Iver-Tec

Indications

• Onchocerciasis (river blindness)
• Strongyloidiasis
• Scabies (especially hyperkeratotic or crusted scabies)
• Lymphatic filariasis
• Other helminth infections

Dosage

Children: Child 6 months–17 years: 100 mg for 1 dose;

Adults: Adult: Initially 1 mg/kg daily on the first day, then increased to 6 mg/kg daily in divided doses, gradually increased over 3 days. Maximum 9 mg/kg per day. For scabies, 100 mg for 1 dose; if reinfection occurs, a second dose may be given after 2 weeks.

Mechanism of action

Ivermectin binds selectively to glutamate-gated chloride channels, leading to increased permeability of the cell membrane to chloride ions. This results in hyperpolarization of the nerve or muscle cells in the parasites, causing paralysis and death. It also interacts with other chloride channels, which may contribute to its antiparasitic effects.

Pharmacodynamics

Ivermectin exhibits broad-spectrum activity against a variety of parasites, including nematodes and arthropods. Its effectiveness is attributed to its ability to paralyze and kill parasites, thus facilitating their expulsion from the host. The drug has a long half-life, allowing for effective dosing regimens, and it is generally well-tolerated in patients.

Pharmacokinetics

Ivermectin is rapidly absorbed following oral administration, with peak plasma concentrations occurring within 4 to 6 hours. It is extensively distributed throughout the body, including the central nervous system. The drug undergoes hepatic metabolism, primarily via cytochrome P450, and is eliminated with a half-life of approximately 18 hours. Excretion occurs mainly in the feces, with a smaller proportion eliminated in urine.

Contra-indications

• Blood disorders
• Epilepsy
• Sjögren’s syndrome

Adverse effects

• Diarrhoea
• Dizziness
• Headache
• Influenza-like illness
• Insomnia
• Myalgia
• Nausea
• Rash
• Seizure
• Taste alteration
• Vomiting
• Skin reactions
• Abnormal sensation in eye
• Anaemia
• Appetite decrease
• Asthenia
• Asthma exacerbated
• Chest discomfort
• Confusion
• Conjunctival haemorrhage
• Constipation
• Gastrointestinal discomfort
• Headache
• Hepatitis
• Hypotension
• Joint disorders
• Leukopenia
• Myalgia
• Nausea
• Oedema
• Pain
• Psychiatric disorder
• Severe cutaneous adverse reactions
• Stupor
• Tachycardia
• Tremor
• Urinary incontinence
• Vertigo

Interactions

• Coumarins: Unknown (increases anticoagulant effect)
• Levamisole: Unknown (increases exposure)

Precautions

• Use with caution in hepatic impairment
• Avoid sun exposure when using topical formulations

Pregnancy

Embryotoxic in animal studies, avoid if possible.

Breast-feeding

Manufacturer advises avoid-limited information available; ensure infant does not come in contact with treated areas.

Storage

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

Formulations

• Tablets
• Topical formulation

Indications

• Constipation
• Bowel cleansing

Dosage

Children: Child 1–11 months: 1 g as required, Child 1–11 years: 2 g as required, Child 12–17 years: 4 g as required.

Adults: 4 g as required, usually administered rectally.

Mechanism of action

When administered rectally, glycerol exerts a hygroscopic and/or local irritant action, drawing water from the tissues into the feces and reflexively stimulating evacuation. It decreases intraocular pressure by creating an osmotic gradient between the blood and intraocular fluid, causing fluid to move from the aqueous and vitreous humors into the bloodstream. Glycerol is classified as a hyperosmotic laxative and may also have lubricating and fecal softening effects.

Pharmacodynamics

Glycerol is commonly classified as an osmotic laxative, acting through its local irritant effects and possibly having lubricating and fecal softening actions. Glycerol suppositories usually produce effects within 15 to 30 minutes, providing quick relief from constipation.

Pharmacokinetics

Glycerol is rapidly absorbed through the gastrointestinal tract. It is metabolized in the liver and other tissues, with a half-life that varies depending on the route of administration. Following rectal administration, glycerol is primarily excreted in urine. The pharmacokinetics may vary based on dosage forms and individual patient factors.

Contra-indications

• Acute abdominal conditions
• Acute inflammatory bowel disease
• Intestinal obstruction
• Severe dehydration

Adverse effects

• Abdominal cramps
• Asthenia
• Gastrointestinal disorders
• Hypermagnesaemia
• Skin reactions
• Urine discolouration

Precautions

• Avoid prolonged contact with skin, especially in incontinent patients or infants wearing nappies due to the risk of irritation and excoriation.
• Excessive use may cause diarrhea and related effects such as hypokalaemia.

Pregnancy

Manufacturers advise avoidance due to limited information available.

Breast-feeding

Manufacturers advise avoidance as there is no information available.

Storage

Store at room temperature, away from direct sunlight.

Formulations

• Glycerol 1g suppositories
• Glycerol 2g suppositories
• Glycerol 4g suppositories
• Glycerol oral suspension

Indications

• Disinfectant
• Preservative
• Sterilization of medical instruments
• Formalin for histology and pathology specimens

Dosage

Children: Refer to local guidelines and recommendations, as doses may vary based on the specific clinical situation and formulation used.

Adults: Refer to local guidelines and recommendations, as doses may vary based on the specific clinical situation and formulation used.

Mechanism of action

Formaldehyde acts primarily as a cross-linking agent, covalently binding to proteins and nucleic acids. This mechanism is responsible for its effectiveness as a preservative and disinfectant, as it disrupts cellular metabolism and integrity in microorganisms, leading to cell death.

Pharmacodynamics

The pharmacodynamics of formaldehyde involves its ability to inactivate proteins and DNA through cross-linking, which interferes with cellular functions. This action results in its antimicrobial and preservative effects, although it also contributes to toxicity. The compound can elicit inflammatory responses in tissues and has been associated with respiratory irritations and carcinogenic effects upon prolonged exposure.

Pharmacokinetics

Formaldehyde is rapidly absorbed via inhalation and dermal routes, and it is metabolized mainly by the enzyme formaldehyde dehydrogenase to formic acid, which is then converted to carbon dioxide and water. The elimination half-life in the body is relatively short due to its rapid metabolism. Formaldehyde is distributed widely in body tissues, but due to its reactivity, it does not accumulate significantly.

Pregnancy

Safety in pregnancy has not been established.

Breast-feeding

It is unknown whether this drug is excreted in human milk.

Storage

Store at room temperature, away from moisture and heat.

Dosage

Children: Refer to the BNF for Children for appropriate dosing information in paediatric cases, especially in instances of overdose.

Adults: Refer to the BNF for specific dosing information based on clinical circumstances, particularly in cases of overdose.

Mechanism of action

Ethylene glycol is metabolized by alcohol dehydrogenase to glycoaldehyde, which is subsequently converted to glycolic, glyoxylic, and oxalic acids. These metabolites contribute to anion gap metabolic acidosis and are responsible for tissue injury through the formation of insoluble calcium oxalate crystals.

Pharmacodynamics

The toxicity of ethylene glycol arises from its metabolites, particularly glycolic and oxalic acids. These compounds induce metabolic acidosis, lead to renal failure through calcium oxalate crystal deposition in the kidneys, and can cause neurological impairment. The anion gap increases due to the accumulation of these acids, leading to complications such as cardiovascular instability and potential multi-organ failure.

Pharmacokinetics

Ethylene glycol is rapidly absorbed after oral ingestion. It undergoes first-pass metabolism primarily in the liver, where it is converted into its toxic metabolites. The elimination half-life of ethylene glycol varies but is generally prolonged in cases of renal impairment. Renal excretion of metabolites contributes to the duration of toxicity, necessitating prompt medical intervention in cases of overdose.

Adverse effects

• Metabolic acidosis
• Renal failure
• CNS depression
• Hypocalcemia
• Cardiovascular collapse
• Pulmonary edema

Precautions

• Use with caution in patients with renal impairment
• Monitor for signs of metabolic acidosis
• Evaluate electrolyte levels, particularly calcium

Pregnancy

There is limited data on the safety of ethylene glycol in pregnancy. It should only be used if clearly needed.

Breast-feeding

It is unknown if ethylene glycol is excreted in human milk. Caution is advised.

Storage

Store in a tightly closed container at room temperature, away from heat and moisture.

Formulations

• Liquid

Indications

• Used as a solvent for oral, injectable, and topical medications
• Involved in the formulation of certain anesthetics
• Used in cosmetic and personal care products

Dosage

Children: Refer to specific product labeling for dosing information, as it varies depending on the formulation and intended use.

Adults: Refer to specific product labeling for dosing information, as it varies depending on the formulation and intended use.

Mechanism of action

Propylene glycol acts primarily as a solvent and carrier for drugs, facilitating their absorption and bioavailability. It enhances the solubility of hydrophobic drugs in aqueous solutions, which aids in the formulation of injectable and oral dosage forms. Additionally, it may also have mild antimicrobial properties, contributing to the preservation of formulations.

Pharmacodynamics

As a low toxicity solvent, propylene glycol does not exert significant pharmacological effects on its own. However, its role in drug formulation can influence the pharmacodynamics of the active pharmaceutical ingredients (APIs) it carries. The effectiveness of the drug can be enhanced due to improved solubility and absorption, ultimately affecting the drug's therapeutic effects.

Pharmacokinetics

Propylene glycol is readily absorbed from the gastrointestinal tract and distributed throughout the body. It is metabolized primarily in the liver via the enzyme alcohol dehydrogenase to lactic acid and pyruvate, which are then utilized in energy metabolism. The elimination half-life of propylene glycol is relatively short, and it is excreted mainly through urine as non-toxic metabolites. Its pharmacokinetic profile may vary based on the route of administration and the presence of other drugs.

Pregnancy

Propylene is generally considered safe during pregnancy as it is not known to cause harm to the developing fetus, but caution should be exercised and it should only be used if clearly needed.

Breast-feeding

Propylene is typically regarded as safe during breastfeeding, but it is advisable to consult a healthcare provider before use.

Storage

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

Mechanism of action

When administered rectally, glycerin exerts a hygroscopic and/or local irritant action, drawing water from the tissues into the feces and reflexively stimulating evacuation. Glycerin decreases intraocular pressure by creating an osmotic gradient between the blood and intraocular fluid, causing fluid to move out of the aqueous and vitreous humors into the bloodstream. Glycerin (glycerol) and sorbitol are hyperosmotic laxatives. When administered rectally, glycerin and sorbitol exert a hygroscopic and/or local irritant action, drawing water from the tissues into the feces and reflexly stimulating evacuation. The extent to which the simple physical distention of the rectum and the hygroscopic and/or local irritant actions are responsible for the laxative effects of some of these drugs is not known. Only extremely high oral doses of sorbitol (25 g daily) or glycerin exert laxative action. /Glycerin/ decreases intraocular pressure by creating an osmotic gradient between the blood and intraocular fluid, causing fluid to move out of the aqueous and vitreous humors into the bloodstream. The physicochemical effects of a series of alkanols, alkanediols and glycerol on erythrocyte shape and hemolysis at 4 and 20 degrees C were examined. We calculated the dielectric constant of the incubation medium, Ds, and the dielectric constant of the erythrocyte membrane Dm in the presence of organic solutes. The ratio Ds/Dm = -38.48 at 20 degrees C defines the normal biconcave shape in a medium without hemolytic agents. A decrease in Ds/Dm favors externalization or internalization with consequent hemolysis. Alkanols and alkanediols convert biconcave erythrocytes into echinocytes, which is accompanied by an increase in the projected surface area. Glycerol converts biconcave erythrocytes into stomatocytes, which was accompanied by a marginal decrease in the projected surface area. Progressive externalization in alkanols and alkanediols or internalization in glycerol resulted in a decrease in the projected surface area and the formation of smooth spheres. The degree of shape change induced was related to the degree of hemolysis and the ratio Ds/Dm. A decrease in temperature reduced both the degree of shape change and hemolysis. .../Thus/ physicochemical toxicity may be a result of a temperature dependent hydrophobic interaction between the organic solutes and the membrane and is best interpreted by the ability of the solutes to change Ds and Dm.

Pharmacodynamics

Glycerin is commonly classified as an osmotic laxative but may act additionally or alternatively through its local irritant effects; it may also have lubricating and fecal softening actions. Glycerin suppositories usually work within 15 to 30 minutes.

Mechanism of action

Ethylene glycol is metabolized by alcohol dehydrogenase to glycoaldehyde, which is then metabolized to glycolic, glyoxylic, and oxalic acids. These acids, along with excess lactic acid are responsible for the anion gap metabolic acidosis. Oxalic acid readily precipitates with calcium to form insoluble calcium oxalate crystals. Tissue injury is caused by widespread deposition of oxalate crystals and the toxic effects of glycolic and glyoxylic acids.