Routine Medication and Lab Follow-up

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In Process

Author / Curator: Chris Steele, MD MPH MS

Faculty Advisor:

GUIDELINES:
The format of each page are recommended guidelines. They should be fluid as each topic will have a unique flow.

(1) Be concise.

(2) Be evidence-based. (Everything should have a reputable citation and resource)

(3) Be clinically relevant. (Avoid unnecessary discussion of pathophysiology and epidemiology if it does not help clinical decision-making).


Learning Objectives

  • Know when to schedule a follow-up appointment for a healthy patient.
  • Understand which medications should be monitored and what labs to order.
  • Learn common labs and screening that should be performed for common primary care diagnoses such as diabetes and HIV.

Top Teaching Points

  • Spironolactone should have a potassium monitored every 3 months given the complication of hyperkalemia.
  • Beta blockers can be titrated ~2 weeks in the primary care setting. Titrating sooner, especially in heart failure, can lead to bradycardia.

Background

The following section are recommendations for when a provider should schedule routine visits and at what frequency certain labs should be ordered to monitor patients with certain medications or health conditions.

Management

Scheduling an Annual Visit

For healthy individuals, the following can be a baseline to determine when patients should see their primary care provider. This schedule should not be followed for those with illnesses that need more frequent monitoring.

  • Age 18-20: Every year.
  • Age 21-49: Every 1-3 years.
  • Age 50+: Every year.

Scheduling Follow-up for Common Conditions

One of the most challenging aspects of primary care is scheduling an appropriate follow-up appointment for those who need either improved control or frequent monitoring of their diseases. The following table is a list of common conditions and recommendations as to when a PCP should have their patients follow up.

Disease What to Monitor Frequency
Diabetes Please see the Follow-up for Diabetes Section
  • 3 month follow: Diabetics who are on insulin and well controlled, patients are eligible to get a HgA1c.
  • 6 months: Diabetics who have HgA1c <7 and who are not on insulin or pre-diabetics can get HgA1c.
  • <1 week: Diabetic patients on insulin who have sugars >350 and who have had recent insulin adjustment to ensure that sugars better controlled.
Hypertension[1] Blood pressure (BP)
  • 3-month follow up: BP systolic of 140-159 for those under 60 or systolic of 150-159 for those 60 years or older and or diastolic of 90-99, one can recommend lifestyle modifications and/or medications.*
  • <2-week follow up: BPs systolic >160 or diastolic >100, or if there was failure of first attempt to fail lifestyle/medication adjustment for a 3 month window.

* Labs may need to be ordered before the 3-month visit depending on the hypertensive agent of choice and may need an earlier follow-up appointment.

Medications and Follow-Up Labs[2]

The following is a summary of recommendations for when to order labs for monitoring.

Medication Lab(s) or Vitals Frequency Complication/Reason to Monitor
Aldosterone Antagnoists[3] BMP
  • Check a BMP panel 1 week after starting then every 3 months afterwards
NB: Do not start or stop the medication if K is >5.5 mEq/L, or GFR is <30 ml/min. For men, this is usually a Cr of 2.5 mg/dL and women a Cr of 2.0 mg/dL.
Ace Inhibitors (ACE)

Angiotensin Receptor Blockers (ARB)

BMP (Cr and K)
  • Check a BMP 1 week after starting, then 1 month after starting. If K and cr is stable over 2 months, then twice yearly.
NB: Discontinue ACE/ARB if potassium .5.5 mEq/L and or serum cr increases 30% within the 1st two months of starting.
Beta Blockers[4] Vitals
  • Consider down titrating or holding if a patient's heart rate is lower than 50 beats per minute.
NB: Titrate beta blockers only every 2 weeks.
Digoxin Digoxin Level
  • Digoxin levels should be checked in 1 week after changing doses or suspected non-adherence or adjustment of a dose.
Digoxin level

Check 6-8 hrs after dose.

Heart failure- 0.5-1 ng/mL

Atrial fibrillation: 2 ng/mL

Ecreted. through the kidneys

Diuretics (Both loop and thiazide diuretics) BMP, Magnesium
  • Check a BMP and magnesium level a week after starting therapy.
  • Consider BMP every 1-3 months for loop diuretics and at least ~6 months for thiazide diuretics.
  • K monthly until K is stable then every 3-6 months after.
Patients may need potassium supplementation.
Lithium TSH

Li Level

BMP,

CBC

  • All patients should get a baseline CBC, BMP and TSH. Women should get a pregnancy test.
  • Yearly BMP and TSH.
  • Lithium levels twice weekly until stable, then every 2 months.
NB: Lithium is renally excreted so kidney function should be monitored.

Normal Li trough 0.6-1.2 mEg/L.

Should be a taken 8-12 hrs after dose.

Metformin BMP; CBC
  • Baseline CBC and cr then annually afterwards.
NB: Metformin can cause megablastic anemia. It is contraindicated in CKD stage 3a or GFR less than 60 ml/min or more simplistically, with women who have serum cr >1.4 mg/dL and men with serum cr >1.5 mg/dl.
Niacin CMP, Uric Acid, Glucose
  • LFTs every 3 months for a year then every 6 months if stable.
  • Uric acid every 3 months for a year then annually when stable.
NB: If muscle symptoms, obtain potassium, creatine kinase (CK) and liver function testing (LFTs) to look for myositis.

Niacin can worsen hypophosphatemia, can increase serum uric acid levels and fasting glucose levels.

NSAID Class BMP
  • Varies and no set guidelines. may need to check weekly to monthly in high risk patients that could develop kidney injury.
NB: Patients with high risk of NSAID induced kidney injury are those over the age of 60, liver failure, heart failure patients, concurrent diuretic or ACE/ARB use, CDK Stage

or worse.

Retinoids Lipids

Glucose

LFTs

  • Make sure the following three labs are stable and check for 1 month with appropriate stability is achieved.
NB: Retinoid medications cause worsening diabetes.
Statins Lipid Panel
  • All asymptomatic patients with 1 or more cardiovascular risk factor and a 10-year ASCVD risk greater than 10% should be on statin therapy.
  • Recheck 6-8 weeks after starting therapy to see appropriate decline.
  • Lipid panel should be ordered by age 35 for men and 45 for women with no risk factors, or age 20 or older if they have 1 or more cardiovascular risk factor.
NB: If muscle symptoms, obtain K, creatinine kinase (CK) and LFTs to look for myositis.

These guidelines are adjusted for patients with heart disease and diabetes who have lower LDL goals.

Synthroid (Thyroid replacement) TSH reflux T4/T3
  • After starting or dose adjustment, adjust every 6-8 weeks.
  • Yearly after TSH at baseline.
  • Age 50 /w cardiac disease should get monitoring every 4-6 weeks.
NBInitial dose of Synthroid: 1.6 mcg/kg/day unless patient unless A) Age >50 (should start with 25-50 mcg/kg/day dose) or B) Age >50 with heart disease (should stat with 12.5/25 mcg/kg/day dose)

Subclinical hypothyroidism- 1 mcg/kg/day

Warfarin INR/PT
  • Daily when becoming therapeutic
  • Weekly to monthly when stable.
NB: Warfarin is metabolized by the cytochrome (CYP) P450 drug and new medications should be added cautiously.

Patients on warfarin should be part of a Coumadin clinic for adjustment and monitoring.

BMP = Basic Metabolic Panel; CBC=Complete Blood Count; CMP = Complete Metabolic Panel; Cr= Creatinine; INR/PT= International Normalization Ratio and Prothrombin Time; LFTs= Liver Functino Tests; K = Potassium; TSH = Thyroid Stimulating Hormine

Follow-up Labs for Diabetes Patients

Lab or Exam Frequency
HgA1c
  • Every 3 months if HgA1c >7
  • Every 6 months if HgA1c <7
Point of Care Glucose Every visit or if well controlled, based on the providers opinion.
Lipid Panel Yearly in stable patients and more frequently if not at clinical goal.
Kidney Function (GFR) Yearly creatinine check unless there is underline kidney disease or therapy that shortens the intervals (e.g. ACE inhibitors)
Microalbumin or spot protein creatinine ratio Yearly unless disease present and interval needs to be adjusted.
Blood Pressures Every visit
Foot exam Every 3-6 months
Eye exam Yearly

Follow-up Labs for HIV Patients

The following is an adaptation of the AIDSinfo Guidelines recommended by the Department of Healt and Human Service for monitoring patients with HIV. Please read the HIV page for more information on treating patients with HIV in the primary care setting.[5]

Lab Test Start of Care Start ART Therapy 3 to 6 Months 6 Months Year Other
HIV Testing x
CD4 Count x Yes, and repeat 2 months after starting therapy
  • First 2 years of ART
  • CD4 count less than 300 cell/mm3
After 2 years of therapy with consistently suppressed VL one can adjust to
    • CD4 300-500: Yearly
    • CD4 >500+= Optional
Always recheck if ART is switched, there has been non-adherence or clinical assessment suggests failure of treatment.
HIV Viral Load
  • Repeat every 2 months until VL less than 200 copies. Then move to 3-6 months.
  • 6 month intervals should be extended to those with stable CD4 counts showing 2 years adherence.
Resistance Testing
  • Recommend checking if A) Medication non-adherence; B) If VL and CD4 count change in a way suggestive of resistance C) If felt that resistance is possible given clinical assessment.
Abacavir HLA-B57-01 Screen
CCR5 Antagnoist Tropism Testing
Hepatitis B Screening Complete if not done on screen Repeat if received immunity to confirm antibody formation.
Hepatitis C Screening x Complete if not done on screen
Complete Metabolic Panel (Cr, K, Na, Bicarb and Glucose, AST, ALT, Alk Phos) x x x
  • Monitoring should be adjusted for those with CKD with close follow-up with a nephrologist.
  • LFT rises are seen with NRT, some protease inhibitors and atazanavir (increased bilirubin in blood)
Phosphorus x x x
  • Should be done for people on TAF/TDF (Tenofovir) regiments
Diabetes Screening (HgA1c and glucose) x If patient has diabetes If patient has pre-diabetes
  • Those with diabetes should receive a HgA1c every 3 months, those with pre-diabetes should be screened every 6-12 months.
  • POC glucose can be obtained every visit.
Urinalysis Check for TAF/TDF regiments (Tenofovir)
CBC x x Check for Zidovudine watching for neutropenia and anemia

x = lab should be obtained.

*Patients at greatest risk for increased cr or K from ace/arbs are those with diabetes, on NSAIDs or immunosuppressive therapies, diuretics, renal artery stenosis or GFR less than 60 mL/min.

Other Teaching Pearls

Trial Summaries

Ongoing controversies / New updates

What's the latest scuttlebutt? This is a place to include new guidelines, controversies, or other recent updates on the topic.

Teaching Resources

References

  1. https://dph.georgia.gov/sites/dph.georgia.gov/files/related_files/site_page/Hypertension%20Action%20Guide%20for%20Health%20Care%20Providers.pdf
  2. http://www.mysccg.com/generalDocuments/Lab%20Work%20Pharmacist%20Letter.pdf
  3. Hunt SA, Abraham WT, Chin MH, et al. 2009 focused update incorporated into the ACC/AHA 2005 guidelines for the diagnosis and management of chronic heart failure in adults: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines developed in collaboration with the International Society for Heart and Lung Transplantation. J Am Coll Cardiol 2009;53:e1-e90. 
  4. https://www.ncbi.nlm.nih.gov/pubmed/12647475
  5. https://aidsinfo.nih.gov/guidelines/html/1/adult-and-adolescent-arv/3/tests-for-initial-assessment-and-follow-up

Contributors

Alexey, Christopher Steele