ZINNIA F

Indications

• Contraception
• Emergency contraception
• Menorrhagia management

Dosage

Children: For females of childbearing potential, the dosage for emergency contraception is the same as for adults, 1.5 mg as a single dose. For long-term contraception, consult the BNF

Adults: For emergency contraception, a single dose of 1.5 mg should be taken as soon as possible after unprotected intercourse, preferably within 12 hours but no later than 72 hours. For contraception, the recommended dose may vary based on the specific formulation and patient needs, refer to the BNF for specific guidelines.

Mechanism of action

Levonorgestrel suppresses gonadotropins, inhibiting ovulation by binding to progesterone and androgen receptors, and slowing the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus. This leads to the suppression of the luteinizing hormone (LH) surge necessary for ovulation. Additionally, it increases the thickness of cervical mucus, hindering sperm movement and survival, and induces changes in the endometrium that prevent implantation of a fertilized egg.

Pharmacodynamics

Levonorgestrel effectively prevents pregnancy through multiple mechanisms: by interfering with ovulation, fertilization, and implantation. The emergency contraceptive tablet is approximately 89% effective when taken within 72 hours after unprotected intercourse, while IUDs releasing levonorgestrel demonstrate over 99% effectiveness. It also serves a therapeutic role in preventing endometrial carcinoma associated with unopposed estrogen therapy.

Pharmacokinetics

Levonorgestrel is rapidly absorbed after oral administration, with peak plasma concentrations typically achieved within 1 to 2 hours. It has a half-life of approximately 24 hours and is metabolized in the liver. The drug is primarily excreted via urine and feces, and its pharmacokinetic profile can be affected by certain enzyme-inducing medications.

Contra-indications

• Pregnancy
• Severe liver disease
• Known or suspected hormone-sensitive malignancies
• Undiagnosed vaginal bleeding

Adverse effects

• Nausea
• Vomiting
• Fatigue
• Headache
• Dizziness
• Breast tenderness
• Mood changes
• Abdominal pain
• Changes in menstrual bleeding

Interactions

• Antiepileptics (carbamazepine, eslicarbazepine, fosphenytoin, oxcarbazepine, perampanel, phenobarbital, phenytoin, primidone, rufinamide, topiramate) may decrease efficacy
• Bosentan may decrease efficacy
• Ritonavir may decrease efficacy
• Lamotrigine may decrease effects
• Modafinil may decrease efficacy
• St. John's Wort may decrease efficacy
• Rifamycins may decrease efficacy
• Ulipristal may decrease efficacy

Precautions

• Monitor for ectopic pregnancy in women with a history of ectopic pregnancy or pelvic inflammatory disease
• Consider alternative contraceptive methods in cases of severe obesity
• Use caution in women with a history of thromboembolic disorders
• Regular follow-up is necessary to monitor for side effects and efficacy

Pregnancy

Levonorgestrel is contraindicated in pregnancy. It is not effective once implantation has occurred.

Breast-feeding

Levonorgestrel is excreted in breast milk, but it is considered safe for use during breastfeeding. However, it is advisable to take the medication just after breastfeeding to minimize exposure to the infant.

Storage

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

Formulations

• Levonorgestrel 1.5 mg oral tablet for emergency contraception
• Levonorgestrel intrauterine device (IUD) releasing 20 micrograms per day

Indications

• Iron deficiency anemia
• Prophylaxis of iron deficiency in at-risk populations
• Epithelial tissue changes such as atrophic glossitis and koilonychia

Dosage

Children: For children aged 1 month to 11 years: 0.25 mL per kilogram twice daily, with the total daily dose possibly given in 3 divided doses, not exceeding 20 mL per day. For children aged 12-17 years: 10 mL once daily.

Adults: The dose is calculated according to body weight and the iron deficit, specifying both the iron salt and formulation. For specific dosing, consult product literature.

Mechanism of action

Iron is necessary for the production of hemoglobin. Iron deficiency can lead to decreased production of hemoglobin and a microcytic, hypochromic anemia. Ferrous fumarate releases iron in the gastrointestinal tract, facilitating its absorption and subsequent incorporation into hemoglobin, thus alleviating anemia.

Pharmacodynamics

The major activity of supplemental iron, including ferrous fumarate, is in the prevention and treatment of iron deficiency anemia. Iron also has putative immune-enhancing, anticarcinogenic, and cognition-enhancing activities, supporting overall health and functionality.

Pharmacokinetics

Ferrous fumarate is absorbed in the gastrointestinal tract, with absorption being optimal in an acidic environment. The bioavailability can be influenced by dietary factors, such as the presence of certain foods or medications that may inhibit iron absorption. Once absorbed, iron is transported in the blood bound to transferrin and is stored in tissues as ferritin and hemosiderin. The elimination half-life of iron is variable and depends on the individual's iron status and the amount of iron stored.

Contra-indications

• Iron overload syndromes
• Repeated blood transfusions
• Porphyria cutanea tarda

Adverse effects

• Asthenia
• Drowsiness
• Urine discoloration
• Cold sweat
• Confusion
• Decreased level of consciousness
• Thrombophlebitis
• Headache
• Joint stiffness
• Pain in extremities
• Skin reactions
• Small intestinal bacterial overgrowth
• Thirst
• Nausea
• Constipation
• Diarrhea
• Decreased appetite

Interactions

• Iron absorption may be affected by antacids and certain medications that alter gastric pH.

Precautions

• Monitor iron status to avoid iron overload.
• Caution in patients with intestinal strictures or diverticular disease.
• Care in elderly patients and those on high doses.

Pregnancy

Iron is generally considered safe during pregnancy, but supplementation should be monitored to avoid overload.

Breast-feeding

Iron supplementation may be necessary for exclusively breast-fed infants if maternal iron stores are low.

Storage

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

Formulations

• Solution for injection (Iron as Iron sucrose 20 mg per 1 ml)
• Capsules containing iron formulations

Indications

• Hormonal contraception
• Menstrual cycle regulation
• Hormone replacement therapy
• Management of menopausal symptoms
• Treatment of polycystic ovary syndrome
• Endometriosis management
• Dysfunctional uterine bleeding

Dosage

Adults: The dosing of ethinylestradiol varies based on the formulation and indication. Commonly, it is administered in combination with progestins for contraception, typically as a daily oral tablet containing 20 to 35 micrograms of ethinyles

Mechanism of action

Ethinylestradiol acts as a synthetic estrogen by binding to estrogen receptors in estrogen-responsive tissues. It suppresses gonadotropic hormone secretion from the pituitary gland, leading to decreased luteinizing hormone levels. This results in reduced endometrial vascularization and prevents ovulation by inhibiting the hormonal changes necessary for ovarian follicle maturation. Additionally, it thickens cervical mucus to impede sperm movement and alters the endometrium to prevent implantation.

Pharmacodynamics

Ethinylestradiol has a long duration of action and a wide therapeutic index. It effectively decreases luteinizing hormone and gonadotropic hormone levels, thereby preventing ovulation and altering reproductive tract conditions. Patients using ethinylestradiol should be made aware of potential thrombotic risks, particularly in specific populations such as smokers and those with a history of thromboembolic disorders.

Pharmacokinetics

Ethinylestradiol is well absorbed when taken orally, with peak plasma concentrations occurring approximately 1 to 2 hours after administration. It has a high plasma protein binding rate, predominantly to sex hormone-binding globulin. The drug undergoes extensive hepatic metabolism, primarily by cytochrome P450 enzymes, and has a half-life of about 10-20 hours. Excretion is primarily via the kidneys, with metabolites being eliminated in urine.

Contra-indications

• Pregnancy
• History of thromboembolic disorders
• Active liver disease
• Severe hypertension
• Undiagnosed vaginal bleeding
• Hormone-sensitive cancers (e.g., breast cancer)
• Known hypersensitivity to ethinylestradiol or any component of the formulation

Adverse effects

• Nausea
• Headache
• Breast tenderness
• Mood changes
• Thromboembolic events (e.g., deep vein thrombosis, pulmonary embolism)
• Increased risk of certain cancers (e.g., breast and endometrial cancer)
• Hypertension
• Skin reactions (e.g., rash)

Interactions

• Antibiotics (e.g., rifampicin) may reduce effectiveness
• Anticonvulsants (e.g., phenytoin, carbamazepine) may reduce effectiveness
• St. John's Wort may reduce effectiveness
• Fostemsavir increases ethinylestradiol concentration
• Certain antiretrovirals may interact with ethinylestradiol

Precautions

• Monitor for signs of thromboembolism
• Caution in patients with a history of migraines
• Caution in patients with liver disease
• Regular breast examinations and mammograms are recommended
• Consider risks versus benefits in patients with a family history of breast cancer
• Use with caution in patients with hypertension, renal disease, asthma, epilepsy, and systemic lupus erythematosus

Pregnancy

Ethinylestradiol is contraindicated in pregnancy due to potential risks to the fetus and maternal health.

Breast-feeding

Caution is advised as ethinylestradiol may be excreted in breast milk. It is recommended to weigh the benefits of the treatment against potential risks to the nursing infant.

Storage

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

Formulations

• Tablets
• Transdermal patches
• Gels
• Sachets

Indications

• Iron-deficiency anemia (therapeutic)
• Iron-deficiency anemia (prophylactic)

Dosage

Children: For children aged 1 month to 11 years: 0.25 mL/kilogram twice daily. For children aged 12 to 17 years: 10 mL once daily.

Adults: 280 mg twice daily.

Mechanism of action

Ferrous sulfate acts as a source of iron, which is essential for the synthesis of hemoglobin, the protein in red blood cells that carries oxygen. Iron is absorbed in the intestines, where it is converted into a form that can be incorporated into hemoglobin. The mechanism involves transport proteins that facilitate iron uptake and incorporation into the heme group of hemoglobin.

Pharmacodynamics

The pharmacodynamic effect of ferrous sulfate is the increase in hemoglobin levels and improvement in symptoms of anemia, such as fatigue and weakness. Iron supplementation leads to increased erythropoiesis (red blood cell production) in the bone marrow, effectively correcting the deficit in iron stores and enhancing oxygen-carrying capacity.

Pharmacokinetics

Ferrous sulfate is absorbed in the gastrointestinal tract, particularly in the duodenum and proximal jejunum. The bioavailability of iron from ferrous sulfate can be affected by dietary factors, with enhanced absorption in acidic environments. Peak plasma concentrations typically occur within 2 to 6 hours post-administration. Iron is primarily stored in the liver and bone marrow, and any excess iron is excreted through feces, urine, and sweat.

Contra-indications

• Hypersensitivity to ferrous sulfate or any of its excipients
• Hemochromatosis
• Hemosiderosis
• Thalassemia
• Other anemias not due to iron deficiency

Adverse effects

• Gastrointestinal disturbances (nausea, constipation, diarrhea, abdominal pain)
• Dark stools
• Staining of teeth (with liquid formulations)
• Allergic reactions (rare)

Interactions

• Antacids may reduce the absorption of iron
• Tetracycline antibiotics may interfere with iron absorption
• Ascorbic acid (vitamin C) may enhance iron absorption
• Certain foods and beverages (e.g., tea, coffee, dairy) can decrease iron absorption

Precautions

• Use with caution in patients with peptic ulcer disease
• Monitor for signs of iron overload
• Assess the cause of anemia before initiation of therapy
• Keep out of reach of children to prevent accidental overdose

Pregnancy

Ferrous sulfate is generally considered safe for use during pregnancy to prevent or treat iron-deficiency anemia.

Breast-feeding

Ferrous sulfate is excreted in breast milk in small amounts but is considered safe for breastfeeding mothers.

Storage

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

Formulations

• Ferrous sulfate 200 mg tablets
• Ferrous sulfate 325 mg modified-release tablets
• Ferrous sulfate oral solution 140 mg/5 mL
• Ferrous sulfate drops

Indications

• Iron deficiency anemia
• Iron deficiency due to inadequate dietary intake
• Anemia associated with chronic disease
• Pregnancy-related anemia

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations based on age and weight.

Adults: Refer to the BNF for specific dosing recommendations, generally, adults may require 100-200 mg of elemental iron daily divided into several doses.

Mechanism of action

Ferrous ions (Fe2+) play a vital role in hemoglobin production by participating in the synthesis of heme, the iron-containing compound essential for oxygen transport in the blood. In addition, iron is a cofactor for various enzymes involved in metabolic pathways, including those related to DNA synthesis and energy production.

Pharmacodynamics

The pharmacodynamic effects of ferrous include increased hemoglobin synthesis, improved oxygen transport, and enhanced cellular energy metabolism. Supplementation leads to an increase in serum ferritin levels and replenishment of iron stores in the body, which is particularly beneficial in cases of iron deficiency anemia.

Pharmacokinetics

Ferrous iron is absorbed primarily in the duodenum and upper jejunum of the small intestine. The absorption rate can be influenced by various factors, including the presence of food, the form of iron, and individual patient characteristics. Once absorbed, ferrous is transported in the bloodstream bound to transferrin, and it is stored in the liver, spleen, and bone marrow as ferritin. The elimination half-life of iron is not well-defined as it is not excreted directly but rather recycled in the body.

Pregnancy

Not contraindicated, but iron supplementation should be done under medical supervision.

Breast-feeding

Iron is excreted in breast milk, but supplementation is generally considered safe.

Storage

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

Mechanism of action

Ethinylestradiol is a synthetic estrogenic compound. Use of estrogens have a number of effects on the body including reduced bone density. Combined oral contraceptives suppress ovulation by suppressing gonadotrophic hormone, thickening cervical mucus to prevent the travel of sperm, and preventing changes in the endometrium required for implantation of a fertilized egg. Ethinylestradiol decreases luteinizing hormone, decreasing vascularity in the endometrium. It also increases sex hormone binding globulin. Endogenous estrogens are largely responsible for the development and maintenance of the female reproductive system and secondary sexual characteristics. Although circulating estrogens exist in a dynamic equilibrium of metabolic interconversions, estradiol is the principal intracellular human estrogen and is substantially more potent than its metabolites estrone and estriol at the receptor level. ... After menopause, most endogenous estrogen is produced by conversion of androstenedione, secreted by the adrenal cortex, to estrone by peripheral tissues. Thus, estrone and the sulfate conjugated form, estrone sulfate, are the most abundant circulating estrogens in postmenopausal women. The pharmacologic effects of ethinyl estradiol are similar to those of endogenous estrogens. Estrogens act through binding to nuclear receptors in estrogen-responsive tissues. To date, two estrogen receptors have been identified. These vary in proportion from tissue to tissue. Circulating estrogens modulate the pituitary secretion of the gonadotropins, luteinizing hormone (LH) and follicle stimulating hormone (FSH) through a negative feedback mechanism. Estrogens act to reduce the elevated levels of these hormones seen in postmenopausal women. Estrogens have an important role in the reproductive, skeletal, cardiovascular, and central nervous systems in women, and act principally by regulating gene expression. Biologic response is initiated when estrogen binds to a ligand-binding domain of the estrogen receptor resulting in a conformational change that leads to gene transcription through specific estrogen response elements (ERE) of target gene promoters; subsequent activation or repression of the target gene is mediated through 2 distinct transactivation domains (ie, AF-1 and AF-2) of the receptor. The estrogen receptor also mediates gene transcription using different response elements (ie, AP-1) and other signal pathways. Recent advances in the molecular pharmacology of estrogen and estrogen receptors have resulted in the development of selective estrogen receptor modulators (eg, clomiphene, raloxifene, tamoxifen, toremifene), agents that bind and activate the estrogen receptor but that exhibit tissue-specific effects distinct from estrogen. Tissue-specific estrogen-agonist or -antagonist activity of these drugs appears to be related to structural differences in their estrogen receptor complex (eg, specifically the surface topography of AF-2 for raloxifene) compared with the estrogen (estradiol)-estrogen receptor complex. A second estrogen receptor also has been identified, and existence of at least 2 estrogen receptors (ER-alpha, ER-beta) may contribute to the tissue-specific activity of selective modulators. While the role of the estrogen receptor in bone, cardiovascular tissue, and the CNS continues to be studied, emerging evidence indicates that the mechanism of action of estrogen receptors in these tissues differs from the manner in which estrogen receptors function in reproductive tissue. /Estrogen General Statement/ Intracellular cytosol-binding proteins for estrogens have been identified in estrogen-responsive tissues including the female genital organs, breasts, pituitary, and hypothalamus. The estrogen-binding protein complex (ie, cytosol-binding protein and estrogen) distributes into the cell nucleus where it stimulates DNA, RNA, and protein synthesis. The presence of these receptor proteins is responsible for the palliative response to e

Pharmacodynamics

Ethinylestradiol is a synthetic estrogen that decreases luteinizing hormone to decrease endometrial vascularization, and decreases gonadotrophic hormone to prevent ovulation. It has a long duration of action as it is taken once daily, and a wide therapeutic index as overdoses are generally not associated with serious adverse effects. Patients should be counselled regarding the risks of thrombotic events.

Mechanism of action

Iron is necessary for the production of hemoglobin. Iron-deficiency can lead to decreased production of hemoglobin and a microcytic, hypochromic anemia.

Pharmacodynamics

The major activity of supplemental iron is in the prevention and treatment of iron deficiency anemia. Iron has putative immune-enhancing, anticarcinogenic and cognition-enhancing activities.

Mechanism of action

Iron is necessary for the production of hemoglobin. Iron-deficiency can lead to decreased production of hemoglobin and a microcytic, hypochromic anemia.

Pharmacodynamics

The major activity of supplemental iron is in the prevention and treatment of iron deficiency anemia. Iron has putative immune-enhancing, anticarcinogenic and cognition-enhancing activities.

Mechanism of action

**Mechanism of action on ovulation** Oral contraceptives containing levonorgestrel suppress gonadotropins, inhibiting ovulation. Specifically, levonorgestrel binds to progesterone and androgen receptors and slows the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus. This process results in the suppression of the normal physiological luteinizing hormone (LH) surge that precedes ovulation. It inhibits the rupture of follicles and viable egg release from the ovaries. Levonorgestrel has been proven to be more effective when administered before ovulation. **Mechanism of action in cervical mucus changes** Similar to other levonorgestrel-containing contraceptives, the intrauterine (IUD) forms of levonorgestrel likely prevent pregnancy by increasing the thickness of cervical mucus, interfering with the movement and survival of sperm, and inducing changes in the endometrium, where a fertilized ovum is usually implanted. Levonorgestrel is reported to alter the consistency of mucus in the cervix, which interferes with sperm migration into the uterus for fertilization. Levonorgestrel is not effective after implantation has occurred. Interestingly, recent evidence has refuted the commonly believed notion that levonorgestrel changes the consistency of cervical mucus when it is taken over a short-term period, as in emergency contraception. Over a long-term period, however, levonorgestrel has been proven to thicken cervical mucus. The exact mechanism of action of levonorgestrel is not completely understood and remains a topic of controversy and ongoing investigation. *Effects on implantation** The effects of levonorgestrel on endometrial receptivity are unclear, and the relevance of this mechanism to the therapeutic efficacy of levonorgestrel is contentious. Prescribing information for levonorgestrel IUDs state that they exert local morphological changes to the endometrium (e.g. stromal pseudodecidualization, glandular atrophy) that may play a role in their contraceptive activity. **Mechanism of action in hormone therapy** When combined with estrogens for the treatment of menopausal symptoms and prevention of osteoporosis, levonorgestrel serves to lower the carcinogenic risk of unopposed estrogen therapy via the inhibition of endometrial proliferation. Unregulated endometrial proliferation sometimes leads to endometrial cancer after estrogen use. Norgestrel (and more specifically the active stereoisomer levonorgestrel) binds to the progesterone and estrogen receptors within the female reproductive tract, the mammary gland, the hypothalamus, and the pituitary. Once bound to the receptor, progestins like levonorgestrel will slow the frequency of release of gonadotropin releasing hormone (GnRH) from the hypothalamus and blunt the pre-ovulatory LH (luteinizing hormone) surge. Loss of the LH surge inhibits ovulation and thereby prevents pregnancy. Combination oral contraceptives act by suppression of gonadotrophins. Although the primary mechanism of this action is inhibition of ovulation, other alterations include changes in the cer-vical mucus (which increase the difficulty of sperm entry into the uterus) and the endometrium (which may reduce the likelihood of implantation). Progestins enter target cells by passive diffusion and bind to cytosolic (soluble) receptors that are loosely bound in the nucleus. The steroid receptor complex initiates transcription, resulting in an increase in protein synthesis. /Progestins/ Progestins are capable of affecting serum concentrations of other hormones, particularly estrogen. Estrogenic effects are modified by the progestins, either by reducing the availability or stability of the hormone receptor complex or by turning off specific hormone-responsive genes by direct interaction with the progestin receptor in the nucleus. In addition, estrogen priming is necessary to increase progestin effects by upregulating the number of progestin receptors and/or increasing progesterone product

Pharmacodynamics

Levonorgestrel prevents pregnancy by interfering with ovulation, fertilization, and implantation. The levonorgestrel-only containing emergency contraceptive tablet is 89% effective if it is used according to prescribing information within 72 hours after intercourse. The intrauterine and implantable devices releasing levonorgestrel are more than 99% in preventing pregnancy. Levonorgestrel utilized as a component of hormonal therapy helps to prevent endometrial carcinoma associated with unopposed estrogen administration.