Tenoxicam

Usage

Tenoxicam is prescribed for the symptomatic relief of pain and inflammation associated with osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, and other musculoskeletal disorders like tendinitis, bursitis, and periarthritis. It can also be used for post-operative pain, acute gout, and primary dysmenorrhea. Its pharmacological classification is a non-steroidal anti-inflammatory drug (NSAID). Tenoxicam works by inhibiting cyclooxygenase (COX) enzymes, primarily COX-2. This reduces the production of prostaglandins, which are key mediators of inflammation and pain.

Alternate Names

While Tenoxicam is the generic name, it’s marketed under various brand names like Tilcotil, Tilatil, Tilcitin, Alganex, Mobiflex, and Reutenox.

How It Works

Pharmacodynamics: Tenoxicam exerts its anti-inflammatory and analgesic effects primarily through the inhibition of COX-2, thus reducing prostaglandin synthesis. It exhibits a long duration of action due to its long half-life.

Pharmacokinetics:

• Absorption: Tenoxicam is well-absorbed orally, with near 100% bioavailability. Taking it with food can delay absorption but does not affect the overall extent of absorption.
• Metabolism: Primarily metabolized in the liver, mainly via hydroxylation to inactive metabolites.
• Elimination: Tenoxicam has a long elimination half-life of approximately 72 hours, primarily eliminated through renal excretion of metabolites.

Mode of Action: Tenoxicam binds to and inhibits COX enzymes, preventing arachidonic acid from being converted into prostaglandins. This inhibition reduces inflammation and pain.

Receptor Binding/Enzyme Inhibition: Primarily inhibits COX-2 enzyme.

Elimination Pathways: Excreted renally as metabolites, with a small amount excreted through the biliary route.

Dosage

Standard Dosage

Adults: A single daily dose of 20 mg taken orally, preferably with or after food. For some conditions, like postoperative pain or acute gout, the dose can be temporarily increased to 40 mg daily as directed by a physician. The smallest effective dose should be used.

Children: Not recommended for children and adolescents under 18 years due to a lack of adequate safety and efficacy data.

Special Cases:

• Elderly Patients: Start at a lower dose (e.g., 10 mg) and increase cautiously as needed, due to the increased risk of side effects. Monitor closely for adverse events.
• Patients with Renal Impairment: Reduce dosage as needed based on renal function. Careful monitoring of renal function is recommended.
• Patients with Hepatic Dysfunction: Dosage adjustment is necessary, minimizing the dose in patients with hepatic impairment. Contraindicated in severe hepatic dysfunction.
• Patients with Comorbid Conditions: Use cautiously in patients with cardiovascular disease, hypertension, diabetes, or a history of gastrointestinal ulcers or bleeding. Consider gastroprotective agents (e.g., misoprostol or proton pump inhibitors) for patients with increased GI risk.

Clinical Use Cases

The standard 20 mg daily dosage typically applies to most clinical settings. In cases of post-operative pain, a higher dose of 40 mg daily for up to 5 days may be employed. No specific dosage adjustments are typically recommended for intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations, but clinical judgment is paramount. Start with the lowest effective dose and titrate upwards as needed based on patient response and tolerance.

Dosage Adjustments

Dosage adjustments are crucial for elderly patients and those with renal or hepatic impairment. Closely monitor patients with these conditions for adverse events and adjust dosage accordingly.

Side Effects

Common Side Effects:

Dyspepsia, nausea, abdominal pain, constipation, diarrhea, flatulence, dizziness, headache, edema, and skin rash.

Rare but Serious Side Effects:

Gastrointestinal bleeding, peptic ulcers, perforation, anaphylaxis, Stevens-Johnson syndrome, toxic epidermal necrolysis, renal impairment, hepatic dysfunction, cardiovascular events (e.g., myocardial infarction, stroke), blood disorders (e.g., thrombocytopenia, leukopenia), and angioedema.

Long-Term Effects:

Chronic use can potentially lead to renal or hepatic damage, cardiovascular complications, and gastrointestinal issues.

Adverse Drug Reactions (ADR):

Any signs of gastrointestinal bleeding or ulceration, skin reactions, hepatic or renal dysfunction, or cardiovascular events should be considered serious ADRs requiring immediate medical attention.

Contraindications

• Hypersensitivity to tenoxicam or any NSAIDs.
• History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs.
• Active peptic ulcer or gastrointestinal bleeding.
• Severe heart failure.
• Severe hepatic impairment.
• Third trimester of pregnancy.
• Perioperative pain in patients undergoing coronary artery bypass graft (CABG) surgery.

Drug Interactions

Tenoxicam can interact with numerous medications, including:

• Anticoagulants (e.g., warfarin): Increased risk of bleeding.
• Antihypertensives: May decrease their effectiveness.
• Lithium: Increased lithium levels.
• Methotrexate: Enhanced methotrexate toxicity.
• Diuretics: May reduce diuretic efficacy.
• Other NSAIDs and salicylates: Increased risk of gastrointestinal side effects.
• Corticosteroids: Increased risk of gastrointestinal ulceration.
• SSRIs: Increased risk of GI bleeding.

Pregnancy and Breastfeeding

• Pregnancy: Tenoxicam is contraindicated during the third trimester due to the risk of premature closure of the ductus arteriosus and potential complications during labor. Use with caution during the first and second trimesters, as NSAIDs can cause fetal renal dysfunction.
• Breastfeeding: Tenoxicam passes into breast milk. It’s generally recommended to avoid its use during breastfeeding.

Drug Profile Summary

• Mechanism of Action: COX-2 inhibitor, reducing prostaglandin synthesis.
• Side Effects: GI upset, dizziness, headache; rarely, GI bleeding, ulcers, Stevens-Johnson syndrome.
• Contraindications: Hypersensitivity to NSAIDs, active peptic ulcer, severe hepatic/heart failure, third-trimester pregnancy.
• Drug Interactions: Anticoagulants, antihypertensives, lithium, methotrexate, other NSAIDs.
• Pregnancy & Breastfeeding: Avoid in third trimester and during breastfeeding. Use cautiously in the first and second trimesters.
• Dosage: Adults: 20 mg once daily; up to 40 mg for certain conditions. Not for children under 18.
• Monitoring Parameters: Renal function, liver function tests, blood pressure, signs of GI bleeding.

Popular Combinations

While not a “combination drug,” tenoxicam may be prescribed along with gastroprotective agents (e.g., misoprostol, proton pump inhibitors) to minimize gastrointestinal risks, particularly in patients with risk factors.

Precautions

• General Precautions: Assess for allergies, renal/hepatic function, and cardiovascular risk factors.
• Specific Populations: See “Dosage - Special Cases.”
• Lifestyle Considerations: Avoid or limit alcohol consumption. Caution while driving or operating machinery due to potential dizziness or drowsiness.

FAQs (Frequently Asked Questions)

Q1: What is the recommended dosage for Tenoxicam?

A: The standard adult dosage is 20 mg once daily, orally. This can be increased to 40 mg daily for short-term use in certain conditions like postoperative pain or acute gout. Elderly patients and those with renal/hepatic impairment often require lower doses. Not recommended for children under 18.

Q2: How should Tenoxicam be administered?

A: Tenoxicam tablets should be swallowed whole with plenty of water, preferably with or after food to minimize gastrointestinal upset. Do not crush or chew the tablets.

Q3: What are the most common side effects of Tenoxicam?

A: Common side effects include dyspepsia, nausea, abdominal pain, constipation, diarrhea, headache, dizziness, and skin rash.

Q4: When is Tenoxicam contraindicated?

A: Tenoxicam is contraindicated in patients with hypersensitivity to NSAIDs, active peptic ulcer or GI bleeding, severe hepatic or renal impairment, severe heart failure, and during the third trimester of pregnancy.

Q5: What are the serious side effects of Tenoxicam that warrant immediate medical attention?

A: Serious side effects include gastrointestinal bleeding or ulcers, severe skin reactions (e.g., Stevens-Johnson syndrome), signs of renal or hepatic impairment, cardiovascular events (MI, stroke), and allergic reactions.

Q6: Can Tenoxicam be used during pregnancy or breastfeeding?

A: Tenoxicam is contraindicated during the third trimester of pregnancy. It should be used with caution during the first and second trimesters. Its use during breastfeeding is generally avoided due to the potential for neonatal exposure.

Q7: Does Tenoxicam interact with other medications?

A: Yes, Tenoxicam can interact with other medications, including anticoagulants, antihypertensives, lithium, methotrexate, and other NSAIDs. A full review of concomitant medications is essential before prescribing.

Q8: What are the long-term safety concerns with Tenoxicam use?

A: Chronic use of Tenoxicam can potentially increase the risk of renal or hepatic damage, cardiovascular complications, and gastrointestinal problems. Regular monitoring and the lowest effective dose are recommended for long-term use.

Q9: How does Tenoxicam compare to other NSAIDs?

A: Tenoxicam has a longer half-life than many other NSAIDs, allowing for once-daily dosing. Its selectivity for COX-2 might offer some advantages in terms of GI tolerability compared to non-selective NSAIDs, but it still carries significant GI risks.

Q10: How long does it take for Tenoxicam to reach its peak effect?

A: While peak plasma concentrations are reached within a few hours, the full therapeutic effect of Tenoxicam, especially in chronic conditions, may take several days or weeks to become apparent.