PSORIASONE

Indications

• Suppression of inflammatory disorders
• Management of allergic conditions
• Congenital adrenal hyperplasia
• Inflammatory and allergic eye conditions

Dosage

Children: For children aged 1–11 months: Initially 1 mg, repeated up to 4 times in 24 hours according to response. Aged 1–5 years: Initially 2 mg, repeated up to 4 times in 24 hours according to response. Aged 6–11 years: Initially 4 mg, repeated up to 4 times in 24 hours according to response. Aged 12–17 years: 4–20 mg, repeated up to 4 times in 24 hours according to response.

Adults: Dosage varies based on condition; typically, initial doses are adjusted according to the patient's response and severity of condition.

Mechanism of action

Betamethasone exerts its effects by binding to glucocorticoid receptors, leading to modulation of gene expression and suppression of inflammatory cytokines and mediators.

Pharmacodynamics

Betamethasone reduces inflammation and immune response, which is beneficial in managing various inflammatory and allergic disorders.

Pharmacokinetics

Betamethasone is rapidly absorbed after administration, with a long half-life allowing for once-daily dosing in many cases. It is metabolized in the liver and excreted primarily in urine.

Adverse effects

• Hiccups
• Oedema
• Mood and behaviour changes
• Vision disorders
• Serious gastro-intestinal effects
• Musculoskeletal effects
• Ophthalmic effects
• Stevens-Johnson syndrome
• Myocardial rupture (following recent myocardial infarction)

Interactions

• Cobicistat + betamethasone: Unknown (increases exposure)
• Idelalisib + betamethasone: Unknown (increases exposure)
• Clarithromycin + betamethasone: Unknown (increases exposure)

Precautions

• Immunosuppression due to prolonged corticosteroid treatment
• Adrenal suppression if given for longer than 3 weeks
• Increased susceptibility to infections, including chickenpox and measles

Pregnancy

Readily crosses the placenta. Transient effect on fetal movements and heart rate.

Storage

Store at room temperature, protect from light.

Formulations

• Betamethasone sodium phosphate 4 mg per 1 ml solution for injection ampoules

Indications

• Plaque psoriasis
• Mild to moderate plaque psoriasis
• Scalp psoriasis

Dosage

Children: For children aged 6–11 years, apply twice daily, with a maximum total calcipotriol of 2.5 mg in any one week. For children aged 12–17 years, apply twice daily, not exceeding 3.75 mg in any one week.

Adults: Apply calcipotriol ointment or scalp solution to the affected areas twice daily. Maximum total calcipotriol dosage should not exceed 5 mg per week.

Mechanism of action

Calcipotriol binds to vitamin D receptors in skin cells, leading to the regulation of gene expression involved in cell proliferation and differentiation. This action promotes the normal maturation of keratinocytes and reduces hyperproliferation, which is a hallmark of psoriatic lesions. Additionally, it exhibits anti-inflammatory properties, further aiding in the management of psoriasis.

Pharmacodynamics

Calcipotriol has a dose-dependent effect on keratinocyte proliferation and differentiation. It decreases the production of pro-inflammatory cytokines and chemokines, which are elevated in psoriasis. The therapeutic effects are typically observed within a few weeks of treatment, with optimal results often seen after sustained use. Side effects may include local skin irritation and an increased risk of hypercalcemia, especially if used excessively.

Pharmacokinetics

When applied topically, calcipotriol is minimally absorbed through intact skin. Systemic absorption can occur, particularly when applied to large areas or under occlusion. The half-life of calcipotriol is approximately 1.5 hours in systemic circulation, but its effects persist due to its action on skin cells. The drug is metabolized primarily in the liver, with metabolites excreted through urine and feces.

Contra-indications

• Calcium metabolism disorders
• Erythrodermic exfoliative psoriasis
• Generalised pustular psoriasis
• Do not apply under occlusion

Adverse effects

• Skin reactions
• Hypercalcaemia
• Hypercalciuria
• Photosensitivity reactions
• Increased risk of infection

Interactions

• Acitretin

Precautions

• Avoid excessive exposure to sunlight
• Avoid broken or inflamed skin
• Caution in patients with renal impairment
• Caution in patients with hepatic impairment

Pregnancy

Manufacturers advise avoidance unless essential.

Breast-feeding

No information available.

Storage

Store in a cool, dry place away from light.

Formulations

• Calcipotriol 50 micrograms/g ointment
• Calcipotriol scalp solution

Indications

• Eczema
• Psoriasis
• Contact dermatitis
• Seborrheic dermatitis
• Atopic dermatitis

Dosage

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

Adults: Refer to relevant clinical guidelines or product information for specific dosing instructions.

Mechanism of action

Betamethasone dipropionate exerts its effects by binding to the glucocorticoid receptor, leading to the modulation of gene expression. This interaction results in the inhibition of pro-inflammatory cytokines, chemokines, and adhesion molecules, which reduces inflammation, suppresses the immune response, and promotes vasoconstriction in the affected tissues.

Pharmacodynamics

The pharmacodynamic effects of betamethasone dipropionate include a significant reduction in inflammation and immune response due to the inhibition of leukocyte infiltration at the site of inflammation. The drug also inhibits the release of arachidonic acid, subsequently decreasing the production of inflammatory mediators such as prostaglandins and leukotrienes. Its efficacy is enhanced by its high lipid solubility, allowing for better penetration through the skin layers.

Pharmacokinetics

Betamethasone dipropionate is well absorbed through the skin when applied topically. Its bioavailability is influenced by the formulation and the condition of the skin. The drug is metabolized primarily in the liver to inactive metabolites, which are excreted in the urine. The systemic absorption and effects are minimal when used as directed, but caution is advised in extensive applications or occlusive dressings, which may increase absorption.

Adverse effects

• Local skin atrophy
• Striae
• Telangiectasia
• Hypopigmentation
• Allergic contact dermatitis
• Systemic effects with prolonged use

Precautions

• Use with caution in patients with a history of diabetes mellitus
• Monitor for potential adrenal suppression with prolonged use
• Avoid application to infected areas unless treated

Pregnancy

Betamethasone dipropionate should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Limited data suggest that topical corticosteroids have low systemic absorption.

Breast-feeding

Caution is advised when using betamethasone dipropionate during breastfeeding, as it is unknown whether it is excreted in breast milk. Topical corticosteroids should be applied sparingly and avoided on the breast area to minimize ingestion by the infant.

Storage

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

Formulations

• Topical cream
• Topical ointment
• Topical lotion

Indications

• General anesthesia
• Induction of anesthesia
• Sedation in surgical procedures

Dosage

Children: Refer to the BNF for Children for specific dosing information based on age and weight.

Adults: Dosage varies depending on the procedure and patient characteristics; refer to specific clinical guidelines.

Mechanism of action

The exact mechanism of action of diethyl ether is not completely understood. It is believed to produce reversible loss of consciousness through interactions with membrane lipids and hydrophobic regions of membrane-bound proteins. The drug may alter the function of ion channel proteins, potentially affecting the GABA receptor, which is implicated in the modulation of neuronal excitability. Additionally, ether has been shown to increase plasma levels of adrenaline and noradrenaline, suggesting stimulation of neurosympathetic and adrenomedullary functions.

Pharmacodynamics

Ether induces general anesthesia characterized by a reversible loss of sensation and consciousness. Its anesthetic properties are thought to be the result of its effects on neuronal signaling and neurotransmitter systems, primarily by enhancing inhibitory neurotransmission through GABAergic pathways, leading to decreased neuronal excitability and a sedative effect.

Pharmacokinetics

Diethyl ether is rapidly absorbed through the lungs and is distributed widely in body tissues due to its lipophilicity. It is metabolized primarily in the liver, and elimination occurs through exhalation and minor metabolic pathways. The onset of action is swift, with effects seen within minutes of inhalation, and recovery is equally rapid upon cessation of exposure.

Adverse effects

• Nausea
• Vomiting
• Respiratory depression
• Cardiovascular instability
• Hypotension
• Delayed recovery from anesthesia

Interactions

• May potentiate the effects of other central nervous system depressants
• Increased risk of respiratory depression when used with opioids
• Potential interaction with alcohol, leading to enhanced sedation

Precautions

• Use with caution in patients with respiratory or cardiovascular diseases
• Monitor for signs of respiratory depression
• Ensure appropriate equipment and personnel are available for anesthesia

Pregnancy

Use is contraindicated during pregnancy due to potential risks to the fetus.

Breast-feeding

Use with caution; limited data available on excretion in breast milk.

Storage

Store in a cool, dry place, away from heat and direct sunlight. Keep tightly closed.

Formulations

• Inhalation solution
• Liquid for inhalation

Indications

• Insecticide for agricultural use
• Research tool in toxicology

Dosage

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

Adults: Refer to the BNF for specific dosing and administration guidelines.

Mechanism of action

Methyl parathion acts primarily by inhibiting the enzyme acetylcholinesterase, which is essential for the breakdown of the neurotransmitter acetylcholine. Its active metabolite, methyl paraoxon, is a potent inhibitor of both acetylcholinesterase and butyrylcholinesterase. The inhibition of these enzymes results in the accumulation of acetylcholine at synapses, leading to overstimulation of cholinergic receptors and resultant toxic effects.

Pharmacodynamics

The pharmacodynamics of methyl parathion involve its action as a noncompetitive inhibitor of acetylcholinesterase, causing prolonged effects of acetylcholine due to its inability to be hydrolyzed. The resultant cholinergic toxicity can lead to symptoms such as muscle twitching, respiratory distress, and potentially fatal outcomes if not treated promptly. The extent of inhibition is dose-dependent, with significant toxicity occurring after substantial enzyme inhibition.

Pharmacokinetics

Methyl parathion is absorbed through the gastrointestinal tract and can also be absorbed through the skin and respiratory tract. It is metabolized in the liver to form methyl paraoxon, which is responsible for the majority of its toxic effects. The distribution of methyl parathion in body tissues is influenced by its lipophilicity, and it is primarily excreted as metabolites in the urine. The elimination half-life and specific pharmacokinetic parameters can vary based on individual metabolism and exposure levels.

Pregnancy

There are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is not known whether this drug is excreted in human milk. Caution is advised when administering to nursing women.

Storage

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

Formulations

• Liquid formulation

Indications

• Constipation
• Dry skin
• Skin irritation

Dosage

Children: Refer to specific guidelines and prescribing information for paediatric dosing.

Adults: Refer to specific guidelines and prescribing information for adult dosing.

Mechanism of action

Paraffin acts as a lubricating agent in the gastrointestinal tract. It coats the stool and the intestinal walls, which helps to ease the passage of feces by reducing friction. This action promotes bowel movements and alleviates constipation. When used topically, it forms a barrier on the skin, which helps to retain moisture and protect against irritants.

Pharmacodynamics

Paraffin has a low viscosity and surface tension, which allows it to spread easily over surfaces. Its lubricating properties facilitate the movement of stool through the intestines, while its emollient properties help in maintaining skin hydration and barrier function. The onset of action for oral administration typically occurs within 6 to 8 hours, making it effective in treating occasional constipation.

Pharmacokinetics

Paraffin is not absorbed systemically when ingested; it remains in the gastrointestinal tract and is excreted unchanged in the feces. After oral administration, it acts locally in the intestines without significant systemic effects. When used topically, it remains on the skin surface and does not penetrate deeply, providing a protective layer without altering systemic pharmacokinetics.

Adverse effects

• Abdominal cramps
• Diarrhea
• Nausea
• Vomiting
• Lipid pneumonia (when aspirated)
• Electrolyte imbalances

Precautions

• Use with caution in patients with gastrointestinal obstruction
• Avoid in patients with a history of aspiration
• Monitor for signs of dehydration with prolonged use

Pregnancy

Use only if clearly needed. Consult a healthcare provider for advice.

Breast-feeding

Paraffin can be excreted in breast milk, use with caution.

Storage

Store at room temperature away from moisture and heat.

Formulations

• Liquid paraffin
• Soft paraffin (for topical use)

Indications

• Dry skin conditions
• Cosmetic formulations
• Emollient in topical creams and lotions
• Emulsifying agent in pharmaceutical preparations

Dosage

Children: For pediatric use, refer to specific product formulations and guidelines, as dosing may vary based on the formulation and concentration.

Adults: Stearyl alcohol is used topically in various formulations. Specific dosing is typically determined by the formulation and intended use, refer to product guidelines for detailed instructions.

Mechanism of action

Stearyl alcohol functions primarily as an emollient and emulsifier. It aids in the formation of stable emulsions by reducing the surface tension between oil and water phases, allowing for the creation of creams and lotions. Its hydrophobic tail interacts with lipids, while the hydroxyl group can form hydrogen bonds with water, enhancing moisture retention in the skin.

Pharmacodynamics

Stearyl alcohol acts by providing a protective barrier on the skin, reducing transepidermal water loss and enhancing hydration. Its emollient properties make it effective in softening and smoothing the skin, which can alleviate dryness and improve the overall appearance of the skin. Additionally, it can enhance the delivery of other active ingredients in topical formulations.

Pharmacokinetics

Stearyl alcohol is not significantly absorbed systemically when applied topically. Its primary action is local to the site of application, where it exerts its emollient effects. The compound is metabolized in the body to various fatty acids and alcohols, and it is excreted primarily through the skin and gastrointestinal tract, with minimal systemic exposure.

Pregnancy

Stearyl is generally considered safe for use during pregnancy; however, specific formulations should be evaluated for their ingredients.

Breast-feeding

Stearyl can be used while breastfeeding, but it's recommended to consult a healthcare provider for specific concerns regarding topical applications.

Storage

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

Formulations

• Cream
• Ointment
• Lotion

Mechanism of action

Glucocorticoids inhibit neutrophil apoptosis and demargination, and inhibit NF-Kappa B and other inflammatory transcription factors. They also inhibit phospholipase A2, leading to decreased formation of arachidonic acid derivatives. In addition, glucocorticoids promote anti-inflammatory genes like interleukin-10. Corticosteroids like betamethasone can act through nongenomic and genomic pathways. The genomic pathway is slower and occurs when glucocorticoids activate glucocorticoid receptors and initiate downstream effects that promote transcription of anti-inflammatory genes including phosphoenolpyruvate carboxykinase (PEPCK), IL-1-receptor antagonist, and tyrosine amino transferase (TAT). On the other hand, the nongenomic pathway is able to elicit a quicker response by modulating T-cell, platelet and monocyte activity through the use of existing membrane-bound receptors and second messengers. Corticosteroids interact with specific receptor proteins in target tissues to regulate the expression of corticosteroid responsive genes, thereby changing the levels and array of proteins synthesized by the various target tissues. As a consequence of the time required for changes in gene expression and protein synthesis, most effects of corticosteroids are not immediate, but become apparent after several hours. ... Although corticosteroids predominantly act to increase expression of target genes, there are well documented examples where glucocorticoids decrease transcription of target genes ... In contrast to these genomic effects, recent studies have raised the possibility that some actions of corticosteroids are immediate and are mediated by membrane-bound receptors. /Adrenocorticosteroids/ The mechanisms by which glucocorticoids inhibit glucose utilization in peripheral tissues are not fully understood. Glucocorticoids decrease glucose uptake in adipose tissue, skin, fibroblasts, thymocytes, and polymorphonuclear leukocytes; these effects are postulated to result from translocation of the glucose transporters from the plasma membrane to an intracellular location. These peripheral effects are associated with a number of catabolic actions, including atrophy of lymphoid tissue, decreased muscle mass, negative nitrogen balance, and thinning of the skin. /Adrenocorticalsteroids/ The mechanisms by which the glucocorticoids promote gluconeogenesis are not fully defined. Amino acids mobilized from a number of tissues in response to glucocorticoids reach the liver and provide substrate for the production of glucose and glycogen. In the liver, glucocorticoids induce the transcription of a number of enzymes involved in gluconeogenesis and amino acid metabolism, including phosphoenolpyruvate carboxykinase, glucose-6-phosphatase, and fructose-2,6-bisphosphatase. Analyses of the molecular basis for regulation of phosphoenolpyruvate carboxykinase gene expression have identified complex regulatory influences involving an interplay among glucocorticoids, insulin, glucagon, and catecholamine. The effects of these hormones and amines on phosphoenolpyruvate carboxykinase gene expression mirror the complex regulation of gluconeogenesis in the intact organism. /Adrenocorticalsteroids/ ... /A/ major action of corticosteroids on the cardiovascular system is to enhance vascular reactivity to other vasoactive substances. Hypoadrenalism generally is associated with hypotension and reduced response to vasoconstrictors such as norepinephrine and angiotensin II. This diminished pressor response is explained partly by recent studies in experimental systems showing that glucocorticoids increase expression of adrenergic receptors in the vascular wall. Conversely, hypertension is seen in patients with excessive glucocorticoid secretion, occurring in most patients with Cushing's syndrome and in a subset of patients treated with synthetic glucocorticoids (even those lacking any significant mineralocorticoid action). /Adrenocorticosteroids/ For more Mechanism of Action (

Pharmacodynamics

Corticosteroids bind to the glucocorticoid receptor inhibiting pro-inflammatory signals, while promoting anti-inflammatory signals. Corticosteroids have a wide therapeutic window as patients may require doses that are multiples of what the body naturally produces. Patients who require long-term treatment with a corticosteroid should be counselled regarding the risk of hypothalamic-pituitary-adrenal axis suppression and increased susceptibility to infections.

Mechanism of action

The precise mechanism of calcipotriol in remitting psoriasis is not well-understood, however, it has been shown to have comparable affinity with calcitriol for the Vitamin D receptor while being less than 1% the activity in regulating calcium metabolism. The Vitamin D receptor (VDR) belongs to the steroid/thyroid receptor superfamily, and is found on the cells of many different tissues including the thyroid, bone, kindney, and T cells of the immune system. T cells are known to play a role in psoriasis and are believed to undergo modulation of gene expression with binding of calcipotriol to the VDR. This modulation is thought to affect gene products related to cell differentiation and proliferation.

Pharmacodynamics

Calcipotriene is a synthetic analog of vitamin D. In humans, the natural supply of vitamin D depends mainly on exposure to the ultraviolet rays of the sun for conversion of 7-dehydrocholesterol to vitamin D3 (cholecalciferol) in the skin.

Mechanism of action

The mechanism of action by which .... ethyl ether produce/s/ reversible loss of consciousness is still unclear. Anesthesia can be produced by a wide variety of chemical agents, ranging from inert rare gases to steriodal molecules. This apparent lack of specificity, together with the observation that general anesthesia can be reversed by high pressure, poses a unique pharmacological problem. Most theories concern interaction of anesthetics with either membrane lipids or hydrophobic regions of specificic membrane-bound proteins. One hypothesis is that the anesthetic changes the function of an ion channel protein by modifying the conformation of the protein. Some investigators suggest that the GABA receptor may be the ion channel protein that is affected by inhalation of anesthetic agents... The most appropriate concept for the mechanism of general anesthesia /may be/ a the heterogenous site of anesthetic action, including both lipid and protein membrane components linked with neuronal function. In chronically catheterized rats, diethyl ether increased plasma adrenaline and noradrenaline concentrations indicating that this drug stimulates both neurosympathetic and adrenomedullary functions. These effects appear to be centrally mediated, since ganglionic blockade or spinal transection completely counteracted the diethyl ether induced increases in plasma calcium levels. Hippocampal EEG signals derived from chronically implanted electrodes in the freely moving rat were recorded before and after administration of centrally acting drugs, and analyzed by power and coherence spectra. Diethyl ether induced a low frequency (3-6 c/s) theta power and coherence peak in the immobile rat, which was sensitive to atropine or scopolamine. The residue spectrum, defined as the EEG spectrum with the theta harmonics removed, was sensitive to centrally acting drugs. Diethyl ether suppressed fast waves of 50-100 c/s, and some conditions, enhanced 15-50 c/s waves. The plasma beta-endorphin responses to ether and handling stress were examined in animals of various ages. At each age studied there was a significant, stress-induced elevation of plasma beta-endorphin-like immunoreactivity levels were higher in animals 3,7, and 14 days of age than in adults. Cortical action potential activity is suppressed by ether anesthesia and is not affected when sensory fibers in the sciatic nerve are stimulated. Consequently, ether blocks sensory pathways to the cortex; the blockade occurs even before cortical activity is entirely suspended. In contrast, pentobarbital suppresses activity in the cortex without blocking the sensory path to it during sciatic nerve stimulation.

Mechanism of action

Acute poisoning ... is related to ... inhibiting action on enzyme acetylcholinesterase. Toxic manifestations generally occur only after more than 50% of plasma cholinesterase is inhibited. ... Methyl parathion ... depend on oxidative activation by replacement of thiono-sulfur with oxygen for ... toxicity. Methyl parathion has only a slight inhibitory action on acetylcholinesterase and butyrylcholinesterase, but its active metabolite, methyl paraoxon, is a potent inhibitor of both these enzymes. A study was conducted examining the inhibition of (Ca2+ and Mg2+)-ATPase by parathion (56382) and methyl parathion. Enzyme activity was assessed spectrophotometrically in pig erythrocyte membranes containing calcium2+ (Ca2+) and magnesium2+ and in solubilized membrane preparations incubated with the test agents. The enzyme response to ATP was biphasic. Equations expressing the kinetics of the substrate curves described two classes of the ATP binding active site, one with high affinity and low maximum rate and one with low affinity and high maximum rate. High affinity active sites were stimulated by low ATP concentrations (20 uM), whereas low affinity active sites were stimulated by high ATP levels (2 mM). Parathion and methylparathion dose dependently inhibited enzyme activity; parathion had a greater inhibitory effect than methylparathion. Lineweaver-Burke and Dixon plots indicated noncompetitive inhibition. Parathion and methylparathion induced enzyme inhibition occurred over a range of free calcium ion concentrations (0.5 to 5 mM); the inhibition was significantly greater at lower Ca2+ concentrations (1 to 100 uM) than at higher concentrations. The authors conclude that parathion and methylparathion inhibit ATPase activity by binding to a site on the enzyme rather than through an interaction with associated lipids. For more Mechanism of Action (Complete) data for METHYL PARATHION (6 total), please visit the HSDB record page.