ORTHO FLEX PLUS TABLETS

Indications

• Symptomatic relief of mild to moderate osteoarthritis of the knee

Dosage

Children: Refer to the BNF for Children for

Adults: 200–400 mg daily, maximum 6.5 mg/kg per day, or 1250 mg once daily, or 1500 mg once daily dissolved in at least 250 mL of water; review treatment if no benefit after 2–3 months.

Mechanism of action

The mechanism of action of glucosamine in joint health is not entirely clear, but it is believed to involve several pathways. Glucosamine is a precursor for glycosaminoglycans, which are essential for cartilage integrity. It may also reduce inflammation by inhibiting interferon gamma and Nuclear factor kappa B subunit 65 (NF-κB p65), which could improve symptoms of arthritis and joint pain. Upon uptake by living cells, glucosamine reacts with ATP to form glucosamine-6-phosphate, further contributing to glycosaminoglycan synthesis.

Pharmacodynamics

Glucosamine is theorized to provide essential building blocks for the synthesis of glycosaminoglycans, potentially slowing the progression of osteoarthritis and alleviating joint pain. Although some studies have indicated modest improvements in joint pain and function among users, the overall evidence remains inconclusive. Glycosaminoglycans are critical for maintaining cartilage elasticity, strength, and flexibility, which are vital for joint health.

Pharmacokinetics

After oral administration, glucosamine is absorbed in the gastrointestinal tract and transported into the bloodstream, where it is metabolized into various forms, including glucosamine-6-phosphate. The exact pharmacokinetics, such as absorption rate and half-life, remain largely undefined, and much of the data is derived from animal studies. Further research is required to clarify its pharmacokinetic profiles in humans.

Adverse effects

• Constipation
• Diarrhoea
• Fatigue
• Gastrointestinal discomfort
• Headache
• Nausea
• Flushing
• Skin reactions

Interactions

• Glucosamine + warfarin: Severe (increases anticoagulant effect)
• Glucosamine + coumarins: Severe (increases anticoagulant effect)
• Glucosamine + acenocoumarol: Unknown (decreases anticoagulant effect)
• Glucosamine + coumarins: Unknown (decreases anticoagulant effect)

Precautions

• Asthma
• Impaired glucose tolerance
• Predisposition to cardiovascular disease

Pregnancy

Safety during pregnancy has not been established; consult with a healthcare provider.

Breast-feeding

Safety during breastfeeding has not been established; consult with a healthcare provider.

Storage

Store in a cool, dry place away from direct sunlight.

Formulations

• Alateris®
• Dolenio®
• Glusartel®

Indications

• Vitamin D deficiency
• Rickets
• Osteomalacia
• Osteoporosis
• Hypoparathyroidism

Dosage

Adults: The usual adult dose for vitamin D deficiency is 800 to 2000 IU daily, depending on the severity of deficiency and clinical condition. Higher doses may be used under medical supervision.

Mechanism of action

Cholecalciferol is converted to its active forms, 25-hydroxyvitamin D in the liver and 1,25-dihydroxyvitamin D in the kidneys. These metabolites enhance the intestinal absorption of calcium and phosphorus, increase serum calcium levels, and mobilize these minerals from bone. This process is regulated by parathyroid hormone, which influences calcium and phosphate metabolism, particularly in the kidneys.

Pharmacodynamics

The pharmacodynamics of cholecalciferol involve its conversion to active metabolites that play a significant role in calcium and phosphorus homeostasis. The metabolites facilitate intestinal absorption of these minerals, promote bone mineralization, and influence renal reabsorption. The onset of action occurs within 10 to 24 hours following administration, as metabolic activation is required for its biological effects.

Pharmacokinetics

Cholecalciferol is absorbed in the gastrointestinal tract, and its absorption is enhanced by the presence of dietary fats. It is transported in the bloodstream bound to vitamin D-binding protein. Once in the liver, it undergoes hydroxylation to form 25-hydroxyvitamin D, which is further converted in the kidneys to the active form, 1,25-dihydroxyvitamin D. The elimination half-life of cholecalciferol varies, typically spanning several days, and it is primarily excreted in bile and urine.

Adverse effects

• Hypercalcemia
• Hypercalciuria
• Nausea
• Vomiting
• Constipation
• Weakness
• Fatigue

Interactions

• May enhance the effects of thiazide diuretics, leading to increased risk of hypercalcemia
• Anticonvulsants may increase metabolism of vitamin D, leading to reduced effectiveness
• Cholestyramine may reduce absorption of vitamin D

Precautions

• Monitor serum calcium levels in patients with renal impairment
• Caution in patients with a history of hypercalcemia or hyperparathyroidism
• Use with caution in patients taking other medications that affect calcium metabolism

Pregnancy

Cholecalciferol can be used during pregnancy if indicated, as vitamin D is essential for fetal bone development.

Breast-feeding

Cholecalciferol is excreted in breast milk, but is generally considered safe during breastfeeding.

Storage

Store in a cool, dry place, away from light. Keep out of reach of children.

Formulations

• Capsules
• Tablets
• Liquid formulations

Indications

• Osteoarthritis
• Joint pain
• Cartilage repair
• Joint health maintenance

Dosage

Children: Refer to healthcare professionals for guidance on dosing in children, as specific pediatric dosing information is not well established.

Adults: Refer to specific product labeling and consult healthcare professionals for guidance on dosing, as dosages can vary based on formulations and clinical guidelines.

Mechanism of action

Chondroitin works primarily by providing the building blocks necessary for the synthesis of glycosaminoglycans, which are critical components of cartilage. It is thought to inhibit the enzymes that break down cartilage, thereby promoting cartilage repair while also exhibiting anti-inflammatory properties. Additionally, chondroitin may enhance the retention of water in the cartilage, improving its elasticity and resilience.

Pharmacodynamics

Chondroitin has been shown to modulate inflammatory responses within the joints and may help to improve joint mobility and reduce pain associated with osteoarthritis. Its effects on cartilage metabolism are believed to contribute to its therapeutic benefits, although the clinical efficacy may vary among individuals. The anti-inflammatory properties may also contribute to a reduction in joint swelling and discomfort.

Pharmacokinetics

Chondroitin is poorly absorbed from the gastrointestinal tract, with bioavailability ranging from 12% to 36%. It is distributed in the extracellular matrix of cartilage and other connective tissues. Metabolism of chondroitin is not well understood, but it is believed to be metabolized in the liver. The elimination half-life in humans is not well defined, and it is primarily excreted via urine as metabolites. The effects of food on its absorption are still under investigation.

Adverse effects

• Nausea
• Diarrhea
• Constipation
• Abdominal pain
• Headache
• Skin reactions

Interactions

• Anticoagulants (e.g., warfarin) - may increase the risk of bleeding
• NSAIDs - may affect the efficacy of these medications

Precautions

• Use with caution in patients with a history of bleeding disorders
• Caution is advised in patients undergoing surgery due to potential bleeding risk
• Patients with shellfish allergies should consult a physician as some chondroitin supplements are derived from marine sources

Pregnancy

There is insufficient reliable information regarding the safety of chondroitin during pregnancy. It is advisable to avoid use unless prescribed by a healthcare professional.

Breast-feeding

It is not known if chondroitin is excreted in human milk. Caution is advised for nursing mothers considering its use.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Capsule
• Tablet
• Powder
• Liquid

Indications

• Osteoarthritis
• Dermal filler for aesthetic procedures
• Dry eye syndrome
• Surgical adjunct in ophthalmic procedures

Dosage

Children: Refer to specific product guidelines for dosing, as it varies by formulation and indication.

Adults: Refer to specific product guidelines for dosing, as it varies by formulation and indication.

Mechanism of action

Hyaluronic acid exerts its effects primarily through its ability to bind and retain water, thus contributing to tissue hydration and lubrication. In joints, it provides viscoelastic properties to synovial fluid, reducing friction and facilitating smooth movement. In dermal applications, it promotes skin moisture and elasticity by attracting water to the skin surface.

Pharmacodynamics

The pharmacodynamic properties of hyaluronic acid are attributed to its capacity to form a gel-like structure upon hydration, which enhances its mechanical and biological functions. In joint injections, it alleviates pain and improves function in patients with osteoarthritis by restoring the viscosity of synovial fluid. In cosmetic applications, its hydrophilic nature increases skin volume and smoothness, reducing the appearance of wrinkles.

Pharmacokinetics

Hyaluronic acid is administered via various routes, including intra-articular injections, topical formulations, and subdermal injections. After administration, it is distributed in the extracellular matrix, where it remains for varying durations depending on the formulation and site of application. The half-life can range from hours to days; however, once in the body, it is metabolized by hyaluronidases and other enzymes, with catabolites excreted primarily through urine.

Adverse effects

• Injection site reactions
• Allergic reactions
• Headache
• Dizziness

Precautions

• Use with caution in patients with a history of hypersensitivity to hyaluronic acid or any of its components
• Consider potential risks in patients with bleeding disorders or those on anticoagulant therapy

Pregnancy

Hyaluronic acid is generally considered safe for topical use during pregnancy, but systemic safety has not been fully established. Consult a healthcare provider before use.

Breast-feeding

Topical hyaluronic acid is considered safe for use during breastfeeding, but consult a healthcare provider for systemic use.

Storage

Store at room temperature, away from direct sunlight. Once opened, use as directed and do not freeze.

Formulations

• Injectable solutions
• Topical gels
• Ophthalmic solutions

Indications

• Osteoarthritis
• Joint pain
• Muscle soreness
• Inflammatory conditions

Dosage

Children: Refer to relevant guidelines or clinical studies for specific dosing recommendations, as it may vary based on the condition being treated.

Adults: Refer to relevant guidelines or clinical studies for specific dosing recommendations, as it may vary based on the condition being treated.

Mechanism of action

Methylsulfonylmethane is thought to exert its therapeutic effects through several mechanisms, including the reduction of inflammation and oxidative stress. It may enhance the availability of sulfur, which is essential for the synthesis of collagen and other connective tissues. MSM may also modulate immune responses and inhibit the production of pro-inflammatory cytokines, thereby contributing to its analgesic effects.

Pharmacodynamics

MSM exhibits anti-inflammatory and antioxidant properties, which may help to reduce pain and improve joint function in conditions such as osteoarthritis. Its effects on collagen synthesis may support joint health and integrity, while its ability to scavenge free radicals may protect tissues from oxidative damage. Clinical studies suggest that MSM can lead to reductions in pain and improvements in physical function.

Pharmacokinetics

After oral administration, MSM is rapidly absorbed and distributed throughout the body. It has a relatively short half-life, necessitating multiple doses throughout the day for sustained effects. MSM is metabolized primarily in the liver, and its metabolites are excreted via the urine. The bioavailability of MSM may vary based on individual factors, including gastrointestinal health and the presence of food.

Adverse effects

• Gastrointestinal disturbances such as diarrhea
• Nausea
• Headaches
• Fatigue
• Skin rashes

Precautions

• Use with caution in patients with gastrointestinal disorders
• Should not be used in patients with known hypersensitivity to methylsulfonylmethane

Pregnancy

The safety of methylsulfonylmethane during pregnancy has not been established. It is advisable to avoid use unless clearly needed and directed by a healthcare professional.

Breast-feeding

There is limited information on the excretion of methylsulfonylmethane in human breast milk. Caution is advised when administering to nursing mothers.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Mechanism of action

Most individuals naturally generate adequate amounts of vitamin D through ordinary dietary intake of vitamin D (in some foods like eggs, fish, and cheese) and natural photochemical conversion of the vitamin D3 precursor 7-dehydrocholesterol in the skin via exposure to sunlight. Conversely, vitamin D deficiency can often occur from a combination of insufficient exposure to sunlight, inadequate dietary intake of vitamin D, genetic defects with endogenous vitamin D receptor, or even severe liver or kidney disease. Such deficiency is known for resulting in conditions like rickets or osteomalacia, all of which reflect inadequate mineralization of bone, enhanced compensatory skeletal demineralization, resultant decreased calcium ion blood concentrations, and increases in the production and secretion of parathyroid hormone. Increases in parathyroid hormone stimulate the mobilization of skeletal calcium and the renal excretion of phosphorus. This enhanced mobilization of skeletal calcium leads towards porotic bone conditions. Ordinarily, while vitamin D3 is made naturally via photochemical processes in the skin, both itself and vitamin D2 can be found in various food and pharmaceutical sources as dietary supplements. The principal biological function of vitamin D is the maintenance of normal levels of serum calcium and phosphorus in the bloodstream by enhancing the efficacy of the small intestine to absorb these minerals from the diet. At the liver, vitamin D3 or D2 is hydroxylated to 25-hydroxyvitamin D and then finally to the primary active metabolite 1,25-dihydroxyvitamin D in the kidney via further hydroxylation. This final metabolite binds to endogenous vitamin d receptors, which results in a variety of regulatory roles - including maintaining calcium balance, the regulation of parathyroid hormone, the promotion of the renal reabsorption of calcium, increased intestinal absorption of calcium and phosphorus, and increased calcium and phosphorus mobilization of calcium and phosphorus from bone to plasma to maintain balanced levels of each in bone and the plasma. In particular, calcitriol interacts with vitamin D receptors in the small intestine to enhance the efficiency of intestinal calcium and phosphorous absorption from about 10-15% to 30-40% and 60% increased to 80%, respectively. Furthermore, calcitriol binds with vitamin D receptors in osteoblasts to stimulate a receptor activator of nuclear factor kB ligand (or RANKL) which subsequently interacts with receptor activator of nuclear factor kB (NFkB) on immature preosteoclasts, causing them to become mature bone-resorbing osteoclasts. Such mature osteoclasts ultimately function in removing calcium and phosphorus from bone to maintain blood calcium and phosphorus levels. Moreover, calcitriol also stimulates calcium reabsorption from the glomerular filtrate in the kidneys. Additionally, it is believed that when calcitriol binds with nuclear vitamin D receptors, that this bound complex itself binds to retinoic acid X receptor (RXR) to generate a heterodimeric complex that consequently binds to specific nucleotide sequences in the DNA called vitamin D response elements. When bound, various transcription factors attach to this complex, resulting in either up or down-regulation of the associated gene's activity. It is thought that there may be as much as 200 to 2000 genes that possess vitamin D response elements or that are influenced indirectly to control a multitude of genes across the genome. It is in this way that cholecalciferol is believed to function in regulating gene transcription associated with cancer risk, autoimmune disorders, and cardiovascular disease linked to vitamin D deficiency. In fact, there has been some research to suggest calcitriol may also be able to prevent malignancies by inducing cellular maturation and inducing apoptosis and inhibiting angiogenesis, exhibit anti-inflammatory effects by inhibiting foam cell formation and promoting angiogenesis in en

Pharmacodynamics

The in vivo synthesis of the predominant two biologically active metabolites of vitamin D occurs in two steps. The first hydroxylation of vitamin D3 cholecalciferol (or D2) occurs in the liver to yield 25-hydroxyvitamin D while the second hydroxylation happens in the kidneys to give 1, 25-dihydroxyvitamin D. These vitamin D metabolites subsequently facilitate the active absorption of calcium and phosphorus in the small intestine, serving to increase serum calcium and phosphate levels sufficiently to allow bone mineralization. Conversely, these vitamin D metabolites also assist in mobilizing calcium and phosphate from bone and likely increase the reabsorption of calcium and perhaps also of phosphate via the renal tubules. There exists a period of 10 to 24 hours between the administration of cholecalciferol and the initiation of its action in the body due to the necessity of synthesis of the active vitamin D metabolites in the liver and kidneys. It is parathyroid hormone that is responsible for the regulation of such metabolism at the level of the kidneys.

Mechanism of action

The mechanism of action of glucosamine in joint health is unclear, however there are several possible mechanisms that contribute to its therapeutic effects. Because glucosamine is a precursor for glycosaminoglycans, and glycosaminoglycans are a major component of joint cartilage, glucosamine supplements may help to rebuild cartilage and treat the symptoms of arthritis. Some in vitro studies show evidence that glucosamine reduces inflammation via inhibition of interferon gamma and Nuclear factor kappa B subunit 65 (NF-κB p65), improving the symptoms of arthritis and joint pain. Clinical relevance is unknown at this time. When taken up by living cells, glucosamine reacts with ATP to form glucosamine-6-phosphate, the natural precursor of glycosaminoglycans (GAGs) that contain N-acetylglucosamine (keratan sulfate and Hyaluronan) and those that have N-acetylgalactosamine (heparan sulfate and chondroitin sulfate). These GAGs are polysaccharides composed of hexosamines and monosaccharides (e.g., galactose and glucuronic acid) arranged as a linear chain of repeating disaccharide units (such as the glucuronic acid and N-acetylgalactosamine-6-sulfate of chondroitin sulfate). With the exception of hyaluronan, GAGs do not exist alone in nature but are attached to specific "core" proteins, and the composite structures are called proteoglycans (protein-glycosaminoglycans). Both hyaluronan and many different kinds of proteoglycans (such as aggrecan, versican, and syndecan) are abundant throughout the body where they perform diverse functions.

Pharmacodynamics

The administration of glucosamine, in theory, provides a building block towards the synthesis of glycosaminoglycans, slowing the progression of osteoarthritis and relieving symptoms of joint pain. Studies to this date examining the efficacy of glucosamine sulfate have been inconclusive. Glycosaminoglycans contribute to joint cartilage elasticity, strength, and flexibility. A systematic review of various studies and guidelines determined that modest improvements were reported for joint pain and function in patients taking glucosamine. A consistent joint space narrowing was observed, but with an unclear clinical significance.