HEPAROL PLUS ORAL SOLUTION (Each ml contains: Sorbitol/ L-Carnitine/ Betaine HCL/ Choline Chloride/ D-Panthenol/ Magnesium Sulphate/ DL-methionine/ Vitamin C 200mg/ 50mg/ 12.5mg/ 200mg/ 25mg/ 100mg/ 7.5mg/ 0.5mg )

Indications

• Homocystinuria
• Type I Gaucher's disease (specialist use only)

Dosage

Children: Refer to BNF for Children for specific dosing guidelines.

Adults: Refer to BNF for specific dosing guidelines.

Mechanism of action

Betaine acts as a methyl donor in the transsulfuration pathway, facilitating the conversion of homocysteine to methionine and thereby reducing homocysteine levels.

Pharmacodynamics

Betaine reduces plasma homocysteine concentrations, which is beneficial in conditions such as homocystinuria. It also has a role in osmoregulation and may influence cellular metabolism.

Pharmacokinetics

Betaine is well absorbed after oral administration, with a bioavailability of approximately 90%. It is primarily excreted in the urine as betaine and its metabolites.

Adverse effects

• abdominal discomfort
• agitation
• alopecia
• appetite decreased
• brain oedema
• diarrhoea
• glossitis
• irritability
• nausea
• skin reactions
• urinary incontinence
• vomiting
• arthralgia
• asthenia
• chest discomfort
• dizziness
• dyspnoea
• fever
• flushing
• gastrointestinal discomfort
• headache
• hypersensitivity
• hypertension
• hypotension
• infusion-related reactions
• nausea
• pain
• skin reactions
• tachycardia

Interactions

• may be given with supplements of Vitamin B12, pyridoxine, and folate under specialist advice

Precautions

• use in conjunction with dietary restrictions
• monitor plasma-methionine concentration before and during treatment
• interrupt treatment if symptoms of cerebral oedema occur
• use with caution in pregnancy due to limited information
• use with caution in breastfeeding due to lack of information

Pregnancy

Manufacturer advises avoid unless essential-limited information available.

Breast-feeding

Manufacturer advises caution-no information available.

Storage

Store in a cool, dry place; protect from light.

Formulations

• Cystadane oral powder 1 gram per 1 gram

Indications

• Vitamin C deficiency
• Scurvy
• Adjunct therapy in iron overload conditions

Dosage

Children: Child 1 month–3 years: 125–250 mg daily in 1–2 divided doses; Child 4–11 years: 250–500 mg daily in 1–2 divided doses; Child 12–17 years: 0.5–1 g daily in 1–2 divided doses.

Adults: 500 mg daily, taken in 1-2 divided doses, depending on the clinical condition and dietary needs.

Mechanism of action

Ascorbic acid functions primarily as a reducing agent, facilitating enzymatic reactions in the body, including the hydroxylation of proline and lysine in collagen synthesis. It also plays a role in the absorption of iron from the gastrointestinal tract and enhances the immune response.

Pharmacodynamics

Ascorbic acid is crucial for the maintenance of connective tissue and is involved in the metabolism of several amino acids. Its antioxidant properties help to mitigate oxidative stress and may play a role in reducing the risk of chronic diseases.

Pharmacokinetics

Ascorbic acid is absorbed in the intestines and is widely distributed throughout the body. The renal clearance of ascorbic acid is dose-dependent, with higher doses leading to increased excretion. The half-life varies but is generally around 15 to 30 minutes in healthy individuals, with tissue saturation levels influencing its retention.

Contra-indications

• Hypercalcaemia
• Hyperoxaluria
• Patients with cardiac dysfunction

Adverse effects

• Abdominal pain
• Headache
• Nausea
• Vomiting
• Diarrhoea
• Constipation
• Weight loss
• Polyuria
• Sweating
• Thirst
• Vertigo

Interactions

• Increases risk of cardiovascular adverse effects with iron chelators
• Increases risk of cardiovascular adverse effects with deferiprone
• Increases risk of cardiovascular adverse effects with desferrioxamine

Precautions

• Use with caution in patients with iron overload
• Monitor for symptoms of overdose

Pregnancy

High doses teratogenic in animals but therapeutic doses unlikely to be harmful.

Storage

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

Formulations

• Ascorbic acid 50 mg tablets
• Ascorbic acid 100 mg tablets
• Ascorbic acid 200 mg tablets
• Ascorbic acid 250 mg tablets
• Ascorbic acid 500 mg capsules

Indications

• Choline deficiency
• Support in liver function
• Neurological health, including cognitive function
• Fat metabolism disorders

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines.

Adults: Refer to the BNF for specific dosing guidelines.

Mechanism of action

Choline is a major component of phosphatidylcholine, which is essential for maintaining cell membrane integrity, facilitating information flow, and intracellular communication. It is involved in the synthesis of acetylcholine, a key neurotransmitter in the central nervous system. Choline deficiency can lead to apoptosis by affecting cell membrane composition and increasing ceramide levels, which activates apoptotic pathways. Additionally, choline is a precursor to betaine, which helps regulate homocysteine levels, thus reducing cardiovascular risks.

Pharmacodynamics

Choline is crucial for proper nerve conduction in the central nervous system as it is a precursor for acetylcholine. It supports liver function, gallbladder regulation, and lipid metabolism. Adequate choline levels are associated with the prevention of excessive fat accumulation in the liver and may mitigate conditions such as Parkinsonism and tardive dyskinesia. Deficiencies can lead to serious health problems, including liver dysfunction and stunted growth.

Pharmacokinetics

Choline is absorbed in the intestines and distributed throughout the body, where it is utilized in various metabolic pathways. The liver plays a central role in choline metabolism, converting it into phosphatidylcholine and other metabolites. The half-life and excretion pathways of choline are not well defined but are influenced by dietary intake, physiological state, and individual metabolism.

Interactions

• corticosteroids+cholinesalicylate: Unknown (decreases concentration)

Pregnancy

Choline is generally considered safe during pregnancy, as it is essential for fetal development, particularly for brain development and function. However, it is important to adhere to recommended dietary allowances.

Breast-feeding

Choline is important during breastfeeding as it supports infant brain development. Adequate intake is recommended for nursing mothers.

Storage

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

Indications

• Topical treatment of skin wounds
• Moisturizing dry skin
• Management of minor burns
• Soothing irritations and inflammation of the skin

Dosage

Children: Refer to the BNF for Children for specific dosing

Adults: Apply to the affected area as needed, following the specific product instructions.

Mechanism of action

Dexpanthenol is enzymatically converted to pantothenic acid, which is integral to the formation of coenzyme A. This coenzyme acts as a cofactor in numerous enzymatic reactions, particularly those related to protein metabolism in epithelial tissues. The topical application of dexpanthenol promotes fibroblast proliferation and accelerates wound healing through enhanced re-epithelialization. It also increases the availability of coenzyme A for acetylcholine synthesis, which can enhance intestinal motility by improving peristalsis.

Pharmacodynamics

Dexpanthenol, through its conversion to pantothenic acid, plays a vital role in the synthesis of coenzyme A, which is necessary for various metabolic processes, including the transfer of acetyl groups. It directly influences the production of acetylcholine, the neurotransmitter responsible for parasympathetic nervous system functions, which include maintaining normal intestinal activity. A deficiency in acetylcholine can lead to reduced peristalsis and conditions such as adynamic ileus.

Pharmacokinetics

Dexpanthenol is well absorbed when applied topically. It penetrates the skin effectively, reaching the underlying tissues where it can exert its biological effects. The metabolism of dexpanthenol involves its conversion to pantothenic acid, which further participates in the synthesis of coenzyme A. The elimination half-life and extent of systemic absorption vary based on the formulation and route of administration, but topical use typically results in low systemic exposure.

Adverse effects

• Skin irritation
• Allergic reactions

Precautions

• Use with caution in patients with known allergies to dexpanthenol or related compounds.

Pregnancy

Dexpanthenol is generally considered safe for use during pregnancy, but it is advisable to consult a healthcare provider before use.

Breast-feeding

Dexpanthenol is considered safe during breastfeeding, but consult a healthcare provider for specific recommendations.

Storage

Store at room temperature, away from light and moisture. Keep out of reach of children.

Formulations

• Topical cream
• Topical ointment
• Topical solution

Indications

• Vitamin B12 disorders
• Amino acid transport defects

Dosage

Children: Refer to the BNF for Children for specific dosing information.

Adults: Refer to the BNF for specific dosing information.

Mechanism of action

Dlmethionine acts as a methyl donor in various biochemical pathways, facilitating the transfer of methyl groups in reactions crucial for DNA synthesis and repair, as well as the metabolism of neurotransmitters. It is involved in the synthesis of S-adenosylmethionine (SAMe), which is a key methyl donor in numerous biological processes. Additionally, it may play a role in antioxidant defense mechanisms and cellular redox homeostasis.

Pharmacodynamics

The pharmacodynamic effects of dlmethionine are primarily related to its role in protein synthesis and methylation processes. By contributing to methylation, it influences gene expression and cellular function. Dlmethionine may also have protective effects against oxidative stress, enhancing cellular resilience and contributing to overall metabolic health.

Pharmacokinetics

Dlmethionine is absorbed from the gastrointestinal tract following oral administration, with peak plasma concentrations typically occurring within a few hours. It is metabolized in the liver and other tissues, where it can be converted into various metabolites, including S-adenosylmethionine. The elimination half-life and specific excretion pathways are not well characterized, necessitating further research to fully understand its pharmacokinetic profile.

Pregnancy

Safety during pregnancy has not been established. Use only if clearly needed and after assessing the benefits versus risks.

Breast-feeding

Caution is advised when administering to breastfeeding mothers. It is recommended to weigh the potential benefits against possible risks.

Storage

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

Mechanism of action

Levocarnitine acts as a carrier molecule for long-chain fatty acids, transporting them into mitochondria for beta-oxidation, which is critical for energy production. It also exports acyl groups from subcellular organelles and cells to urine, preventing toxic accumulation. The mechanism of action includes interactions with carnitine transporters, translocases, and acetyltransferases. Additionally, it normalizes the brain's redox state and enhances urea synthesis in the liver, potentially activating the glucocorticoid receptor. L-carnitine's antagonistic effects on thyroid hormone action, including inhibiting its nuclear entry, contribute to its therapeutic applications.

Pharmacodynamics

Levocarnitine plays a significant role in lipid metabolism and energy production through its involvement in the transport of fatty acids into the mitochondria. A deficiency in carnitine can lead to various metabolic issues, including liver, heart, and muscle dysfunction. The therapeutic use of levocarnitine includes its ability to stimulate gastric and pancreatic secretions and treat hyperlipoproteinemias. The L-isomer of carnitine is specifically active in lipid metabolism, and its deficiency can be identified through biochemical markers such as low plasma concentrations of free carnitine and elevated acylcarnitine levels.

Pharmacokinetics

Levocarnitine is absorbed in the intestines and distributed throughout the body tissues. It is primarily metabolized in the liver, with excretion occurring via urine. The pharmacokinetics of levocarnitine can vary based on dietary intake, physiological status, and specific health conditions that may affect its metabolism and clearance. The bioavailability of levocarnitine may also be

Adverse effects

• Nausea
• Vomiting
• Abdominal cramps
• Diarrhea
• Fishy body odor
• Rash
• Seizures (rare)

Interactions

• Anticoagulants may have altered effects.
• Thyroid hormones may have altered action due to L-carnitine's peripheral antagonism.

Precautions

• Use with caution in patients with renal impairment.
• Monitor for potential interactions with other medications.

Pregnancy

Limited data is available on the use of levocarnitine during pregnancy. Use only if clearly needed and after assessing benefits versus risks.

Breast-feeding

Levocarnitine is excreted in human milk. Caution is advised when administered to nursing mothers.

Storage

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

Formulations

• Oral solution
• Tablets
• Capsules

Indications

• Constipation
• Diagnostic aid in colonoscopy preparation
• Management of hyperosmolality in various conditions

Dosage

Children: For children, the dosage should be determined based on age and condition, and it is advised to refer to the BNF for Children for specific dosing guidelines.

Adults: The typical dose for adults is 30 to 150 mL of sorbitol solution (70%) taken orally, as needed, usually before bedtime.

Mechanism of action

Sorbitol exerts its laxative effect by drawing water into the large intestine, thereby stimulating bowel movements. It acts as a hygroscopic agent, pulling water from tissues into the feces, which reflexively stimulates evacuation. In metabolic pathways, sorbitol is produced from glucose via aldose reductase and is converted to fructose by sorbitol dehydrogenase, with implications in diabetic complications such as retinopathy.

Pharmacodynamics

Sorbitol's laxative effect results from its osmotic properties, which increase the water content of the stool and soften it, facilitating easier passage. Additionally, sorbitol can induce apoptosis in certain cancer cell lines, indicating potential therapeutic implications beyond its laxative use. The modulation of intracellular signaling pathways through the regulation of proteins such as Bax and Bcl-2 suggests a complex role in cellular health and disease.

Pharmacokinetics

Sorbitol is poorly absorbed in the gastrointestinal tract, which contributes to its efficacy as a laxative. It is metabolized in the liver, primarily through the polyol pathway. The absorption and distribution of sorbitol are affected by its osmotic properties, leading to increased intestinal water retention. Its elimination is primarily via renal excretion, with minimal systemic absorption, thus reducing the risk of systemic side effects.

Adverse effects

• Diarrhea
• Abdominal cramps
• Nausea
• Vomiting
• Electrolyte imbalances

Precautions

• Use with caution in patients with renal impairment
• May exacerbate gastrointestinal conditions

Pregnancy

Sorbitol is generally considered safe during pregnancy, but should be used under medical supervision.

Breast-feeding

Sorbitol is excreted in breast milk in small amounts; consult a healthcare provider before use.

Storage

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

Formulations

• Oral solution
• Syrup

Mechanism of action

Homocystinuria is a hereditary disorder characterized by high levels of the amino acid homocysteine. This condition can be caused by deficiencies or defects in cystathionine beta-synthase (CBS), 5,10-methylenetetrahydrofolate reductase (MTHFR), and cobalamin cofactor metabolism (cbl). CBS converts homocysteine to cystathionine, and a deficiency in this enzyme can lead to an accumulation of homocysteine. MTHFR is responsible for producing 5-methyltetrahydrofolate, a methyl donor that participates in the conversion of homocysteine back to methionine; therefore, an MTHFR deficiency can also lead to homocystinuria. Additionally, a defect in cobalamin (vitamin B12) cofactor metabolism can lead to homocystinuria, since a metabolite of cobalamin (methylcobalamin) promotes the conversion of homocysteine to methionine. Betaine transfers a methyl group via the enzyme betaine homocysteine methyl transferase (BHMT), converting homocysteine back into methionine and dimethylglycine (DMG). In patients with homocystinuria, betaine reduces homocysteine levels and improves health outcomes. Betaine acts as metabolic intermediate in transmethylating processes (creatine and methionine synthesis). Betaine acts as a methyl group donor in the remethylation of homocysteine to methionine in patients with homocystinuria. This reduces toxic concentrations of homocysteine, usually to 20 to 30% or less of pretreatment concentrations. Betaine or trimethylglycine is a quarternary ammonium compound that was first discovered in the juice of sugar beets (Beta vulgaris). Betaine is a metabolite of choline ... and is a substrate in one of the two recycling pathways that convert homocysteine to L-methionine. The other and principal recycling reaction is catalyzed by the enzyme methionine synthase and uses methylcobalamin as a cofactor and 5-methyltetrahydrofolate as a cosubstrate. Betaine-homocysteine methyltransferase (BHMT) is a zinc metalloenzyme which catalyzes the transfer of a methyl group from betaine to homocysteine in the formation of methionine. BHMT is found in the liver and kidneys and may also exist in brain tissue. Betaine acts to lower homocysteine levels in some with primary hyperhomocysteinemia/homocystinuria via this enzyme.

Pharmacodynamics

Betaine decreases plasma homocysteine concentrations in homocystinuria cases caused by deficiencies or defects in cystathionine beta-synthase (CBS), 5,10-methylenetetrahydrofolate reductase (MTHFR), and cobalamin cofactor metabolism (cbl). The decrease of homocysteine is estimated to be 20-30% of pre-treatment levels. Betaine supplementation in patients with homocystinuria also improves metabolic abnormalities in cerebrospinal fluid. Reports have shown that depending on the type of homocystinuria, the therapeutic effectiveness of betaine alone may be limited, insufficient to decrease total homocysteine levels and prevent clinical symptoms. In patients with homocystinuria due to cystathionine beta-synthase (CBS) deficiency, betaine should be used when serum total homocysteine levels remain high despite dietary therapy. Patients taking betaine for several years do not show evidence of tolerance. Also, betaine concentrations are not correlated with homocysteine concentrations. In patients with MTHFR deficiency and cbl defects, betaine may increase methionine and S-adenosyl methionine (SAM) plasma levels. Patients with CBS deficiency without a dietary restriction of methionine may accumulate excessive amounts of methionine. Clinical data shows that in patients with CBS deficiency, increased plasma methionine levels were associated with cerebral edema.

Mechanism of action

Choline is a major part of the polar head group of phosphatidylcholine. Phosphatidylcholine's role in the maintenance of cell membrane integrity is vital to all of the basic biological processes: information flow, intracellular communication and bioenergetics. Inadequate choline intake would negatively affect all these processes. Choline is also a major part of another membrane phospholipid, sphingomyelin, also important for the maintenance of cell structure and function. It is noteworthy and not surprising that choline deficiency in cell culture causes apoptosis or programmed cell death. This appears to be due to abnormalities in cell membrane phosphatidylcholine content and an increase in ceramide, a precursor, as well as a metabolite, of sphingomyelin. Ceramide accumulation, which is caused by choline deficiency, appears to activate Caspase, a type of enzyme that mediates apoptosis. Betaine or trimethylglycine is derived from choline via an oxidation reaction. Betaine is one of the factors that maintains low levels of homocysteine by resynthesizing L-methionine from homocysteine. Elevated homocysteine levels are a significant risk factor for atherosclerosis, as well as other cardiovascular and neurological disorders. Acetylcholine is one of the major neurotransmitters and requires choline for its synthesis. Adequate acetylcholine levels in the brain are believed to be protective against certain types of dementia, including Alzheimer's disease.

Pharmacodynamics

This compound is needed for good nerve conduction throughout the CNS (central nervous system) as it is a precursor to acetylcholine (ACh). Choline is also needed for gallbladder regulation, liver function and lecithin (a key lipid) formation. Choline also aids in fat and cholesterol metabolism and prevents excessive fat build up in the liver. Choline has been used to mitigate the effects of Parkinsonism and tardive dyskinesia. Choline deficiencies may result in excessive build-up of fat in the liver, high blood pressure, gastric ulcers, kidney and liver dysfunction and stunted growth.

Mechanism of action

Dexpanthenol is an alcohol derivative of pantothenic acid, a component of the B complex vitamins and an essential component of a normally functioning epithelium. Dexpanthenol is enzymatically cleaved to form pantothenic acid, which is an essential component of Coenzyme A, which acts as a cofactor in many enzymatic reactions that are important for protein metabolism in the epithelium. Dermatological effects of the topical use of dexpanthenol include increased fibroblast proliferation and accelerated re-epithelialization in wound healing. Furthermore, it acts as a topical protectant, moisturizer, and has demonstrated anti-inflammatory properties. This alcohol ... is said to increase the amount of coenzyme A available for the synthesis of acetylcholine. Increased formation of acetylcholine is thought to increase peristalsis and intestinal tone. ... To test the functional effect of pantothenate on dermal fibroblasts, cells were cultured and in vitro proliferation tests were performed using a standardized scratch test procedure. For all three donors analyzed, a strong stimulatory effect of pantothenate at a concentration of 20 ug/mL on the proliferation of cultivated dermal fibroblasts was observed. To study the molecular mechanisms resulting in the proliferative effect of pantothenate, gene expression was analyzed in dermal fibroblasts cultivated with 20 ug/mL of pantothenate compared with untreated cells using the GeneChip Human Exon 1.0 ST Array. A number of significantly regulated genes were identified including genes coding for interleukin (IL)-6, IL-8, Id1, HMOX-1, HspB7, CYP1B1 and MARCH-II. Regulation of these genes was subsequently verified by quantitative real-time polymerase chain reaction analysis. Induction of HMOX-1 expression by pantothenol and pantothenic acid in dermal cells was confirmed on the protein level using immunoblots. Functional studies revealed the enhanced suppression of free radical formation in skin fibroblasts cultured with panthenol. In conclusion, these studies provided new insight in the molecular mechanisms linked to the stimulatory effect of pantothenate and panthenol on the proliferation of dermal fibroblasts. /Calcium pantotenate/ ... Pantothenic acid, pantothenol and other derivatives ... are precursors of CoA /that/ protect cells and whole organs against peroxidative damage by increasing the content of cell glutathione...

Pharmacodynamics

Pantothenic acid is a precursor of coenzyme A, which serves as a cofactor for a variety of enzyme-catalyzed reactions involving transfer of acetyl groups. The final step in the synthesis of acetylcholine consists of the choline acetylase transfer of acetyl group from acetylcoenzyme A to choline. Acetylcholine is the neurohumoral transmitter in the parasympathetic system and as such maintains the normal functions of the intestine. Decrease in acetylcholine content would result in decreased peristalsis and in extreme cases adynamic ileus.

Mechanism of action

Levocarnitine can be synthesised within the body from the amino acids lysine or methionine. Vitamin C (ascorbic acid) is essential to the synthesis of carnitine. Levocarnitine is a carrier molecule in the transport of long chain fatty acids across the inner mitochondrial membrane. It also exports acyl groups from subcellular organelles and from cells to urine before they accumulate to toxic concentrations. Only the L isomer of carnitine (sometimes called vitamin BT) affects lipid metabolism. Levocarnitine is handled by several proteins in different pathways including carnitine transporters, carnitine translocases, carnitine acetyltransferases and carnitine palmitoyltransferases. L-Carnitine is a peripheral antagonist of thyroid hormone action in some tissues. It inhibits thyroid hormone entry into cell nuclei. In a controlled clinical trial, L-carnitine was shown to reverse or prevent some symptoms of hyperthyroidism. ... Mortality and metabolic consequences of acute ammonium intoxication in mice are reduced by pharmacologic admin of L-carnitine. The mechanism for this effect may have 2 components. L-Carnitine admin normalizes the redox state of the brain (perhaps by incr the avail of beta-hydroxybutyrate and/or acetyl-L-carnitine to the brain), and it incr the rate of urea synth in the liver, perhaps in part by activation of the glucocorticoid receptor. At least part of the protective effect is associated with flux through the carnitine acyltransferases, as analogs of L-carnitine that are competitive inhibitors of carnitine acyltransferases enhance the toxicity of acute ammonium admin. Thus, it has been proposed that L-carnitine incr urea synth in the liver by facilitating fatty acid entry into mitochondria, leading to incr flux through the beta-oxidation pathway, an incr of intramitochondrial reducing equivalents, and enhancement of ATP production. ... Levocarnitine is necessary for normal mammalian fat utilization and energy metabolism. It facilitates entry of long-chain fatty acids into cellular mitochondria, where they are used during oxidation and energy production. It also exports acyl groups from subcellular organelles and from cells to urine before they accumulate to toxic concentrations. Carnitine's primary mechanism of action is apparently attributable to its role as a cofactor in the transformation of free long-chain fatty acids into acylcarnitines for subsequent transport into the mitochondrial matrix. Carnitine is involved in the metabolism of ketones for energy and the conversion of branched-chain amino acids - valine, leucine, and isoleucine - into energy. /Carnitine/ L-Carnitine participates in a reversible transesterification reaction, in which an acyl group is transferred from coenzyme A to the hydroxyl group of L-carnitine ... /This reaction facilitates the/ transfer of long-chain fatty acids from cytoplasm ... /and/ chain-shortened /very-long-chain/ fatty acids from peroxisomes to mitochondria /and the/ modulation of the acyl-CoA/CoA ratio in cellular compartments.

Pharmacodynamics

Levocarnitine is a carrier molecule in the transport of long chain fatty acids across the inner mitochondrial membrane. It also exports acyl groups from subcellular organelles and from cells to urine before they accumulate to toxic concentrations. Lack of carnitine can lead to liver, heart, and muscle problems. Carnitine deficiency is defined biochemically as abnormally low plasma concentrations of free carnitine, less than 20 µmol/L at one week post term and may be associated with low tissue and/or urine concentrations. Further, this condition may be associated with a plasma concentration ratio of acylcarnitine/levocarnitine greater than 0.4 or abnormally elevated concentrations of acylcarnitine in the urine. Only the L isomer of carnitine (sometimes called vitamin BT) affects lipid metabolism. The "vitamin BT" form actually contains D,L-carnitine, which competitively inhibits levocarnitine and can cause deficiency. Levocarnitine can be used therapeutically to stimulate gastric and pancreatic secretions and in the treatment of hyperlipoproteinemias.

Mechanism of action

Sorbitol exerts its laxative effect by drawing water into the large intestine, thereby stimulating bowel movements. ... Sorbitol exerts hygroscopic and/or local irritant action, drawing water from tissues into feces and reflexly stimulating evacuation. The polyol pathway consists of two enzymes aldose reductase (AR) and sorbitol dehydrogenase (SDH); the former is the first enzyme in the polyol pathway, that catalyzes the reduction of glucose to sorbitol, the latter is the second one, that converts sorbitol to fructose using by NAD(+) as a cofactor. ... SDH activity, the second step in the polyol pathway, might make a greater contribution to the etiology of diabetic retinopathy than does the first step involving AR. /This paper proposes/ a novel hypothesis that polymorphisms of SDH gene may be correlated with SDH gene expression levels in diabetic retinas, thus being a valuable genetic marker for diabetic retinopathy. It has been reported that sorbitol induces apoptosis in several cancer cell lines. ... In /this/ study, the intracellular signaling pathways of sorbitol-induced apoptosis in human K562 cells were investigated using both morphological analysis and DNA fragmentation technique. In this study, we demonstrated that sorbitol-induced apoptosis in human K562 cells is a concentration- and time-dependent manner. This sorbitol-induced apoptosis in human K562 cells was also accompanied by the up-regulation of Bax, and down-regulation of p-Bcl-2, but no effect on the levels of Bcl-X(L). Moreover, the sorbitol treatment resulted in a significant reduction of mitochondria membrane potential, increase in the release of mitochondrial cytochrome c (cyt c), and activation of caspase 3. Furthermore, treatment with caspase 3 inhibitor (z-DEVD-fmk) was capable of preventing the sorbitol-induced caspase 3 activity and cell death. These results clearly demonstrate that the induction of apoptosis by sorbitol involves multiple cellular/molecular pathways and strongly suggest that pro- and anti-apoptotic Bcl-2 family proteins, mitochondrial membrane potential, mitochondrial cyt c, and caspase 3, they all participate in sorbitol-induced apoptotic process in human K562 cells. Chronic diabetic complications, in particular, nephropathy, peripheral and autonomic neuropathy, "diabetic foot," retinopathy, and cardiovascular disease, remain the major cause of morbidity and mortality in patients with diabetes mellitus. Growing evidence indicates that both increased activity of the sorbitol pathway of glucose metabolism and enhanced oxidative stress are the leading factors in the pathogenesis of diabetic complications. The relation between the two mechanisms remains the area of controversy. One group has reported that increased sorbitol pathway activity has a protective rather than detrimental role in complication-prone tissues because the pathway detoxifies toxic lipid peroxidation products. Others put forward a so-called "unifying hypothesis" suggesting that activation of several major pathways implicated in diabetic complications (eg, sorbitol pathway) occurs due to increased production of superoxide anion radicals in mitochondria and resulting poly(ADP-ribose) polymerase activation. This review (a) presents findings supporting a key role for the sorbitol pathway in oxidative stress and oxidative stress-initiated downstream mechanisms of diabetic complications, and (b) summarizes experimental evidence against a detoxifying role of the sorbitol pathway, as well as the "unifying concept."