Endocrine drugs Flashcards
levothyroxine uses
hypothyroidism (T4)
levothyroxine roa
oral or IV
levothyroxine ae
Overdosing can cause:
cardiac arrest, hypertension, palpitations. tachycardia, anxiety, heat intolerance, insomnia, hyperactivity, irritability, weight loss
liothyronine uses
hypothyroidism (T3)
liothyronine roa
oral/ IV
liothyronine ae
Overdosing can cause:
cardiac arrest, hypertension, palpitations. tachycardia, anxiety, heat intolerance, insomnia, hyperactivity, irritability, weight loss
levothyroxine monitoring and what time of day should it be taken
Levothyroxine monitoring:
When initiating L-T4 therapy, serum TSH should be measured to monitor for adequate replacement.
2. TSH should be measured 6-8 weeks after initiation of, or a change in L-T4 dose
What time of day:
Taken 30-45 minutes before breakfast on empty stomach.
thioamides examples
Carbimazole (1st line)
Propylthiouracil (PTU)
thioamides uses
- Graves disease
- Thyroid storm: PTU may be favoured because it has a small but additional effect of blocking the peripheral conversion of T4 to T3
thioamides moa
Inhibit thyroid peroxidase enzyme (TPO) and interfere with the iodination of thyroglobulin
- Propylthiouracil also inhibits deiodination of T4 to T3 systemically
- Carbimazole is converted to the active metabolite, thiamazole
thioamides roa
oral
thioamides ae
- Relatively low incidence of ADRs
- Most serious: Agranulocytosis
- If the patient develops a sore throat, fever, or
other signs or symptoms of infection, they should
stop and have a complete blood count
- If the patient develops a sore throat, fever, or
- The most common reaction is a mild, occasionally purpuric, urticarial papular rash
- Cholestatic jaundice with carbimazole
- Severe liver injury and acute liver failure with PTU
- therefore, carbimazole preferred for its less
hepatotoxicity
- therefore, carbimazole preferred for its less
strong iodine examples
Lugol’s Solution
Potassium Iodide
strong iodine uses
- Used in the preoperative period for thyroidectomy
- Useful in thyroid storm
strong iodine moa
- Suppress iodination of tyrosine
- Can be used to temporarily inhibit T4 and T3 synthesis and release, hence useful in thyroid storm
strong iodine ae
Allergic-like reactions can occur
radioactive iodine examples
131 Iodide
123 Iodide
radioactive iodine uses
graves disease
toxic nodular goitre
radioactive iodine roa
oral
radioactive iodine moa
- Radioactive iodine is rapidly and efficiently trapped by the thyroid sodium-iodide transporter, into the follicular cells, from which it is slowly liberated
radioactive iodine ae
- High incidence of delayed hypothyroidism
- Radioactive iodine therapy has been associated with worsening Graves’ ophthalmopathy
Biguanides examples
Metformin
Biguanides uses
First-line therapy for Type II DM
Biguanides moa
Decreases hepatic glucose production (gluconeogenesis)
Increases the density of insulin receptors at the tissues
Biguanides roa
oral
Biguanides ae
- GI issues - diarrhoea, vomiting, indigestion.
- Raise risk of Vit B12 malabsorption and hence Vit B12 deficiency
Thiazolidinediones examples
Pioglitazone
Thiazolidinediones uses
- High glucose-lowering efficacy
- Does not affect insulin secretion
Thiazolidinediones moa
Raise insulin-dependent glucose disposal and lower insulin resistance in liver
Thiazolidinediones roa
oral
Thiazolidinediones ae
- Weight gain
- Peripheral edema
- Increased risk of heart failure (fluid retention)
- Bone fractures
Sulfonylurea examples
Glipizide
Gliclazide
Glibenclamide