Endocrine Flashcards
Instances to discontinue Metformin
- Use of contrast medium (until 48 hours post)
- eGFR < 30 mL/min/1.73m2
Stress states:
- Heart failure (esp ADHF)
- Severe liver impairment
- Alcoholism
- Sepsis
Dosage of metformin according to renal clearance
eGFR >45: Max 850 mg TDS
eGFR 30-45: Max 500 mg BD. No new initiation
eGFR <30: Avoid
Thiazolidinediones drug interactions
Pioglitazone: 3A4 substrate
Rosiglitazone: 2C9 substrate
Cautions for thiazolidinediones
- Edema and HF exacerbation
- Bladder cancer (pioglitazone)
- Fracture risk
- Hepatotoxicity and LFT derangements
Cautions for DPP4 inhibitors
- Pancreatitis (sitagliptin)
- Arthralgias
- Heart failure (saxagliptin)
- SJS/TEN
- Not to be used with GLP-1 agonists
DPP4 inhibitor that does not require renal dose adjustment
Linagliptin (5 mg OD)
SGLT2 inhibitors with FDA approval for ASCVD benefit
Canagliflozin (CANVAS)
Empagliflozin (EMPA-REG)
SGLT2 inhibitors with FDA approval for HF benefit
Dapagliflozin (DAPA-HF / DELIVER)
Empagliflozin (EMPEROR-Reduced / Preserved)
SGLT2 inhibitors renal dosing adjustment
Reduced glucose lowering effect when eGFR <45
Dapagliflozin: <25 not initiated, continue at 10 mg OD
Empagliflozin: <30 10 mg OD; <20 unclear benefit
Dose of evidence-based GLP-1 agonists
Dulaglutide: SC 0.75-1.5 mg once weekly, up to 3-4.5 mg once weekly
Liraglutide: SC 0.6 mg OD, up to 1.8 mg OD
Semaglutide: SC 0.25 mg once weekly, up to 1 mg once weekly
Goal for HbA1c
Stringent: <6.5% (AACE), <7% (ADA)
Lenient: 8%
Drugs interacting with Metformin
Cimetidine
Digoxin
Dolutegravir
Ranolazine (not to exceed 850 mg BD if ranolazine is used at 1000 mg BD)
Iodine contrast medium (hold for at least 48 hours after)
Concerns for SGLT2 inhibitors
- AKI
- DKA
- Fournier’s gangrene
- High stress states
Concerns for GLP-1 agonists
- Pancreatitis
- Thyroid C cell tumors
- Gastroparesis
Insulins that should not be mixed together
- Glargine + all other insulins (pH issue)
- Glulisine + all other insulins except NPH
- Detemir + all other insulins
Cut-off for over-basalisation of insulin
> 0.5 IU/kg/day
Administration of levothyroxine
On empty stomach 30-60 mins before food. Or 4 hours after last meal at night
Monitoring of levothyroxine treatment
TSH (IN 4-8 weeks, target 0.4-5 mIU/L)
Free T4 (if central hypothyroidism)
ADR of thionamides
- Abnormal tastes
- Rash
- Agranulocytosis
- Carbimazole: pancreatitis, teratogenicity
- PTU: hepatotoxicity, autoimmune vasculitis
Interaction of thionamides
RAI with NaI (to be stopped at least 3 days before RAI)
Treatment of subclinical hypothyroidism
- TSH >10 or
- TSH 4.5-10 AND symptomatic/TPO-antibody present/history of CVD
Monitoring with thionamide treatment
Free T4
Total T3
Monitor at 4-6 weeks interval and titrate doses at monthly intervals
Treatment of subclinical hyperthyroidism
TSH <0.1
Use BB if AF develops
Risks associated with alpha antagonists
- Flu-like symptoms, nasal congestion
- Orthostasis
- Intraoperative floppy iris syndrome
- Retrograde ejaculation
