Naproxen

Introduction

Generic Name: Naproxen
Brand Names: Aleve®, Naprosyn®, Anaprox®, Naprelan®
Chemical Formula: C₁₄H₁₄O₃

Naproxen is a widely used nonsteroidal anti-inflammatory drug (NSAID) that has multiple therapeutic purposes, which includes pain relief, inflammation reduction, and antipyretic action. It is a part of the class of NSAIDs which are known as propionic acid derivatives, similar to ibuprofen, and is mostly prescribed for a variety of conditions such as arthritis, acute gout, tendinitis and menstrual pain.

Unlike some other NSAIDs, naproxen has a comparatively longer half-life, which means it can act for extended periods with fewer doses. This pharmacokinetic property makes it a popular choice for conditions where consistent pain or inflammation need to be addressed. Naproxen works by inhibiting the enzyme cyclooxygenase (COX), which reduces the production of prostaglandins, substances in the body which are responsible for pain, inflammation, and fever.

Uses

Naproxen is usually given for the relief of mild to moderate pain and is often used to treat some of the following conditions :

Osteoarthritis and Rheumatoid Arthritis:
Naproxen is commonly prescribed for chronic conditions like osteoarthritis and rheumatoid arthritis. It helps to decrease the inflammation in the joints along with minimizing pain and overall improving joint function.
Ankylosing Spondylitis:
This form of arthritis primarily affects the spine. This drug can help reduce the spinal inflammation and relieve pain, which helps improve the flexibility and mobility in patients suffering from these conditions.
Acute Gout Attacks:
During gout flares, naproxen is often prescribed to reduce joint swelling, pain, and inflammation. It is particularly effective in decreasing the intense pain associated with acute gout attacks.
Menstrual Pain/Cramps:
Naproxen is one of the most effective NSAIDs for managing menstrual cramps.
Headaches and Migraines:
Naproxen is also used for tension headaches and migraine relief, particularly when combined with other potent medications such as sumatriptan. It can help reduce the intensity of headaches and associated symptoms.
Muscle Pain and Injuries:
It is also effective for treating soft tissue injuries which include sprains and strains.
Postoperative Pain:
This drug is sometimes used after minor surgeries to limit the pain and swelling, creating an alternative for patients with a non-opioid pain management option.

Dosage

The dosage of naproxen varies depending on the individual factors like condition being treated, the patient’s age and overall health and medical history. This drug is available in both immediate-release and extended-release formulations.

Adults:

For acute pain, the typical dose is 250 mg to 500 mg is taken twice a day.
For chronic conditions like arthritis, the dose may range from 500 mg to 1,000 mg per day in divided doses.

Children (12 years and older):

Naproxen is generally prescribed in lower doses for children, with the typical dose being 5 mg to 10 mg/kg/day. The maximum dose should not exceed 660 mg/day unless specifically advised by a physician.

Elderly:

Elderly patients may be given lower doses due to the increased risk of gastrointestinal and renal side effects.

For extended-release formulations, such as Naprelan®, the dose of this drug is generally 500 mg to 1,000 mg once daily. One must carefully follow the physician’s or pharmacist’s guidance on dosing, especially for long-term use.

Mechanism of Action

Naproxen works by blocking both COX-1 and COX-2 enzymes, which are crucial in the generation of prostaglandin. Prostaglandins are the lipidic molecules which play a key role in promoting inflammation, pain, and fever as part of the body’s immune response. By inhibiting these enzymes, naproxen decreases the production of prostaglandins, leading to reduction in inflammation, pain, and fever.

However, inhibiting COX-1 can lead to gastrointestinal side effects, such as ulcers and bleeding, as this enzyme also plays a role in protecting the lining of the stomach.

Pharmacokinetics

Naproxen is much rapidly absorbed from the gastrointestinal tract, and its peak plasma concentration is attained within 1-2 hours after ingestion of immediate-release formulations. It has a plasma half-life of approximately 12-17 hours, which is relatively long when compared to other NSAID. This allows for twice-daily dosing in most cases.

Naproxen is highly protein-bound, and only a small percentage remains in free form in the blood. It is highly metabolized in the liver and excreted mainly through the urine.

Side Effects

Although naproxen is safe at normal doses, it may cause side effects, particularly with prolonged use or at higher doses. Some of the side effects include:

Common Side Effects:

Nausea
Heartburn
Indigestion
Dizziness
Headache

Serious Side Effects:

Gastrointestinal Issues: Due to its COX-1 inhibition activity, naproxen can cause stomach ulcers, bleeding, or perforation, particularly in people with a history of ulcers or gastrointestinal bleeding.
Cardiovascular Risks: Long-term use of naproxen, especially at high doses, can lead to an increased risk of heart attacks and strokes.
Renal Impairment: Naproxen can affectthe kidney function, particularly in people with pre-existing kidney issues or symptoms. Prolonged use may eventually lead to renal failure in rare and severe cases.
Hepatotoxicity: In some cases, naproxen can cause damage to the liver, especially in susceptible people or those with existing liver diseases.

In case of any of these serious side effects, it is essential to stop the medication and seek medical attention immediately.

Contraindications

Naproxen should not be used by individuals who:

Have a history of gastrointestinal bleeding or ulcers.
Suffer from severe kidney or liver impairment or diseases.
Are allergic to naproxen or sensitive to other NSAIDs.
Have a previous history of cardiovascular diseases, such as heart attacks or strokes.
Women in the third trimester of pregnancy.

Drug Interactions

Naproxen can interact with a variety of medications, potentially leading to adverse effects or reduced efficacy. Some key interactions include:

Anticoagulants (e.g., Warfarin): Increased risk of bleeding with subsequent dosing.
Corticosteroids: Increased risk of gastrointestinal ulcers or bleeding with concomitant administration of this drug.
Antihypertensives (e.g., Angiotensin Converting Enzyme – ACE inhibitors, Angiotensin Receptor blockers – ARBs): Reduced efficacy of antihypertensive medications.
Other NSAIDs: Significantly increased risk of adverse effects such as gastrointestinal bleeding and kidney damage.

Before taking naproxen, it is crucial to inform your healthcare provider about all medications and supplements you are using to avoid potential drug interactions.

Other Considerations

Pregnancy and Lactation

Naproxen should be strictly avoided in the third trimester of pregnancy due to the risk of injury to the fetus, such as premature closure of the ductus arteriosus. It may be used with caution during the first and second trimesters but only under strict medical supervision.
Naproxen is excreted in very less amounts in the breast milk, and while it’s considered safe for short-term use during breastfeeding, prolonged use is absolutely not recommended.

Elderly Patients

Elderly patients are at more risk to suffer the gastrointestinal and renal side effects of NSAIDs, including naproxen. Effective lower doses are often prescribed along with regular monitoring of kidney and liver function is vital during long-term therapy.

Warnings and Precautions

Gastrointestinal Risks:

Naproxen increases the risk of serious gastrointestinal issues, including bleeding, ulceration, and perforation of the stomach or intestines. These risks are heightened in older adults and those with a history of peptic ulcer disease or gastrointestinal bleeding.

Cardiovascular Risks:

Patients with existing cardiovascular disease or risk factors for heart disease should use naproxen with caution and under strict medical supervision.

Kidney and Liver Function:

Naproxen can alter the kidney function, particularly in individuals with existing renal conditions. It can also elevate liver enzymes, and in rare cases, cause serious liver damage hence the regular monitoring of kidney and liver function is recommended for long-term therapy.

Allergic Reactions:

Rarely naproxen can cause serious allergic reactions in some people, including anaphylaxis, a potentially life-threatening condition. Symptoms of an allergic reaction may include rash, itching, swelling, blisters and difficulty breathing. Seek immediate medical attention if you experience any of these symptoms

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