GEMTOR 200 for IV Injection

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

Mechanism of action

Gemcitabine is phosphorylated by deoxycytidine kinase in malignant cells to form gemcitabine monophosphate, which is then converted into gemcitabine diphosphate (dFdCDP) and gemcitabine triphosphate (dFdCTP). These metabolites competitively inhibit DNA chain elongation by incorporating into DNA in place of deoxycytidine triphosphate (dCTP), leading to masked DNA chain termination. This results in DNA fragmentation and apoptotic cell death. Additionally, dFdCDP inhibits ribonucleotide reductase, reducing dCTP levels and enhancing the incorporation of dFdCTP into DNA. This self-potentiating action prolongs the intracellular concentration of active metabolites.

Pharmacodynamics

Gemcitabine promotes apoptosis in malignant cells during DNA synthesis, effectively blocking the G1/S-phase boundary of the cell cycle. It exhibits cytotoxic effects against a broad range of cancer cell lines in vitro and demonstrates schedule-dependent antitumor activity in various animal models. Clinical trials indicate that gemcitabine monotherapy produces objective response rates of 18-26% in advanced non-small cell lung cancer, with median survival times ranging from 6.2 to 12.3 months. The drug is more effective when administered as a prolonged infusion rather than at higher dosages.

Pharmacokinetics

Gemcitabine is administered intravenously, and its pharmacokinetics can vary based on the specific malignancy being treated and the combination with other agents. The drug is rapidly distributed in the body and metabolized primarily by deoxycytidine kinase into its active forms. Its elimination half-life is short, and active metabolites are cleared from the body relatively quickly. Caution is advised in patients with hepatic or renal impairment, and adjustment of dosage may be necessary.

Contra-indications

• Hypersensitivity to gemcitabine or any component of the formulation
• Pregnancy
• Severe hepatic impairment

Adverse effects

• Alopecia
• Anemia
• Nausea
• Vomiting
• Infection risk increase
• Fatigue
• Thrombocytopenia
• Neutropenia
• Diarrhea
• Stomatitis

Interactions

• Live vaccines may increase the risk of generalized infection, possibly life-threatening

Precautions

• Caution in handling due to irritant properties
• Monitor for signs of infection due to immunosuppression
• Adjust dosage in patients with renal or hepatic impairment
• Use with caution in elderly patients

Pregnancy

Avoid, teratogenic in animal studies.

Breast-feeding

Discontinue breastfeeding during treatment.

Storage

Store in a cool, dry place, protected from light. Refer to specific product labeling for storage conditions.

Formulations

• 100 mg/5 ml solution for injection
• 500 mg/20 ml solution for injection
• 1 g/20 ml solution for injection
• 2 g/200 ml infusion bags
• 5 g/100 ml solution for infusion vials

Dosage

Children: Refer to specific drug guidelines for paediatric dosing, as this varies widely.

Adults: Refer to specific drug guidelines for adult dosing, as this varies widely.

Mechanism of action

The mechanism of action will vary depending on the specific drug referred to as 'adjust'. Generally, medications designed to 'adjust' physiological parameters may work by modulating neurotransmitter systems, altering hormonal levels, or affecting enzyme activity to achieve therapeutic effects.

Pharmacodynamics

Pharmacodynamics will depend on the specific drug, but typically involves the interaction of the drug with its receptor sites, leading to a biological response. The efficacy and potency of the drug are influenced by its affinity for the target receptors and the subsequent signaling pathways activated.

Pharmacokinetics

Pharmacokinetics, including absorption, distribution, metabolism, and excretion, will vary by drug. Common factors influencing pharmacokinetics include bioavailability, half-life, and the presence of food or other drugs that may affect the drug's metabolism and elimination from the body.

Indications

• Adjustment of pH in pharmaceutical formulations
• Facilitation of drug absorption
• Used in sterile preparations

Dosage

Children: Refer to specific product guidelines for dosing information, as hydrochloric acid is typically used in a controlled setting based on formulation requirements.

Adults: Refer to specific product guidelines for dosing information, as hydrochloric acid is typically used in a controlled setting based on formulation requirements.

Mechanism of action

Hydrochloric acid dissociates in aqueous solution to release hydrogen ions (H+), leading to a decrease in pH. This acidic environment promotes the activation of pepsinogen to pepsin, an enzyme essential for protein digestion. Additionally, the acidity aids in the absorption of certain minerals and drugs that require an acidic environment for optimal bioavailability.

Pharmacodynamics

The primary pharmacodynamic action of hydrochloric acid is the maintenance of gastric acidity, which is essential for normal digestive processes. The acidic environment helps in denaturing proteins, activating digestive enzymes, and providing a barrier against pathogenic microorganisms. Its effects can influence the absorption and efficacy of various medications, particularly those that are pH-dependent.

Pharmacokinetics

Hydrochloric acid does not undergo significant systemic absorption when used in its normal contexts, as it acts locally within the gastrointestinal tract. The amount of hydrochloric acid produced by the stomach varies with food intake and physiological needs. It is secreted by parietal cells in the gastric mucosa, and its secretion is regulated by neural, hormonal, and local factors. The half-life of hydrochloric acid is not applicable as it is continuously produced and neutralized within the gastrointestinal tract.

Contra-indications

• Hypersensitivity to hydrochloric acid or any of its components
• Severe renal impairment
• Active gastrointestinal bleeding

Adverse effects

• Abdominal pain
• Diarrhea
• Nausea
• Vomiting
• Esophageal irritation
• Gastric mucosal irritation
• Electrolyte imbalances

Interactions

• May interact with alkaline substances, potentially neutralizing hydrochloric acid
• Caution with antacids as they may affect the efficacy of hydrochloric acid

Precautions

• Use with caution in patients with a history of gastritis or gastric ulcers
• Monitor electrolytes in prolonged use
• Use cautiously in patients with respiratory conditions due to potential aspiration risks

Pregnancy

Hydrochloric acid is classified as a category C drug. Use during pregnancy only if clearly needed and the potential benefits justify the risks to the fetus.

Breast-feeding

There is limited data on the excretion of hydrochloric acid in human milk. Use with caution during breastfeeding.

Storage

Store in a cool, dry place away from direct sunlight and heat. Ensure the container is tightly closed.

Formulations

• Oral solutions
• Injectable forms
• Tablets

Dosage

Children: Refer to specific guidelines for pediatric dosing; consult the BNF for Children for accurate dosage information.

Adults: Refer to specific guidelines for use; dosage may vary based on the context of use.

Mechanism of action

Hydroxide ions act primarily as bases, neutralizing acids to form water and salts. They participate in various biochemical pathways, including selenium metabolism and the degradation of reactive oxygen species. Hydroxide can influence enzyme activity and stability by altering the pH of the environment, thereby affecting metabolic reactions.

Pharmacodynamics

Hydroxide ions can impact biological processes by changing the local pH, which influences enzyme activity, ion transport, and the solubility of other compounds. Their ability to neutralize acids can help regulate physiological pH, contributing to homeostasis in living organisms.

Pharmacokinetics

As an inorganic ion, hydroxide does not undergo traditional pharmacokinetic processes like absorption, distribution, metabolism, or excretion. Instead, it is rapidly equilibrated in biological fluids and participates in acid-base reactions, having immediate effects on the local environment.

Pregnancy

There is limited information regarding the use of hydroxide during pregnancy. Consult a healthcare professional for advice.

Breast-feeding

Limited data is available on the excretion of hydroxide in breast milk. Consult a healthcare professional before use.

Storage

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

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

Gemcitabine is a potent and specific deoxycytidine analog. After uptake into malignant cells, gemcitabine is phosphorylated by deoxycytidine kinase to form gemcitabine monophosphate, which is then converted to the active compounds, gemcitabine diphosphate (dFdCDP) and gemcitabine triphosphate (dFdCTP). These active metabolites are nucleosides that mediate antitumour effects. dFdCTP competes with deoxycytidine triphosphate (dCTP) for incorporation into DNA, thereby competitively inhibiting DNA chain elongation. The non-terminal position of dFdCTP in the DNA chain prevents detection of dFdCTP in the chain and repair by proof-reading 3′5′-exonuclease: this process is referred to as "masked DNA chain termination." Incorporation of dFdCTP into the DNA chain ultimately leads to chain termination, DNA fragmentation, and apoptotic cell death of malignant cells. Gemcitabine has self-potentiating pharmacological actions that can increase the probability of successful incorporation of gemcitabine triphosphate into the DNA chain: dFdCDP inhibits ribonucleotide reductase, an enzyme responsible for catalyzing the reactions that generate dCTP for DNA synthesis. Since dFdCDP reduces the levels of dCTP, there is less competition for gemcitabine triphosphate for incorporation into DNA. Gemcitabine can also reduce metabolism and elimination of active metabolites from the target ce1l, prolonging high intracellular concentrations of the active metabolites. Such self-potentiating effects are not present with [cytarabine]. Gemcitabine hydrochloride, a synthetic pyrimidine nucleoside, is an antineoplastic agent. The nucleoside analog consists of the pyrimidine base difluorocytidine, and the sugar moiety deoxyribose. Like most antimetabolite antineoplastic agents, gemcitabine is cell-cycle specific, acting principally in the S phase of the cell cycle; the drug also may cause cellular arrest at the G1-S border. The cytotoxic activity of gemcitabine (2'-deoxy-2',2'-difluorocytidine) depends on intracellular conversion to its 5'-diphosphate and -triphosphate metabolites; thus, deoxydifluorocytidine-5?-diphosphate (dFdCDP, gemcitabine diphosphate) and -triphosphate (dFdCTP, gemcitabine triphosphate) and not unchanged gemcitabine are the pharmacologically active forms of the drug. Gemcitabine is phosphorylated by deoxycytidine kinase to gemcitabine monophosphate, which subsequently is phosphorylated to the corresponding diphosphate and triphosphate nucleosides, presumably by deoxycytidylate kinase and nucleoside diphosphate kinase, respectively. The cytotoxic effect of gemcitabine is attributed to the combined actions of its diphosphate and triphosphate nucleosides, which lead to inhibition of DNA synthesis. Gemcitabine diphosphate inhibits ribonucleotide reductase, which is responsible for catalyzing the formation of deoxynucleoside triphosphates needed in DNA synthesis. By inhibiting this reductase, gemcitabine diphosphate interferes with subsequent de novo nucleotide production. Gemcitabine triphosphate inhibits DNA synthesis by competing with the physiologic substrate, deoxycytidine triphosphate, for DNA polymerase and incorporation into DNA. The reduction in intracellular concentrations of deoxycytidine triphosphate induced by gemcitabine diphosphate actually enhances the incorporation of gemcitabine triphosphate into DNA, a mechanism referred to as ''self-potentiation.'' Following incorporation of gemcitabine triphosphate into the DNA chain, a single additional nucleotide, a normal base pair, is added and DNA synthesis is terminated, resulting in apoptosis (programmed cell death). DNA polymerase ? is unable to recognize the abnormal (gemcitabine) nucleotide and repair the DNA strand as a result of masking by the terminal normal base pair nucleotide (masked chain termination). This inability to recognize and excise the abnormal nucleotide results in a prolonged intracellular half-life of gemcitabine compared with other nucleoside analogs such as cyta

Pharmacodynamics

Gemcitabine is a nucleoside analog that mediates its antitumour effects by promoting apoptosis of malignant cells undergoing DNA synthesis. More specifically, it blocks the progression of cells through the G1/S-phase boundary. Gemcitabine demonstrated cytotoxic effects against a broad range of cancer cell lines _in vitro_. It displayed schedule-dependent antitumour activity in various animal models and xenografts from human non-small cell lung cancer (NSCLC) and pancreatic cancer. Therefore, the antineoplastic effects of gemcitabine are enhanced through prolonged infusion time rather than higher dosage. Gemcitabine inhibited the growth of human xenografts from carcinoma of the lung, pancreas, ovaries, head and neck, and breast. In mice, gemcitabine inhibited the growth of human tumour xenografts from the breast, colon, lung or pancreas by 69 to 99%. In clinical trials of advanced NSCLC, gemcitabine monotherapy produced objective response rates ranging from 18 to 26%, with a median duration of response ranging from 3.3 to 12.7 months. Overall median survival time was 6.2 to 12.3 months. The combined use of cisplatin and gemcitabine produced better objective response rates compared to monotherapy. In patients with advanced pancreatic cancer, objective response rates in patients ranged from 5.to 12%, with a median survival duration of 3.9 to 6.3 months. In Phase II trials involving patients with metastatic breast cancer, treatment with gemcitabine alone or with adjuvant chemotherapies resulted in response rate ranging from 13 to 42% and median survival duration ranging from 11.5 to 17.8 months. In metastatic bladder cancer, gemcitabine has a response rate 20 to 28%. In Phase II trials of advanced ovarian cancer, patients treated with gemcitabine had response rate of 57.1%, with progression free survival of 13.4 months and median survival of 24 months. Gemcitabine causes dose-limiting myelosuppression, such as anemia, leukopenia, neutropenia, and thrombocytopenia; however, events leading to discontinuation tend to occur less than 1% of the patients. Gemcitabine can elevate ALT, AST and alkaline phosphatase levels.

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.