Endo Avoid Sympathomimetic Htn

---
name: endo-avoid-sympathomimetic-htn
description: Recommends against using sympathomimetic agents (phentermine, diethylpropion) in patients with uncontrolled hypertension or a history of heart disease. Triggers include clinician questions such as “Is it safe to prescribe phentermine for this patient with uncontrolled hypertension?” or “Should I avoid sympathomimetics in a patient with prior MI seeking weight‑loss medication?”.
---

# Avoid sympathomimetics in uncontrolled hypertension/heart disease

## STEP 1 — Gather Information
- Measure current blood pressure (SBP/DBP) and assess hypertension control status.
- Obtain history of heart disease: prior MI, angina, heart failure, significant arrhythmia, or revascularization.
- Review current medications for contraindications (MAOIs, other sympathomimetics) and assess pregnancy, glaucoma, hyperthyroidism, substance use.

## STEP 2 — Rule In / Rule Out
- **Rule in contraindication** if: (a) SBP ≥140 mm Hg or DBP ≥90 mm Hg despite treatment **OR** (b) documented history of heart disease (MI, CHF, significant arrhythmia).  
- **Rule out** if blood pressure is at goal (<140/90) and no cardiac history; then sympathomimetics may be considered per other guidelines.

## STEP 3 — Classify or Stratify
- **Uncontrolled hypertension** (BP ≥140/90) → high risk for sympathomimetic‑induced BP rise.  
- **Controlled hypertension** (BP <140/90) → lower risk, but still exercise caution.  
- **History of heart disease** → independent contraindication regardless of BP.

## STEP 4 — Decide
- If contraindication ruled in, **avoid phentermine and diethylpropion**.  
- Select alternative weight‑loss agents with lower cardiovascular risk (e.g., orlistat, lorcaserin, or phentermine/topiramate only after cardiology clearance).  
- Document decision and discuss lifestyle modification as first‑line.

## Clinical Guardrails / Mimics / Pitfalls
- Do not rely on self‑reported “normal” BP; use office‑measured values.  
- Beware of masked hypertension; consider ambulatory monitoring if borderline.  
- Avoid in patients with tachycardia, arrhythmia, or uncontrolled hyperthyroidism.  
- Do not combine with MAOIs or other stimulants due to hypertensive crisis risk.  
- Monitor BP and heart rate after initiation if any weight‑loss drug is used.

## Concrete Clinical Example
A 58‑year‑old man with BMI 32 kg/m² presents for weight‑loss counseling. His office BP is 152/94 mm Hg on lisinopril and hydrochlorothiazide, and he reports a prior MI 2 years ago. He asks whether phentermine is safe. Following the algorithm, uncontrolled hypertension and history of heart disease trigger the contraindication; phentermine is avoided and orlistat is prescribed instead, with monthly BP checks.

**Source:** Pharmacological Management of Obesity: An Endocrine Society Clinical Practice Guideline, Apovian et al., 2015, DOI:10.1210/jc.2014-3415