delivery profile. The specific dosing guidance for older adults and individuals with hepatic impairment reflects the principle of initiating treatment with the lowest effective dose in vulnerable populations.

Recent Clinical Evidence

Research Evidence Summary

This research section provides a summary of the clinical evidence that evaluated felodipine (Plendil) in the treatment of hypertension (high blood pressure) and chronic stable angina.

Drug Action Investigated

The drug's method of action, which involves blocking voltage-gated L-type calcium channels primarily in vascular smooth muscle cells, has been investigated. This mechanism leads to the relaxation of the blood vessel walls and a resulting decrease in peripheral vascular resistance.

Evidence from Clinical Trials

Studies explored whether the drug is associated with sustained reductions in blood pressure and frequency of angina symptoms.

Hypertension Outcomes

Controlled clinical trials, including randomized, double-blind studies, reported dose-dependent reductions in both systolic and diastolic blood pressure. The antihypertensive effect of the extended-release formulation was observed to be maintained over a 24-hour period. Long-term studies have also investigated the effect of felodipine on surrogate endpoints, such as the regression of left ventricular hypertrophy (LVH) in patients with isolated systolic hypertension.

Tolerability Profile

In clinical trials, the most frequently reported adverse events associated with felodipine included peripheral edema (swelling of the ankles/feet), headache, and flushing. These events are often dose-dependent and relate to the drug's vasodilatory effect. Studies reported that the drug was generally acceptable in most adults, but individuals are encouraged to discuss all potential side effects with a healthcare provider.

Frequently Asked Questions (FAQ)

Common questions about Plendil (FAQ)

Q: How quickly should I expect Plendil to start lowering my blood pressure?

A: Regulatory data indicates that a reduction in blood pressure generally begins within 2 to 5 hours after taking the extended-release tablet. Achieving the full, sustained therapeutic effect may require consistent use over a longer period, as determined by a healthcare provider.

Q: Does Plendil cause weight gain or fluid retention?

A: Peripheral edema, which is swelling typically affecting the ankles or feet, is the most commonly reported side effect. Official documents classify this effect as often mild and considered localized, not associated with generalized fluid retention in most cases. Weight gain itself is not listed as a common side effect of the medication.

Q: Can taking Plendil affect my sleep or cause insomnia?

A: Sleep problems, specifically insomnia, have been reported as a possible adverse reaction in post-marketing or less common side effect summaries. If you experience persistent changes in your sleep patterns after starting this medication, it is advisable to discuss this with a healthcare provider.

Q: Can older adults or seniors safely take Plendil?

A: Regulatory information suggests that older adults may be more sensitive to the drug’s effects. For this reason, official guidance recommends starting with the lowest available dose. Any necessary dose adjustments should be made gradually, based on the response and monitoring advised by a healthcare provider.

Q: Does Plendil interact with common over-the-counter pain relievers like ibuprofen?

A: Official guidance notes that the combination of Plendil with Nonsteroidal Anti-Inflammatory Drugs (NSAIDs), such as ibuprofen, may potentially cause blood pressure to increase. If these medications are used concurrently, close monitoring of blood pressure is typically advised by healthcare professionals.

Q: Is it normal to feel dizzy or lightheaded after starting Plendil?

A: Dizziness and lightheadedness are documented as common side effects when initiating therapy with Plendil. These effects are expected as a result of the drug’s action to lower blood pressure. Individuals starting the medication should be aware of these possible sensations, particularly during the initial adjustment period.

Q: Can taking Plendil cause constipation or other stomach issues?

A: Yes, regulatory documents indicate that gastrointestinal issues such as constipation, nausea, and abdominal pain are listed among the possible side effects, ranging from common to less common.

Q: Does Plendil interact with vitamin or mineral supplements?

A: Plendil is primarily metabolized by the CYP3A4 enzyme, and it interacts with substances that strongly affect this enzyme. While most vitamins and minerals are generally not listed as interacting, regulatory labels indicate that the herbal supplement St. John's wort is a known CYP3A4 inducer and its use should be avoided.

Q: Why is Plendil used to treat Raynaud's phenomenon in some cases?

A: Plendil’s primary approved uses are for high blood pressure and angina. Its core mechanism involves promoting arterial vasodilation (widening of blood vessels), an effect that is sometimes utilized for managing related circulatory conditions like Raynaud's phenomenon, although this is an off-label use not approved by all regulators.

Q: How is the effectiveness of Plendil usually monitored by a doctor?

A: Clinical trials indicate that the sustained reduction in systolic and diastolic blood pressure over time is a key measure used to monitor the effectiveness of Plendil for hypertension. Close monitoring of blood pressure is important when the dosage is being adjusted.

Q: Is Plendil safe for use during pregnancy or while breastfeeding?

A: Plendil is generally not recommended during pregnancy and is contraindicated by some regulatory authorities due to potential risks. Furthermore, the drug is known to be excreted into human milk. A healthcare provider must determine the appropriate course of action, which may involve discontinuing the medication or discontinuing nursing.

Q: What is the maximum effective duration of a single Plendil tablet?

A: The extended-release formulation of Plendil is specifically designed to provide effective blood pressure control over a 24-hour period. This sustained action is supported by the drug's elimination half-life, which is approximately 25 hours.

Q: Can Plendil cause gastrointestinal upset or heartburn?

A: Yes, official product information includes reports of gastrointestinal upset, along with specific issues like acid or sour stomach and heartburn, as less common side effects associated with the medication.

Q: Does Plendil affect sexual function in men or women?

A: Official post-marketing and adverse event reports list certain rare effects related to sexual function. These include reports of decreased interest in sexual intercourse and, in men, inability to have or keep an erection.

Q: Are there any mood-related side effects associated with Plendil?

A: Yes, rare reports of mood-related changes are noted in regulatory safety summaries. These include feelings of fear or nervousness, and experiences of discouragement or feeling sad/empty.

Q: What are the warning signs that I should stop taking Plendil and contact a doctor?

A: Official labeling states that immediate medical attention should be sought if severe symptoms are experienced. These include signs such as swelling in the face, eyes, lips, tongue, or legs, chest pain, fainting (syncope), problems breathing, or signs of an allergic reaction.

Q: Is it okay to drive or operate machinery while taking Plendil?

A: Because Plendil can potentially cause dizziness, individuals should avoid driving or operating hazardous machinery until they are aware of how the medication affects them.

Q: What should I tell my dentist or surgeon about taking Plendil?

A: Official patient information recommends informing all healthcare providers, including dentists and surgeons, that you are taking this medication. Additionally, due to the rare risk of gum swelling (gingival hyperplasia), maintaining good dental hygiene is generally recommended.

Q: How long does it takes for Plendil to be completely cleared from the body?

A: The elimination half-life of Plendil is approximately 25 hours. This refers to the time it takes for the concentration of the drug in the body to drop by half. The majority of the drug and its breakdown products are removed from the body via the kidneys.

How should Plendil be stored and disposed of?

How to Store and Dispose of Plendil?

Plendil (felodipine) extended-release tablets must be stored according to specific regulatory requirements to maintain their stability.

Storage Conditions

Temperature: Store at Controlled Room Temperature, defined as 20 to 25 C (68 to 77 F), protecting the product from freezing.

Protection: The medication must be kept in its original container, tightly closed, and shielded from light and moisture.

Child Safety: It is mandatory to store the product out of the sight and reach of children.

Disposal Instructions

Unused or expired Plendil must be disposed of following regulated protocols. Regulatory instructions state do not throw away the medicine in household waste or dispose of it in wastewater (e.g., down the sink or toilet). Instead, return the unused product to a pharmacy or local waste disposal service.

Plendil