AZADUAL 100

Indications

• Cerebral edema
• Elevated intracranial pressure
• Acute kidney injury
• Oliguria
• Glaucoma
• Renal function diagnostic aid

Dosage

Adults: For cerebral edema, administer 0

Mechanism of action

Mannitol elevates blood plasma osmolality, resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma. This action reduces cerebral edema and intracranial pressure. As a diuretic, it increases the osmolality of glomerular filtrate, leading to increased urinary excretion of water and preventing sodium and chloride reabsorption in the renal tubules. Mannitol also facilitates the urinary excretion of toxic substances and can help in assessing renal function by measuring glomerular filtration rate (GFR).

Pharmacodynamics

Mannitol is classified as an osmotic diuretic. It is chemically similar to other sugar alcohols but has a unique ability to promote diuresis by remaining unabsorbed in the renal tubules. Its use is indicated for conditions associated with increased body fluids, such as cerebral edema and glaucoma. Mannitol may be combined with other diuretics to enhance diuretic efficacy. Inhaled formulations are used in cystic fibrosis, though they may cause bronchospasm and hemoptysis.

Pharmacokinetics

Mannitol is freely filtered by the glomeruli with less than 10% tubular reabsorption, which allows for its urinary excretion rate to serve as a measurement of GFR. It does not undergo significant metabolism and is eliminated primarily through the kidneys. The onset of action occurs within 30 to 60 minutes after intravenous administration, with effects lasting for several hours. Administration may require monitoring of renal function and fluid balance.

Contra-indications

• Anuria
• Severe dehydration
• Severe renal impairment
• Intracranial bleeding

Adverse effects

• Asthenia
• Gastrointestinal disturbances
• Dry mouth
• Confusion
• Visual impairment
• Hypotension
• Electrolyte imbalances
• Pulmonary edema
• Hemoptysis (with inhalation use)
• Bronchospasm (with inhalation use)

Interactions

• Potassium-sparing diuretics may increase the risk of hyperkalemia
• Other diuretics may have additive effects
• Caution with nephrotoxic agents

Precautions

• Caution in patients with diabetes mellitus
• Caution in the elderly
• Caution in patients with gout
• Caution in patients with hepatic impairment
• Monitor renal function and electrolytes regularly
• May cause blue fluorescence of urine

Pregnancy

Manufacturer advises avoid due to potential toxicity in animal studies.

Breast-feeding

Manufacturer advises avoid due to lack of information available.

Storage

Store in a cool, dry place, away from light. Do not freeze.

Formulations

• Solution for injection
• Inhalation powder
• Oral solution

Indications

• Myelodysplastic syndromes (MDS)
• Acute myeloid leukemia (AML)
• Chronic myelomonocytic leukemia (CMML)

Dosage

Adults: The recommended dosage of azacitidine for adults

Mechanism of action

Azacitidine induces its antineoplastic activity by inhibiting DNA methyltransferase at low doses, which leads to DNA hypomethylation and prevents DNA synthesis. At high doses, it incorporates into RNA and DNA, disrupting RNA metabolism and protein synthesis. After cellular uptake, it is phosphorylated to form 5-azacytidine monophosphate, which is further phosphorylated to diphosphate and triphosphate forms. Azacitidine triphosphate incorporates into RNA, while 5-aza-deoxycytidine triphosphate incorporates into DNA, inhibiting DNA synthesis and leading to cell death, particularly during the S-phase of the cell cycle.

Pharmacodynamics

Azacitidine demonstrates a unique pharmacodynamic profile where it can inhibit DNA methylation without significantly suppressing DNA synthesis initially. This hypomethylation can restore normal gene function critical for cell differentiation and proliferation. Clinical use has shown that azacitidine treatment leads to reduced genome-wide DNA methylation levels in bone marrow cells, corroborating its mechanism of action. However, it is associated with side effects such as anemia, neutropenia, and thrombocytopenia, and may pose risks of renal toxicity and hepatotoxicity in susceptible individuals.

Pharmacokinetics

After administration, azacitidine is rapidly absorbed and undergoes extensive metabolism. It is phosphorylated in cells to active forms, which are involved in its incorporation into nucleic acids. The drug has a variable half-life and is primarily eliminated through renal pathways. The pharmacokinetic profile indicates that azacitidine reaches peak concentrations shortly after administration, with effects noted predominantly during the S-phase of the cell cycle.

Contra-indications

• Active severe infection
• Unstable cardiac disease
• History of cardiovascular disease
• Previous therapy with anthracyclines or anthracenediones
• Previous radiotherapy to the mediastinal area

Adverse effects

• Anemia
• Neutropenia
• Thrombocytopenia
• Nausea
• Vomiting
• Diarrhea
• Constipation
• Fatigue
• Chills
• Dizziness
• Mucositis
• Pulmonary toxicity
• Skin reactions
• Altered taste
• Oliguria
• Chest pain
• Confusion
• Dry eye
• Eosinophilia
• Hyperbilirubinemia
• Hyperuricemia
• Alopecia
• Arthralgia
• Asthenia
• Local reactions at the injection site
• Night sweats

Interactions

• Concurrent use with other cytotoxic agents may increase the risk of hematologic toxicity.
• Caution is advised when combined with drugs that affect liver enzymes.

Precautions

• Monitor full blood count and cardiac function throughout treatment.
• Consider secondary assessment before and during treatment in patients with unstable malignancy or pulmonary disease.
• Handle with care as it is an irritant to tissues.

Pregnancy

Azacitidine may cause embryo-fetal toxicity and is not recommended during pregnancy.

Breast-feeding

The effects on breastfed infants are unknown; caution is advised.

Storage

Store in a refrigerator (2 to 8 degrees Celsius). Protect from light. Do not freeze.

Formulations

• Powder for solution for infusion
• Solution for infusion

Dosage

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

Adults: Refer to the BNF for specific dosing guidance.

Mechanism of action

Aliphatic nitriles, including acetonitrile, are metabolically activated by hepatic mechanisms to release cyanide, which is responsible for the major acute toxic effects associated with this compound.

Pharmacodynamics

The pharmacodynamics of acetonitrile are largely related to its metabolic conversion to cyanide in the liver. Cyanide inhibits cellular respiration by binding to cytochrome c oxidase in the mitochondrial electron transport chain, leading to cellular hypoxia and metabolic acidosis. Symptoms of toxicity can include headache, dizziness, nausea, and in severe cases, respiratory failure or death.

Pharmacokinetics

Acetonitrile is rapidly absorbed following ingestion or inhalation. It is metabolized in the liver where it undergoes conversion to cyanide. The half-life of acetonitrile in the body is relatively short, and elimination occurs primarily through renal excretion of metabolites. The activation to cyanide is dose-dependent and can vary based on the individual's hepatic function.

Pregnancy

There are no adequate and well-controlled studies in pregnant women. The potential risks should be weighed against the benefits when considering use during pregnancy.

Breast-feeding

It is not known whether acetonitrile is excreted in human milk. Caution should be exercised when administering to breastfeeding women.

Storage

Store in a tightly closed container in a cool, dry, well-ventilated area away from incompatible substances.

Indications

• Pain management
• Vaccination
• Antibiotic therapy
• Hormonal therapies
• Anesthesia
• Nutritional support
• Chemotherapy

Dosage

Children: Refer to specific drug guidelines for paediatric dosing, as it requires careful consideration of weight and age.

Adults: Refer to specific drug guidelines for adult dosing, as it varies widely depending on the medication and clinical condition.

Mechanism of action

The mechanism of action of injected drugs varies widely based on the specific medication being administered. Generally, injected drugs enter the bloodstream directly, allowing them to circulate rapidly throughout the body. For instance, antibiotics may work by inhibiting bacterial cell wall synthesis, while analgesics may modulate pain pathways in the central nervous system. Each drug has unique pathways through which it achieves its therapeutic effects.

Pharmacodynamics

Pharmacodynamics refers to the effects of drugs on the body and their mechanisms of action. For injectable medications, effects can be immediate or delayed, depending on the drug's formulation and route of administration. Factors influencing pharmacodynamics include receptor affinity, drug concentration, and the presence of other substances that may enhance or inhibit the drug's effects. For example, some injectable drugs may require specific receptors to exert their effects, while others may have a broader range of action.

Pharmacokinetics

Pharmacokinetics involves the absorption, distribution, metabolism, and excretion (ADME) of injected drugs. After administration, drugs are rapidly absorbed into the bloodstream, leading to quick therapeutic effects. The distribution depends on factors such as blood flow, tissue permeability, and protein binding. Drugs are metabolized primarily in the liver and excreted through the kidneys or bile. The pharmacokinetic profile can vary widely based on the drug's chemical nature, dosage, and individual patient factors.

Pregnancy

Safety during pregnancy depends on the specific injection and its active ingredients. It is essential to consult a healthcare professional for guidance.

Breast-feeding

The safety of injections during breastfeeding varies by the specific medication. It is recommended to seek advice from a healthcare provider.

Storage

Store injections as per manufacturer's guidelines, usually in a cool, dry place away from direct sunlight. Some may require refrigeration.

Mechanism of action

Azacitidine (5-azacytidine) is a chemical analogue of the cytosine nucleoside present in DNA and RNA. It induces antineoplastic activity by inhibiting DNA methyltransferase at low doses and inducing cytotoxicity by incorporating itself into RNA and DNA at high doses. Covalent binding to DNA methyltransferase results in DNA hypomethylation and prevents DNA synthesis. On the other hand, the incorporation of azacitidine into RNA and DNA leads to cytotoxicity as follows: Following cellular uptake, azacitidine is phosphorylated by uridine-cytidine kinase to form 5-azacytidine monophosphate. Afterwards, pyrimidine monophosphate and diphosphate kinases phosphorylate 5-azacytidine monophosphate to form 5-azacytidine diphosphate and triphosphate, respectively. Azacitidine triphosphate is able to incorporate into RNA, disrupting RNA metabolism and protein synthesis. The reduction of azacytidine diphosphate leads to the formation of 5-aza-deoxycytidine diphosphate, which is then phosphorylated to form 5-azadeoxycitidine triphosphate, a compound able to incorporate into DNA and inhibit DNA synthesis. As a ribonucleoside, azacitidine incorporates into RNA to a larger extent than into DNA. Incorporating into RNA leads to the disassembly of polyribosomes, defective methylation and acceptor function of transfer RNA, and the inhibition of protein production, resulting in cell death. During the S-phase of the cell cycle, azacitidine exhibits the highest toxicity; however, the predominant mechanism of cytotoxicity has not been elucidated. The cytotoxic effects of azacitidine cause the death of rapidly dividing cells, including cancer cells that are no longer responsive to normal growth control mechanisms. Non-proliferating cells are relatively insensitive to azacitidine. It is believed that azacitidine exerts its antineoplastic effects through direct cytotoxicity on abnormal hematopoietic cells in the bone marrow. Telomerase activation is thought to be a critical step in cellular immortality and oncogenesis. Several reagents including differentiation-inducing and antineoplastic agents are known to inhibit telomerase activity, although the molecular mechanisms through which they inhibit telomerase activity remain unclear. Demethylating reagents have recently been used as potential antineoplastic drugs for some types of cancers including those of the prostate. In the present study, we examined the effect of the demethylating reagent 5-azacytidine (5-aza-CR) on telomerase activity using cells of two prostate cancer cell lines, DU-145 and TSU-PR1. 5-aza-CR treatment significantly reduced telomerase activity in TSU-PR1 cells, but not in DU-145 cells, although growth inhibition was observed to a similar extent in both cell lines. Reverse transcription-PCR analyses revealed that inhibition of telomerase activity was accompanied by down-regulation of telomerase catalytic subunit (hTERT) mRNA expression. Transient expression assays showed that 5-aza-CR repressed the transcriptional activity of the hTERT promoter and that the E-box within the core promoter was responsible for this down-regulation. Western blot analyses revealed that 5-aza-CR reactivated p16 expression and repressed c-Myc expression in TSU-PR1 cells but not in DU-145 cells. Overexpression of p16 in TSU-PR1 cells led to significant repression of c-Myc transcription. These findings suggest that 5-aza-CR inhibits telomerase activity via transcriptional repression of hTERT, in which p16 and c-Myc may play a key role. Cellular differentiation is controlled by a variety of factors including gene methylation, which represses particular genes as cell fate is determined. The incorporation of 5-azacytidine (5azaC) into DNA in vitro prevents methylation and thus can alter cellular differentiation pathways. Human bone marrow fibroblasts and MG63 cells treated with 5azaC were used as models of osteogenic progenitors and of a more mature osteoblast phenotype, respectively. The capacity for different

Pharmacodynamics

The concentration of azacitidine required for maximum inhibition of DNA methylation in vitro does not cause major suppression of DNA synthesis, and hypomethylation may restore normal function to genes critical for differentiation and proliferation. Genome-wide DNA methylation levels in bone marrow granulocytes were reduced in patients with juvenile myelomonocytic leukemia after the first treatment cycle of azacitidine (75 mg/m² or 2.5 mg/kg), confirming the DNA-hypomethylating activity of azacitidine. The use of azacitidine causes anemia, neutropenia and thrombocytopenia in adult patients with myelodysplastic syndrome and pediatric patients with juvenile myelomonocytic leukemia. Azacitidine may cause renal toxicity, tumor lysis syndrome and embryo-fetal toxicity. It may also lead to the development of hepatotoxicity in patients with severe pre-existing hepatic impairment.

Mechanism of action

Mannitol is an osmotic diuretic that is metabolically inert in humans and occurs naturally, as a sugar or sugar alcohol, in fruits and vegetables. Mannitol elevates blood plasma osmolality, resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma. As a result, cerebral edema, elevated intracranial pressure, and cerebrospinal fluid volume and pressure may be reduced. As a diurectic mannitol induces diuresis because it is not reabsorbed in the renal tubule, thereby increasing the osmolality of the glomerular filtrate, facilitating excretion of water, and inhibiting the renal tubular reabsorption of sodium, chloride, and other solutes. Mannitol promotes the urinary excretion of toxic materials and protects against nephrotoxicity by preventing the concentration of toxic substances in the tubular fluid. As an Antiglaucoma agent mannitol levates blood plasma osmolarity, resulting in enhanced flow of water from the eye into plasma and a consequent reduction in intraocular pressure. As a renal function diagnostic aid mannitol is freely filtered by the glomeruli with less than 10% tubular reabsorption. Therefore, its urinary excretion rate may serve as a measurement of glomerular filtration rate (GFR). The exact mechanism of action of inhaled mannitol in the symptomatic maintenance treatment of cystic fibrosis remains unclear. It is hypothesized that mannitol produces an osmotic gradient across the airway epithelium that draws fluid into the extracellular space and alters the properties of the airway surface mucus layer, allowing easier mucociliary clearance. MANNITOL IS.../USED/ IN PROPHYLAXIS OF ACUTE RENAL FAILURE. IT IS USED FOR THIS PURPOSE IN CONDITIONS AS DIVERSE AS CARDIOVASCULAR OPERATIONS, SEVERE TRAUMATIC INJURY, OPERATIONS IN THE PRESENCE OF SEVERE JAUNDICE, AND MGMNT OF HEMOLYTIC TRANSFUSION REACTIONS. IN EACH OF THESE CONDITIONS, A PRECIPITOUS FALL IN THE FLOW OF URINE MAY BE ANTICIPATED EITHER AS THE RESULT OF AN ACUTELY REDUCED FILTRATION RATE OR FROM ACUTE CHANGES IN TUBULAR PERMEABILITY. THE LATTER MAY BE CONSEQUENCE OF THE PRESENCE OF NOXIOUS AGENT WITHIN THE TUBULAR FLUID IN EXCESSIVELY HIGH CONCN, IN SOME INSTANCES SUFFICIENT TO RESULT IN ACTUAL PRECIPITATION. IN THESE SITUATIONS, MANNITOL EXERTS OSMOTIC EFFECT WITHIN THE TUBULAR FLUID, INHIBITS WATER REABSORPTION, & MAINTAINS THE RATE OF URINE FLOW. ...CONCN OF TOXIC AGENT WITHIN TUBULAR FLUID DOES NOT REACH EXCESSIVELY HIGH LEVELS THAT OTHERWISE WOULD HAVE BEEN ACHIEVED BY MORE COMPLETE REABSORPTION OF WATER. ...EVEN THOUGH /GLOMERULAR/ FILTRATION RATE IS REDUCED, MANNITOL IS STILL FILTERED @ GLOMERULUS. THE TUBULAR IMPERMEABILITY TO MANNITOL IS NOT ALTERED BY ACUTE RENAL ISCHEMIA OF SHORT DURATION. HENCE, THE MANNITOL THAT IS FILTERED IS ALSO EXCRETED IN THE VOIDED URINE. UNREABSORBED SOLUTE LIMITS BACK DIFFUSION OF WATER. ...URINE VOL CAN BE MAINTAINED EVEN IN PRESENCE OF DECR GLOMERULAR FILTRATION.

Pharmacodynamics

Chemically, mannitol is an alcohol and a sugar, or a polyol; it is similar to xylitol or sorbitol. However, mannitol has a tendency to lose a hydrogen ion in aqueous solutions, which causes the solution to become acidic. For this reason, it is not uncommon to add a substance to adjust its pH, such as sodium bicarbonate. Mannitol is commonly used to increase urine production (diuretic). It is also used to treat or prevent medical conditions that are caused by an increase in body fluids/water (e.g., cerebral edema, glaucoma, kidney failure). Mannitol is frequently given along with other diuretics (e.g., furosemide, chlorothiazide) and/or IV fluid replacement. Inhaled mannitol has the possibility to cause bronchospasm and hemoptysis; the occurrence of either should lead to discontinuation of inhaled mannitol.

Mechanism of action

Aliphatic nitriles (including acetonitrile) possess little if any acute toxicity in absence of normal hepatic function & are activated by hepatic mechanisms to release cyanide which accounts for major acute toxic effects.