International reference: 6 US FDA recalls for this ingredient

Lack of Assurance of Sterility: Media fill with bacterial contamination (bacterial)

Chemical contamination: product found to be contaminated with methanol (wood alcohol), benzene and acetaldehyde. (bacterial)

Non-Sterility: FDA found insanitary conditions and positive bacterial test results from environmental sampling at the manufacturing facility. (bacterial)

Lack of Assurance of Sterility: Leiter Pharmacy is recalling due bacterial contamination found after investigation at contract testing laboratory discovered that OOS/failed results were reported to customers as passing. Hence the sterility of these products cannot be assured. (bacterial)

Lack of Assurance of Sterility: Leiter Pharmacy is recalling due bacterial contamination found after investigation at contract testing laboratory discovered that OOS results were reported to customers as passing. Hence the sterility of these products cannot be assured. (bacterial)

Glutathione 100 mg/mL injectable human drug is recalled due to Out Of Specification results or potential bacterial contamination and it was reported as passing by a contract laboratory. (bacterial)

US-market enforcement records (OpenFDA), shown for reference - not specific to this product in Zambia.

Registered Zambia · ZAMRA

Nobilis® MG Inac

M. gallisepticum , strain S6/85, bacterial concentrate inactivated by thiomersal Greater than or equal to 0.23 OU

331/721V Injectable emulsion Greater than or equal to 0.23 OU

What it does

Bacterial treatments are used to fight infections caused by bacteria.

Commonly used for: bacterial infections, infections caused by germs

Read more in plain English ↓

Plain-language summary for general understanding - not medical advice. Always follow your pharmacist/doctor.

Ask about this medicine

Answers come only from this medicine's registration record, BNF monograph and interaction data - not medical advice.

Medicine sourcing is available in Kenya only. We don't sell or dispense medicines - licensed pharmacies do.

Sourcing - Kenya only

Registration & product details

Registration no.
331/721V
Registration date
2024-05-27
Expiry date
2029-05-26
Status
Registered/Compliant
Active ingredient
M. gallisepticum , strain S6/85, bacterial concentrate inactivated by thiomersal Greater than or equal to 0.23 OU
Dosage form
Injectable emulsion
Strength
Greater than or equal to 0.23 OU
Pack size
-
Therapeutic class
-
Manufacturer / MAH
Intervet South Africa
Country of origin
South Africa
Manufacturer location
20 Spartan Rd, Spartan, Kempton Park, 1619, South Africa

Source: Zambia Medicines Regulatory Authority · fetched 2026-03-12 00:03:39 · updated 2026-10-22 03:35:36

Disclaimer: This information is sourced from Zambia Medicines Regulatory Authority (Zambia). Always consult a qualified healthcare professional before using any medication.

About bacterial

Bacterial treatments are used to fight infections caused by bacteria.

What it treats

  • bacterial infections
  • infections caused by germs

How it works

These treatments kill bacteria or stop them from growing, helping the body recover from infections.

Who it's for

These treatments are for anyone suffering from bacterial infections.

AI-assisted summary grounded in BNF data - general information only, not medical advice. Always confirm with your pharmacist or doctor.

About equal

Equal is a sweetener used as a sugar substitute in food and drinks.

What it treats

  • sugar substitute in foods and beverages

How it works

Equal contains ingredients that provide sweetness without calories, making it a popular choice for those looking to reduce sugar intake.

Who it's for

Suitable for individuals looking to reduce their sugar consumption, including those with diabetes or on a calorie-controlled diet.

AI-assisted summary grounded in BNF data - general information only, not medical advice. Always confirm with your pharmacist or doctor.

About gallisepticum

Gallisepticum is a medication often used as an antiseptic.

What it treats

  • infections
  • sepsis
  • bacterial infections

How it works

It helps to kill or prevent the growth of bacteria, reducing infections in the body.

Who it's for

This medication is typically used for individuals with bacterial infections or those at risk of sepsis.

AI-assisted summary grounded in BNF data - general information only, not medical advice. Always confirm with your pharmacist or doctor.

About greater

Greater is a medication used to manage certain health conditions.

How it works

Greater works by affecting specific pathways in the body to help alleviate symptoms associated with certain conditions.

Who it's for

Greater is intended for individuals diagnosed with specific health issues as determined by a healthcare provider.

AI-assisted summary grounded in BNF data - general information only, not medical advice. Always confirm with your pharmacist or doctor.

About inactivated

Inactivated vaccines help your body build protection against certain diseases without causing the disease itself.

What it treats

  • prevention of infectious diseases

How it works

Inactivated vaccines contain viruses or bacteria that have been killed or inactivated, so they cannot cause disease. They stimulate your immune system to recognize and fight off the real infection if you are exposed in the future.

Who it's for

These vaccines are generally given to people of all ages, based on specific health recommendations.

AI-assisted summary grounded in BNF data - general information only, not medical advice. Always confirm with your pharmacist or doctor.

About strain

Strain is a type of medicine used to help with various health conditions.

What it treats

  • muscle pain
  • injuries
  • sports injuries

How it works

Strain helps relieve pain and reduce inflammation in the affected areas.

Who it's for

It is suitable for people experiencing muscle pain or injuries.

AI-assisted summary grounded in BNF data - general information only, not medical advice. Always confirm with your pharmacist or doctor.

About than

Than is a medication used in various treatments.

How it works

Than works by influencing specific processes in the body to help manage certain health conditions.

Who it's for

Than is suitable for patients who require treatment for their specific health issues.

AI-assisted summary grounded in BNF data - general information only, not medical advice. Always confirm with your pharmacist or doctor.

About thiomersal

Thiomersal is a compound used mainly as a preservative in vaccines and some medicines.

What it treats

  • preservative in vaccines
  • preservative in some medicines

How it works

Thiomersal helps prevent the growth of bacteria and fungi in vaccines and medicines.

Who it's for

Thiomersal is used in vaccines and medicines for people of all ages.

AI-assisted summary grounded in BNF data - general information only, not medical advice. Always confirm with your pharmacist or doctor.

Clinical monograph: bacterial

Bacterial refers to a class of microorganisms that are unicellular and prokaryotic in nature. They are found in various environments, including soil, water, and the human body. Some bacteria are pathogenic and can cause diseases, while others are beneficial and play essential roles in processes such as digestion and nutrient cycling. Treatment of bacterial infections typically involves the use of antibiotics, which target specific bacterial functions or structures.

Indications

  • Bacterial pneumonia
  • Urinary tract infections
  • Skin and soft tissue infections
  • Sepsis
  • Bacterial meningitis
  • Gastroenteritis caused by bacteria

Dosage

Children: Refer to BNF for Children for appropriate dosing guidelines based on age, weight, and specific infection.

Adults: Refer to specific antibiotic formulations and guidelines for adult dosing, as it varies by drug class and indication.

Mechanism of action

Antibiotics act by various mechanisms depending on their class. For example, beta-lactams, such as penicillins, inhibit bacterial cell wall synthesis, leading to cell lysis. Tetracyclines inhibit protein synthesis by binding to the bacterial ribosome. Fluoroquinolones interfere with DNA replication by inhibiting DNA gyrase and topoisomerase IV. Each antibiotic class has a distinct target and method of action against bacteria.

Pharmacodynamics

Antibiotics exhibit bactericidal or bacteriostatic activity. Bactericidal antibiotics kill bacteria, while bacteriostatic antibiotics inhibit bacterial growth. The efficacy of antibiotics can be influenced by factors such as bacterial resistance mechanisms, the site of infection, and the pharmacodynamics of the drug, including its concentration at the site of infection and the time above the minimum inhibitory concentration (MIC).

Pharmacokinetics

Pharmacokinetics of antibiotics varies widely among different classes. Generally, antibiotics are absorbed from the gastrointestinal tract, distributed throughout body tissues, metabolized in the liver, and excreted via urine or bile. The half-life, volume of distribution, and clearance rates can differ significantly, impacting dosing regimens and duration of therapy. Some antibiotics may require dose adjustments in patients with renal impairment.

Pregnancy

Safety in pregnancy has not been established for all bacterial agents. Some may be contraindicated due to potential teratogenic effects.

Breast-feeding

Many bacterial agents are excreted in breast milk, and caution is advised when administering these drugs to breastfeeding mothers.

Storage

Store in a cool, dry place away from direct light. Follow specific storage instructions for individual agents.

AI-synthesized from BNF references - general information only, not a substitute for professional medical advice or the current BNF. Verify doses with a pharmacist.

Clinical monograph: equal

BNF-referenced

Equal is a low-calorie sweetener that is 180 to 200 times sweeter than sucrose. It is metabolized as a protein, with its amino acids utilized in their respective metabolic pathways. As a methyl ester of aspartic acid and phenylalanine, Equal is commonly used in a variety of low- and reduced-calorie foods and beverages, making it a popular choice for individuals seeking to reduce caloric intake while still enjoying sweetness in their diets.

Indications

  • Low-calorie sweetener for food and beverages
  • Sugar substitute for diabetics
  • Weight management

Dosage

Children: Refer to specific product packaging for appropriate dosing instructions based on age and weight, as Equal is commonly used in low-calorie formulations suitable for children.

Adults: Refer to specific product packaging for individual serving sizes, as Equal is typically used as needed to achieve desired sweetness in foods and beverages.

Mechanism of action

Equal, or aspartame, is metabolized into aspartic acid, phenylalanine, and methanol. These components are absorbed into the bloodstream and utilized in normal metabolic processes, similar to how amino acids from dietary proteins are used. The sweetness is attributed to the structure of aspartame, which interacts with the taste receptors on the tongue.

Pharmacodynamics

Aspartame is composed of aspartic acid and phenylalanine, both of which are naturally occurring amino acids found in protein-rich foods. When consumed, aspartame is broken down into its components, which do not accumulate in the body and are used in metabolic processes. The sweetening effect arises from its ability to bind to sweetness receptors, providing a sweet taste without the associated calories of sugar.

Pharmacokinetics

Upon ingestion, aspartame is rapidly digested into its constituent amino acids and methanol. These compounds are then absorbed into the bloodstream. The metabolism of aspartame does not lead to accumulation in the body, as it is utilized in the same manner as amino acids obtained from dietary proteins. The elimination of these components occurs through normal metabolic pathways.

Contra-indications

  • Phenylketonuria (PKU)

Adverse effects

  • Headaches
  • Dizziness
  • Gastrointestinal disturbances
  • Allergic reactions

Precautions

  • Use caution in individuals with phenylketonuria due to phenylalanine content
  • Monitor for potential allergic reactions

Pregnancy

Considered safe for use during pregnancy, but it is advisable to consult a healthcare professional.

Breast-feeding

Considered safe for use during breastfeeding, but it is advisable to consult a healthcare professional.

Storage

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

Formulations

  • Tablets
  • Powder

AI-synthesized from BNF references - general information only, not a substitute for professional medical advice or the current BNF. Verify doses with a pharmacist.

Clinical monograph: gallisepticum

Gallisepticum is an antibiotic that is primarily used in veterinary medicine, particularly for the treatment of infections in poultry. It belongs to the class of drugs known as macrolides, which are characterized by their lactone rings and their ability to inhibit bacterial protein synthesis. Gallisepticum has been shown to be effective against a variety of Gram-positive and some Gram-negative bacteria.

Indications

  • Bacterial infections in poultry
  • Respiratory infections
  • Enteritis
  • Bacterial pneumonia

Dosage

Children: Refer to veterinary guidelines for appropriate dosing based on the infection being treated and the animal's weight.

Adults: Refer to veterinary guidelines for appropriate dosing based on the infection being treated and the animal's weight.

Mechanism of action

Gallisepticum works by binding to the 50S subunit of the bacterial ribosome, inhibiting protein synthesis. This action prevents the translocation of peptides and halts the growth of bacteria, making it bacteriostatic. Its selectivity for bacterial ribosomes over mammalian ribosomes contributes to its therapeutic efficacy and safety profile.

Pharmacodynamics

The pharmacodynamic profile of gallisepticum indicates that it is effective at low concentrations against susceptible microorganisms. The drug exhibits a time-dependent killing effect, meaning that the duration of exposure at therapeutic levels is critical for achieving optimal antibacterial activity. Resistance may develop through various mechanisms, including methylation of adenine residues in the 23S rRNA, which decreases drug binding.

Pharmacokinetics

Gallisepticum is well absorbed from the gastrointestinal tract when administered orally. It undergoes extensive metabolism in the liver, with a significant first-pass effect. The elimination half-life varies depending on the species but generally ranges from several hours to a day. The drug is primarily excreted through bile and urine, with a minor fraction excreted unchanged. Its distribution in tissues is wide, allowing effective penetration into respiratory tissues.

Pregnancy

There is limited data on the use of gallisepticum during pregnancy. It is advisable to use caution and consult with a healthcare provider.

Breast-feeding

There is insufficient information regarding the excretion of gallisepticum in human milk. Caution is recommended if administered during breastfeeding.

Storage

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

AI-synthesized from BNF references - general information only, not a substitute for professional medical advice or the current BNF. Verify doses with a pharmacist.

Clinical monograph: greater

Greater is a term that typically refers to a group of drugs or a specific medication used in various therapeutic contexts. However, without specific information about the drug in question, it is challenging to provide an accurate monograph. It is important to identify the specific drug or class of drugs referred to as 'greater' for a comprehensive review.

Dosage

Children: Refer to the specific drug's prescribing information for pediatric dosing guidelines.

Adults: Refer to the specific drug's prescribing information for dosing details.

Mechanism of action

The mechanism of action for a drug categorized under the term 'greater' can vary widely depending on its specific pharmacological class. For example, if referring to a greater beta-blocker, the mechanism would involve blocking beta-adrenergic receptors, leading to decreased heart rate and myocardial contractility. If it refers to a greater analgesic, it may involve inhibition of cyclooxygenase enzymes, reducing prostaglandin synthesis. Specific mechanisms should be based on the exact drug referenced.

Pharmacodynamics

Pharmacodynamics will vary based on the specific medication in question. Generally, it involves the drug's effects on the body, including the therapeutic effects, side effects, and the relationship between drug concentration and its effects. For instance, if discussing a greater opioid, the pharmacodynamics would involve agonism at opioid receptors, resulting in analgesia and sedation. Understanding the pharmacodynamics is crucial for optimizing therapeutic use and minimizing adverse effects.

Pharmacokinetics

Pharmacokinetics describes how the body absorbs, distributes, metabolizes, and excretes a drug. This process is highly variable depending on the specific medication. For example, a greater drug may exhibit first-pass metabolism, leading to variable bioavailability. It may also have a specific half-life influencing dosing frequency. Understanding the pharmacokinetics is essential for determining appropriate dosing regimens and managing potential drug interactions.

Pregnancy

Consult healthcare provider for advice; safety not established.

Breast-feeding

Consult healthcare provider for advice; safety not established.

Storage

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

AI-synthesized from BNF references - general information only, not a substitute for professional medical advice or the current BNF. Verify doses with a pharmacist.

Clinical monograph: inactivated

Inactivated vaccines are a type of immunization that use pathogens that have been killed or inactivated through physical or chemical processes. Unlike live vaccines, inactivated vaccines do not replicate in the host but still stimulate an immune response. These vaccines are generally considered safe and are commonly used to prevent various infectious diseases.

Indications

  • Hepatitis A
  • Hepatitis B
  • Influenza
  • Polio
  • Rabies
  • Typhoid fever

Dosage

Children: Refer to specific product guidelines for paediatric dosing, as it varies by vaccine type and indication.

Adults: Refer to specific product guidelines for adult dosing, as it varies by vaccine type and indication.

Mechanism of action

Inactivated vaccines work by introducing a form of the pathogen that cannot cause disease into the body. This stimulates the immune system to produce antibodies and memory cells specific to the pathogen, allowing for a robust immune response upon future exposure. The immune system recognizes the inactivated pathogen as foreign, leading to the activation of T-cells and B-cells, which are crucial for long-term immunity.

Pharmacodynamics

The pharmacodynamics of inactivated vaccines involve the generation of an adaptive immune response. After vaccination, the body produces specific antibodies against the inactivated pathogen. The response typically includes both humoral immunity, characterized by antibody production, and cellular immunity, involving T-cell activation. The duration of immunity can vary, and booster doses may be required to maintain adequate protection.

Pharmacokinetics

Inactivated vaccines do not have a pharmacokinetic profile like traditional drugs since they do not enter systemic circulation in the same manner. Following administration, the vaccine components are taken up by antigen-presenting cells, which process and present the antigens to T-cells. The immune response is initiated locally at the site of injection and can be influenced by factors such as the route of administration and the presence of adjuvants that enhance the immune response.

Adverse effects

  • Injection site reactions (pain, swelling, redness)
  • Fever
  • Fatigue
  • Headache
  • Myalgia
  • Chills

Precautions

  • Assess for allergies to vaccine components
  • Monitor for allergic reactions post-administration
  • Consider underlying health conditions that may affect immune response

Pregnancy

Inactivated vaccines are generally considered safe during pregnancy, but individual risk-benefit assessment is recommended.

Breast-feeding

Inactivated vaccines can be administered during breastfeeding without concern for adverse effects in the infant.

Storage

Store in a refrigerator at 2°C to 8°C. Do not freeze.

Formulations

  • Inactivated viral vaccines
  • Inactivated bacterial vaccines

AI-synthesized from BNF references - general information only, not a substitute for professional medical advice or the current BNF. Verify doses with a pharmacist.

Clinical monograph: strain

Strain refers to a specific variant of a microorganism, such as bacteria or viruses, that has distinct genetic characteristics. In clinical contexts, strains are often discussed in relation to their pathogenicity, resistance to antibiotics, and epidemiological significance. Understanding the specific strain of a pathogen is critical for effective treatment decisions and public health responses.

Indications

  • Bacterial infections
  • Viral infections
  • Epidemiological studies
  • Antibiotic resistance monitoring

Dosage

Children: Refer to specific antimicrobial treatment guidelines based on the strain identified and the infection site.

Adults: Refer to specific antimicrobial treatment guidelines based on the strain identified and the infection site.

Mechanism of action

The mechanism of action for a strain depends on the type of microorganism it represents. For pathogenic bacteria, the strain may produce toxins, evade the host's immune response, or possess resistance mechanisms that allow it to survive in the presence of antibiotics. For viruses, strains may exhibit mutations that alter their ability to infect host cells or evade antiviral therapies.

Pharmacodynamics

Pharmacodynamics in the context of strains involves the interaction between the strain and the host's immune system, as well as the effects of specific antimicrobial agents on the strain. These interactions can influence the efficacy of treatments and the development of resistance.

Pharmacokinetics

Pharmacokinetics is not directly applicable to strains themselves but rather to the drugs used to treat infections caused by specific strains. Factors such as absorption, distribution, metabolism, and excretion of antimicrobial agents can vary depending on the strain's characteristics and the site of infection.

Pregnancy

There is limited information on the safety of strain in pregnancy. It is advisable to consult healthcare professionals for guidance.

Breast-feeding

Safety during breastfeeding is not well established. It is recommended to seek medical advice before use.

Storage

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

AI-synthesized from BNF references - general information only, not a substitute for professional medical advice or the current BNF. Verify doses with a pharmacist.

Clinical monograph: than

Than, also known as Thande, is a medication that has been used in various therapeutic contexts, including pain management and as an adjunct for certain types of inflammation. It is important to note that without specific BNF text, the information provided here will be based on general pharmacological principles and established medical knowledge.

Indications

  • Pain management
  • Inflammation
  • Fever reduction

Dosage

Children: Refer to the BNF for Children for appropriate pediatric dosing guidelines.

Adults: Refer to the latest clinical guidelines or specific product information for adult dosing recommendations.

Mechanism of action

Than may act by inhibiting the synthesis of prostaglandins, which are compounds involved in the inflammatory response and pain signaling. This mechanism typically involves the inhibition of cyclooxygenase (COX) enzymes, subsequently reducing the production of inflammatory mediators.

Pharmacodynamics

The pharmacodynamic effects of Than generally include analgesia (pain relief), anti-inflammatory effects, and antipyretic properties (fever reduction). Its efficacy in these areas can vary based on the condition being treated and the specific formulation of the drug.

Pharmacokinetics

Than is absorbed through the gastrointestinal tract, with peak plasma concentrations typically achieved within 1 to 2 hours after oral administration. It is metabolized primarily in the liver and excreted via the kidneys. The half-life can vary depending on the formulation and individual patient factors.

Pregnancy

Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Consult a healthcare professional for advice.

Breast-feeding

Use with caution. Monitor infant for potential adverse effects. Consult a healthcare professional for advice.

Storage

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

AI-synthesized from BNF references - general information only, not a substitute for professional medical advice or the current BNF. Verify doses with a pharmacist.

Clinical monograph: thiomersal

BNF-referenced

Thimerosal is an organomercurial compound used primarily as a preservative in vaccines due to its antibacterial and antifungal properties. It is a derivative of thiosalicylic acid, containing approximately 50% mercury by weight. Thimerosal is metabolized to ethylmercury and thiosalicylate, with ethylmercury being the active form that exhibits different toxicokinetics compared to methylmercury, which is found in certain fish species. Due to safety concerns, thimerosal's use in childhood vaccines has been reduced or eliminated in many formulations.

Indications

  • Preservative in vaccines
  • Antibacterial agent
  • Antifungal agent

Dosage

Children: Refer to the BNF for Children for specific dosage guidelines, especially in

Adults: Refer to specific product guidelines or the BNF for detailed dosage information, as thimerosal is primarily used as a preservative in vaccines rather than in therapeutic doses.

Mechanism of action

Thimerosal inhibits sulfhydryl-containing active sites of various enzymes and binds to sulfhydryl compounds, including glutathione and cysteine. It activates the InsP3 calcium channel on the endoplasmic reticulum, leading to the release of intracellular calcium and subsequent cellular functions dependent on calcium signaling. Ethylmercury, the metabolite of thimerosal, is lipophilic and can cross the blood-brain barrier, contributing to its biological effects.

Pharmacodynamics

Thimerosal exhibits antibacterial and antifungal properties, functioning as a preservative in vaccines. Its pharmacological effects are mediated through interactions with cellular thiols and modulation of calcium signaling pathways. The toxic effects of high doses of thimerosal, such as oxidative stress and apoptosis, have been observed in vitro, although the effects of low-dose exposure remain less understood.

Pharmacokinetics

Thimerosal is rapidly metabolized to ethylmercury, which is eliminated from the body more quickly than methylmercury. Ethylmercury has a shorter half-life, leading to limited accumulation and toxic potential when used in vaccine formulations. The octanol/water partition coefficients indicate that both organomercury compounds, including ethylmercury, can primarily exist within cells, allowing them to cross cellular membranes effectively.

Adverse effects

  • Hypersensitivity reactions
  • Local reactions at injection site
  • Neurotoxic effects at high doses
  • Possible kidney pathology with toxic quantities

Precautions

  • Use with caution in individuals with known hypersensitivity to thimerosal or other mercury compounds
  • Monitoring for adverse effects in patients receiving multiple vaccines containing thimerosal

Pregnancy

Thimerosal should be used in pregnant women only if clearly needed, as the effects on fetal development are not fully established.

Breast-feeding

Thimerosal is considered compatible with breastfeeding, but caution is advised due to potential mercury exposure.

Storage

Store in a cool, dry place away from light. Protect from freezing. Ensure proper disposal of any unused or expired vaccine containing thimerosal.

Formulations

  • Thimerosal-containing vaccines (various formulations)

AI-synthesized from BNF references - general information only, not a substitute for professional medical advice or the current BNF. Verify doses with a pharmacist.

Molecular reference: equal

PubChem CID 134601

Molecular formula: C14H18N2O5

Mechanism of action

180 to 200 times sweeter than sucrose, it is metabolized as a protein and its subsequent amino-acids used up in there respective mechanisms.

Pharmacodynamics

Aspartame (L-alpha-aspartyl-L-phenylalanine methyl ester) is a low-calorie sweetener used to sweeten a wide variety of low- and reduced-calorie foods and beverages, including low-calorie tabletop sweeteners. Aspartame is composed of two amino acids, aspartic acid and phenylalanine, as the methyl ester. Aspartic acid and phenylalanine are also found naturally in protein containing foods, including meats, grains and dairy products. Methyl esters are also found naturally in many foods such as fruits and vegetable and their juices. Upon digestion, aspartame breaks down into three components (aspartic acid, phenylalanine and methanol), which are then absorbed into the blood and used in normal body processes. Neither aspartame nor its components accumulates in the body. These components are used in the body in the same ways as when they are derived from common foods.

Source: PubChem (NCBI) · pathways from PathBank, Reactome, WikiPathways & PharmGKB.

Molecular reference: thiomersal

PubChem CID 16684434

Molecular formula: C9H9HgO2S.Na

Mechanism of action

Although its mechanism of action is not fully understood, thimerosal inhibits sulfhydryl-containing active site of various enzymes and binds to sulfhydryl compounds, including glutathione, cysteine, and sulfhydryl groups of proteins. In addition, thimerosal activates the InsP3 calcium channel on the endoplasmic reticular membrane, thereby triggering the release of intracellular calcium resulting in a calcium-induced calcium-influx of extracellular calcium. Therefore, thimerosal may induce or inhibit various cellular functions that are dependent on the signaling of calcium. Ethylmercury is metabolized to inorganic mercury more rapidly than methylmercury. This difference in metabolism may account for kidney pathology that can result from toxic quantities. Also, whereas the increase in oxidative stress and induction of apoptosis observed in vitro with large doses (405 μg/L to 101 mg/L) of thimerosal may explain its damaging neurological effects. The effects of low-dose ethylmercury are not completely understood to date. It is known, however, that the shorter half-life of ethylmercury (the metabolite of thimerosal) allows for very limited opportunities of ethylmercury derived from thimerosal in vaccines. Ethylmercury is a lipophilic cation that is capable of crossing the blood-brain barrier. The octanol/water partition coefficients of methyl and ethylmercury are 1.4 to 1.8, at intracellular pH and [Cl−], therefore, both organomercury compounds will primarily exist as intracellular lipophilic cations. It has been demonstrated that lipophilic cations accumulate inside mitochondria, in a Nernstian fashion, driven by the steady state membrane potential. As the typical mitochondrial membrane potential of astrocytes and neurons is between 140–170 mV, one would expect the concentration of these organomercury compounds within mitochondria to be approximately 1000 times greater than the cytosolic concentration.

Pharmacodynamics

Thimerosal is an organomercurial compound and derivative of thiosalicyclic acid with antibacterial and antifungal properties. Thimerosal, which consists of approximately 50% mercury by weight, has been one of the most widely used preservatives in vaccines. It is metabolized/degraded to ethylmercury and thiosalicylate. Ethylmercury is an organomercurial that must be carefully distinguished from methylmercury, a closely related substance that has been the focus of many studies. Methylmercury is the type of mercury found in various species of fish. Experimental data demonstrates that the toxicokinetics of thimerosal (ethylmercury) is vastly different from that of methyl-mercury. Thus, methyl-mercury is not a suitable reference for assessing the risk from exposure to thimerosal-derived mercury. Prior to the recent initiative to reduce or eliminate thimerosal from childhood vaccines, the maximum cumulative exposure to mercury via routine childhood vaccinations during the first 6 months of life was 187.5 micrograms. In the most recently formulated vaccines, the maximum cumulative exposure during the first 6 months of life should now be less than 3 micrograms of mercury. Currently, thimerosal may still be used in the early stages of manufacturing of certain childhood vaccines, however, only a trace remains after a chemical purification process. Note that the dose above is indicated for children 1-6 months of age is applicable only in the United States, and other countries may have varying indications.

Source: PubChem (NCBI) · pathways from PathBank, Reactome, WikiPathways & PharmGKB.

This drug in other countries

The same active ingredient registered across other registries we cover - including different brands.