TWINRIX ADULT VACCINE

Indications

• Pregnancy prevention
• Menstrual cycle regulation
• Management of dysmenorrhea
• Treatment of endometriosis
• Acne management (off-label use)
• Reduction of menstrual-related symptoms

Dosage

Children: Paediatric dosing for combined hormonal contraceptives is generally not established; refer to the BNF for Children for guidance based on individual patient needs and clinical considerations.

Adults: The dosage of combined hormonal contraceptives varies by formulation; follow the specific BNF guidelines for the chosen product.

Mechanism of action

Combined hormonal contraceptives work by suppressing the hypothalamic-pituitary-ovarian axis. Estrogen and progestin work together to inhibit the release of gonadotropins (LH and FSH) from the pituitary gland, preventing follicular development and ovulation. Additionally, progestin alters the cervical mucus to inhibit sperm passage and modifies the endometrium to reduce the likelihood of implantation.

Pharmacodynamics

The pharmacodynamic effects of combined hormonal contraceptives include the prevention of ovulation, changes in cervical mucus, and alterations in the endometrial lining. These effects lead to a significant reduction in the likelihood of pregnancy when taken as directed. The effectiveness can be influenced by factors such as adherence to the regimen and interactions with other medications.

Pharmacokinetics

Combined hormonal contraceptives are typically absorbed rapidly after oral administration. The bioavailability can be affected by the first-pass metabolism in the liver. Estrogens are primarily metabolized in the liver, while progestins undergo hepatic metabolism as well. The elimination half-lives vary by specific formulation but generally range from several hours to a few days. These hormones are excreted primarily via urine and feces.

Interactions

• cobicistat + combined hormonal contraceptives: Severe (decreases efficacy)
• combined hormonal contraceptives + lenalidomide: Severe (increases risk of venous thromboembolism)
• lorlatinib + combined hormonal contraceptives: Severe (decreases exposure)
• pitolisant + combined hormonal contraceptives: Severe (decreases efficacy)
• combined hormonal contraceptives + pomalidomide: Severe (increases risk of venous thromboembolism)
• combined hormonal contraceptives + thalidomide: Severe (increases risk of venous thromboembolism)
• combined hormonal contraceptives + tizanidine: Severe (increases exposure)
• combined hormonal contraceptives (containing ethinylestradiol + voxilaprevir with sofosbuvir and velpatasvir): Severe (increases risk of increased ALT concentrations)
• combined hormonal contraceptives alter the exposure to lamotrigine and lamotrigine + combined hormonal contraceptives: Moderate (decreases efficacy)
• combined hormonal contraceptives + erlotinib: Moderate (increases exposure)

Pregnancy

Combined hormonal contraceptives are generally contraindicated in pregnancy due to the potential risks to the fetus and increased risk of thromboembolism in pregnant individuals.

Breast-feeding

The use of combined hormonal contraceptives during breastfeeding is not recommended in the first few weeks postpartum, as they may affect milk production.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Indications

• Acute viral hepatitis
• Chronic hepatitis B
• Chronic hepatitis C
• Autoimmune hepatitis
• Alcoholic hepatitis
• Non-alcoholic fatty liver disease

Dosage

Children: Paediatric dosing also varies significantly based on the specific condition and medication. As with adult dosing, it is important to refer to the BNF for Children for specific recommendations.

Adults: Dosing for adult patients varies widely depending on the specific antiviral agent used and the type of hepatitis. It is essential to refer to specific guidelines or the BNF for precise dosing.

Mechanism of action

In viral hepatitis, the viruses typically enter liver cells and replicate, leading to cellular injury and inflammation. The immune response to the infection contributes to liver damage. Antiviral therapies aim to inhibit viral replication, either by directly targeting viral enzymes or by modulating the host immune response.

Pharmacodynamics

The pharmacodynamics of antiviral agents used in hepatitis treatment involve the inhibition of viral replication, reduction of viral load, and improvement of liver function. This can lead to a decrease in serum liver enzymes (ALT and AST) and an improvement in clinical symptoms. In chronic hepatitis B and C, sustained virologic response is the goal, indicating effective viral suppression.

Pharmacokinetics

The pharmacokinetics of antiviral medications used for hepatitis can vary significantly depending on the specific drug. Generally, these agents are absorbed from the gastrointestinal tract, metabolized in the liver, and excreted through urine or feces. The half-lives of these drugs can vary, influencing dosing schedules.

Pregnancy

Consult medical guidelines as hepatitis can pose risks during pregnancy; specific management depends on the type of hepatitis.

Breast-feeding

Consult healthcare providers, as the safety of certain hepatitis medications during breastfeeding varies.

Storage

Store in a cool, dry place away from direct sunlight; specific storage conditions may vary based on the medication used.

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

Indications

• Diabetes (insulin therapy)
• Cancer (monoclonal antibodies)
• Infectious diseases (vaccines)
• Hemophilia (clotting factors)
• Autoimmune disorders (biologics)

Dosage

Children: Dosage for pediatric patients is highly variable and should be determined based on the specific recombinant product and the child's clinical condition. Refer to specific guidelines or product information for dosing recommendations.

Adults: Dosage varies widely based on the specific recombinant product being used. Consult specific guidelines or product information for accurate dosing.

Mechanism of action

Recombinant DNA works by inserting a specific gene of interest into a plasmid or viral vector, which is then introduced into host cells. The host cells use their own cellular machinery to transcribe and translate the inserted gene into a protein. This process enables the production of therapeutic proteins that can mimic or replace faulty proteins in diseases, stimulate immune responses, or provide other therapeutic benefits.

Pharmacodynamics

The pharmacodynamics of recombinant products varies depending on the specific protein produced. Generally, they exert their effects by binding to specific receptors or enzymes in the body, modifying biological processes such as metabolism, immune response, or cell signaling. The therapeutic proteins produced can act as agonists or antagonists to modulate physiological responses.

Pharmacokinetics

The pharmacokinetics of recombinant proteins can be complex, as they depend on the specific product and its formulation. Factors such as absorption, distribution, metabolism, and excretion (ADME) can vary widely. Typically, these proteins may have a prolonged half-life due to modifications that protect them from proteolysis or enhance their distribution in tissues. The route of administration (e.g., subcutaneous, intravenous) also significantly affects their pharmacokinetic profiles.

Pregnancy

Data on the use of rdna in pregnancy is limited. The potential risks and benefits should be assessed on a case-by-case basis.

Breast-feeding

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

Storage

Store at room temperature, away from light and moisture. Specific storage conditions may vary based on formulation.

Indications

• Prevention of infectious diseases such as measles, mumps, rubella, hepatitis B, influenza, and human papillomavirus (HPV)
• Travel vaccinations for diseases endemic to certain regions
• Vaccination for at-risk populations, such as those with compromised immune systems or specific occupational exposures

Dosage

Children: Dosage varies by vaccine type and age; refer to the BNF for Children for specific dosing information.

Adults: Dosage varies by vaccine type and indication; refer to specific guidelines for each vaccine.

Mechanism of action

Vaccines work by mimicking an infection. They introduce a harmless component of a pathogen (antigen) to the immune system, prompting the body to produce an immune response. This includes the generation of antibodies and memory cells that provide long-term immunity. Upon subsequent exposure to the actual pathogen, the immune system is primed to respond more rapidly and effectively.

Pharmacodynamics

The pharmacodynamics of vaccines involves the activation of both humoral and cellular immunity. Vaccines stimulate B cells to produce antibodies against the pathogen, while T cells are activated to destroy infected cells. This dual response helps to establish immunological memory, which enables a faster and more robust response upon re-exposure to the pathogen.

Pharmacokinetics

Vaccines are administered via various routes, including intramuscular, subcutaneous, and oral. After administration, the antigens are presented to antigen-presenting cells, which activate T cells and stimulate B cell proliferation and differentiation. The half-life of vaccine-induced immunity varies depending on the type of vaccine, with some providing lifelong immunity and others requiring booster doses to maintain protection.

Contra-indications

• Severe allergic reaction (anaphylaxis) to a component of the vaccine
• Severe immunocompromised state for live attenuated vaccines

Adverse effects

• Local reactions at the injection site (pain, redness, swelling)
• Fever
• Fatigue
• Headache
• Muscle pain
• Joint pain
• Nausea

Interactions

• Immunosuppressive medications may reduce vaccine efficacy
• Concurrent administration of some vaccines may require spacing to optimize immune response

Precautions

• History of allergic reactions to vaccines or vaccine components
• Pregnancy (specific vaccines may be contraindicated)
• Moderate to severe acute illness with or without fever

Pregnancy

Consult healthcare provider. Some vaccines are contraindicated during pregnancy, while others are recommended.

Breast-feeding

Generally considered safe, but consult healthcare provider regarding specific vaccines.

Storage

Store in a refrigerator at 2-8°C. Do not freeze. Protect from light.

Formulations

• Liquid suspension for injection
• Lyophilized powder for reconstitution