TYLO P.C GOLD

Indications

• Corticosteroid-responsive conditions
• Autoimmune diseases
• Inflammatory eye conditions
• Certain malignancies
• Chronic inflammatory disorders

Dosage

Children: Refer to the BNF for Children for appropriate paediatric dosing recommendations based on age and weight.

Adults: Refer to the BNF for specific adult dosing guidelines based on the condition being treated. Doses may vary depending on the severity of the condition and the clinical response.

Mechanism of action

Prednisolone binds to the glucocorticoid receptor, resulting in altered gene expression that decreases vasodilation, capillary permeability, and leukocyte migration to sites of inflammation. It inhibits phospholipase A2, reducing the production of arachidonic acid derivatives, and suppresses pro-inflammatory transcription factors such as NF-Kappa B. This results in an anti-inflammatory effect at lower doses and immunosuppressive effects at higher doses.

Pharmacodynamics

Corticosteroids like prednisolone exert their effects by inhibiting pro-inflammatory signals and promoting anti-inflammatory signals through their action on the glucocorticoid receptor. Prednisolone has a relatively short half-life of 2.1 to 3.5 hours, and while it has a wide therapeutic window, long-term use can lead to hypothalamic-pituitary-adrenal axis suppression and increased infection risk.

Pharmacokinetics

Prednisolone is rapidly absorbed and has a short duration of action. Its pharmacokinetics involve extensive metabolism in the liver, primarily through hepatic enzymes, leading to various metabolites. The elimination half-life is approximately 2.1 to 3.5 hours, and it is primarily excreted in the urine. Chronic use can affect circadian rhythms and homeostasis.

Contra-indications

• Known allergy to prednisolone or any of its components
• Systemic fungal infections
• Active tuberculosis
• Untreated bacterial infections

Adverse effects

• Increased susceptibility to infections
• Gastrointestinal disturbances
• Fluid retention
• Hypertension
• Cushing's syndrome
• Osteoporosis
• Mood changes
• Hyperglycemia

Interactions

• Mitotane (Moderate - decreases exposure)
• Rifampicin (Moderate - decreases exposure)
• Cobicistat (Unknown - increases exposure)
• Idelalisib (Unknown - increases exposure)
• Clarithromycin (Unknown - increases exposure)

Precautions

• Monitor for signs of infection during therapy
• Use with caution in patients with a history of gastrointestinal ulcers
• Tapering of dosage may be necessary to avoid withdrawal symptoms
• Consider potential effects on growth in pediatric patients

Pregnancy

Prednisolone is classified as a Category C drug. It should only be used if the potential benefits justify the potential risk to the fetus.

Breast-feeding

Prednisolone is excreted in breast milk. Caution should be exercised when administered to nursing mothers.

Storage

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

Formulations

• Tablets: 2 mg, 4 mg, 16 mg, 100 mg
• Suspension for injection
• Powder and solvent for solution for injection

Indications

• Bacterial infections
• Respiratory tract infections
• Urinary tract infections
• Skin and soft tissue infections
• Infections caused by resistant bacteria

Dosage

Children: Refer to the BNF for Children for appropriate dosing in paediatric patients.

Adults: Refer to the BNF for specific dosing information as it varies based on the type and severity of the infection.

Mechanism of action

Thiamphenicol works by inhibiting bacterial protein synthesis. It binds to the 50S subunit of the bacterial ribosome, preventing the peptidyl transferase activity which is essential for the formation of peptide bonds. This action effectively halts the growth and reproduction of bacteria.

Pharmacodynamics

The pharmacodynamics of thiamphenicol is characterized by its bacteriostatic activity against a wide range of bacteria. Its efficacy is influenced by factors such as the concentration of the drug at the site of infection and the susceptibility of the bacteria. Resistance to thiamphenicol can occur through the production of acetyltransferases that inactivate the drug or through mutations in the ribosomal target site.

Pharmacokinetics

Thiamphenicol is well absorbed following oral administration. It is widely distributed throughout body tissues and fluids, achieving high concentrations in the lungs and central nervous system. The drug undergoes hepatic metabolism, primarily through conjugation, and is excreted mainly in the urine as metabolites. The elimination half-life is approximately 3 to 5 hours, and dosing adjustments may be needed in patients with renal impairment.

Contra-indications

• Hypersensitivity to thiamphenicol or any component of the formulation
• History of blood dyscrasias associated with chloramphenicol or thiamphenicol

Adverse effects

• Nausea
• Vomiting
• Diarrhoea
• Aplastic anaemia
• Thrombocytopenia
• Leukopenia

Interactions

• Increased risk of bone marrow suppression when used with other drugs that can affect bone marrow
• May reduce the efficacy of live vaccines

Precautions

• Monitor for signs of blood dyscrasias
• Use with caution in patients with liver impairment
• Caution in patients with a history of renal disease

Pregnancy

Thiamphenicol should only be used during pregnancy if the benefits outweigh the risks, as it may cross the placenta.

Breast-feeding

Thiamphenicol is excreted in breast milk; caution is advised when administering to nursing mothers.

Storage

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

Formulations

• Thiamphenicol capsules
• Thiamphenicol oral suspension
• Thiamphenicol injection

Indications

• Bacterial infections in livestock
• Respiratory infections
• Enteritis caused by various pathogens
• Mycoplasma infections

Dosage

Children: For paediatric dosing, refer to the BNF for Children for appropriate dosing information based on age and weight.

Adults: Refer to the BNF for specific dosing guidelines based on the condition being treated, as doses may vary.

Mechanism of action

Tylosin inhibits peptide bond formation by binding to the 50S ribosomal subunit of bacteria, blocking the aminoacyl-tRNA from entering the ribosome and thus halting protein synthesis. This inhibition acts as a slow-binding, slowly reversible process, and the interaction with the ribosome is characterized by a significant degree of irreversibility, which is crucial for its antibiotic properties.

Pharmacodynamics

Tylosin exhibits bacteriostatic activity, meaning it inhibits bacterial growth rather than directly killing bacteria. Its effectiveness is particularly notable against certain strains of bacteria that are resistant to other antibiotic classes. The irreversibility of its action on the ribosome contributes to its long-lasting effects against bacterial infections.

Pharmacokinetics

After administration, tylosin is absorbed and distributed throughout the body. It is metabolized in the liver and excreted primarily in the bile, with some renal excretion. The half-life of tylosin can vary based on the route of administration and the species being treated. It is important to monitor for potential accumulation in cases of renal impairment.

Pregnancy

There is insufficient data on the use of tylosin during pregnancy. It should only be used if the potential benefits outweigh the risks.

Breast-feeding

It is not known whether tylosin is excreted in human milk. Caution should be exercised when administering to nursing mothers.

Storage

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

Formulations

• Tylosin tartrate tablets
• Tylosin injectable solution
• Tylosin oral suspension

Mechanism of action

The short term effects of corticosteroids are decreased vasodilation and permeability of capillaries, as well as decreased leukocyte migration to sites of inflammation. Corticosteroids binding to the glucocorticoid receptor mediates changes in gene expression that lead to multiple downstream effects over hours to days. Glucocorticoids inhibit neutrophil apoptosis and demargination; they inhibit phospholipase A2, which decreases the formation of arachidonic acid derivatives; they inhibit NF-Kappa B and other inflammatory transcription factors; they promote anti-inflammatory genes like interleukin-10. Lower doses of corticosteroids provide an anti-inflammatory effect, while higher doses are immunosuppressive. High doses of glucocorticoids for an extended period bind to the mineralocorticoid receptor, raising sodium levels and decreasing potassium levels. Although altered homeostatic regulation, including disturbance of 24-h rhythms, is often observed in the patients undergoing glucocorticoid therapy, the mechanisms underlying the disturbance remains poorly understood. We report here that chronic treatment with a synthetic glucocorticoid, prednisolone, can cause alteration of circadian clock function at molecular level. Treatment of cultured hepatic cells (HepG2) with prednisolone induced expression of Period1 (Per1), and the prednisolone treatment also attenuated the serum-induced oscillations in the expression of Period2 (Per2), Rev-erbalpha, and Bmal1 mRNA in HepG2 cells. Because the attenuation of clock gene oscillations was blocked by pretreating the cells with a Per1 antisense phosphothioate oligodeoxynucleotide, the extensive expression of Per1 induced by prednisolone may have resulted in the reduced amplitude of other clock gene oscillations. Continuous administration of prednisolone into mice constitutively increased the Per1 mRNA levels in liver and skeletal muscle, which seems to attenuate the oscillation in the expressions of Per2, Rev-erbalpha, and Bmal1. However, a single daily administration of prednisolone at the time of day corresponding to acrophase of endogenous glucocorticoid levels had little effect on the rhythmic expression of clock genes. These results suggest a possible pharmacological action by prednisolone on the core circadian oscillation mechanism and indicate the possibility that the alteration of clock function induced by prednisolone can be avoided by optimizing the dosing schedule. Glucocorticoids are capable of suppressing the inflammatory process through numerous pathways. They interact with specific intracellular receptor proteins in target tissues to alter the expression of corticosteroid-responsive genes. Glucocorticoid-specific receptors in the cell cytoplasm bind with steroid ligands to form hormone-receptor complexes that eventually translocate to the cell nucleus. There these complexes bind to specific DNA sequences and alter their expression. The complexes may induce the transcription of mRNA leading to synthesis of new proteins. Such proteins include lipocortin, a protein known to inhibit PLA2a and thereby block the synthesis of prostaglandins, leukotrienes, and PAF. Glucocorticoids also inhibit the production of other mediators including AA metabolites such as COX, cytokines, the interleukins, adhesion molecules, and enzymes such as collagenase. /Glucocorticoids/

Pharmacodynamics

Corticosteroids bind to the glucocorticoid receptor, inhibiting pro-inflammatory signals, and promoting anti-inflammatory signals. Prednisolone has a short duration of action as the half life is 2.1-3.5 hours. Corticosteroids have a wide therapeutic window as patients make require doses that are multiples of what the body naturally produces. Patients taking corticosteroids should be counselled regarding the risk of hypothalamic-pituitary-adrenal axis suppression and increased susceptibility to infections.

Mechanism of action

The inhibition of peptide bond formation by tylosin, a 16-membered ring macrolide, was studied in a model system derived from Escherichia coli. In this cell-free system, a peptide bond is formed between puromycin (acceptor substrate) and AcPhe-tRNA (donor substrate) bound at the P-site of poly(U)-programmed ribosomes. It is shown that tylosin inhibits puromycin reaction as a slow-binding, slowly reversible inhibitor. Detailed kinetic analysis reveals that tylosin (I) reacts rapidly with complex C, i.e., the AcPhe-tRNA. poly(U).70S ribosome complex, to form the encounter complex CI, which then undergoes a slow isomerization and is converted to a tight complex, CI, inactive toward puromycin. These events are described by the scheme C + I <==> (K(i)) CI <==> (k(4), k(5)) CI. The K(i), k(4), and k(5) values are equal to 3 microM, 1.5 min(-1), and 2.5 x 10(-3) min(-1), respectively. The extremely low value of k(5) implies that the inactivation of complex C by tylosin is almost irreversible. The irreversibility of the tylosin effect on peptide bond formation is significant for the interpretation of this antibiotic's therapeutic properties; it also renders the tylosin reaction a useful tool in the study of other macrolides failing to inhibit the puromycin reaction but competing with tylosin for common binding sites on the ribosome. Thus, the tylosin reaction, in conjunction with the puromycin reaction, was applied to investigate the erythromycin mode of action. It is shown that erythromycin (Er), like tylosin, interacts with complex C according to the kinetic scheme C + Er <==> (K(er)) CEr <==> (k(6), k(7)) C*Er and forms a tight complex, CEr, which remains active toward puromycin. The determination of K(er), k(6), and k(7) enables us to classify erythromycin as a slow-binding ligand of ribosomes