Chlorothiazide Sodium and Colistimethate

• Generic Name: chlorothiazide
• Dosage Forms: n.a.
• Other Brand Names: Diuril, Diuril Sodium

Used alone or in combination with other antihypertensive agents for all stages of hypertension.

Thiazide diuretics are recommended as one of several preferred agents for the initial management of hypertension according to current evidence-based guidelines; other preferred options include ACE inhibitors, angiotensin II receptor antagonists, and calcium-channel blockers. While there may be individual differences with respect to recommendations for initial drug selection and use in specific patient populations, current evidence indicates that these antihypertensive drug classes all generally produce comparable effects on overall mortality and cardiovascular, cerebrovascular, and renal outcomes.

Individualize choice of therapy; consider patient characteristics (e.g., age, ethnicity/race, comorbidities, cardiovascular risk) as well as drug-related factors (e.g., ease of administration, availability, adverse effects, cost).

A 2017 ACC/AHA multidisciplinary hypertension guideline classifies BP in adults into 4 categories: normal, elevated, stage 1 hypertension, and stage 2 hypertension.

Source: Whelton PK, Carey RM, Aronow WS et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2018;71:e13-115.

Individuals with SBP and DBP in 2 different categories (e.g., elevated SBP and normal DBP) should be designated as being in the higher BP category (i.e., elevated BP).

The goal of hypertension management and prevention is to achieve and maintain optimal control of BP. However, the BP thresholds used to define hypertension, the optimum BP threshold at which to initiate antihypertensive drug therapy, and the ideal target BP values remain controversial.

The 2017 ACC/AHA hypertension guideline generally recommends a target BP goal (i.e., BPs to achieve with drug therapy and/or nonpharmacologic intervention) of <130/80 mm Hg in all adults regardless of comorbidities or level of atherosclerotic cardiovascular disease (ASCVD) risk. In addition, an SBP goal of <130 mm Hg generally is recommended for noninstitutionalized ambulatory patients ≥65 years of age with an average SBP of ≥130 mm Hg. These BP goals are based upon clinical studies demonstrating continuing reduction of cardiovascular risk at progressively lower levels of SBP.

Other hypertension guidelines generally have based target BP goals on age and comorbidities. Guidelines such as those issued by the JNC 8 expert panel generally have targeted a BP goal of <140/90 mm Hg regardless of cardiovascular risk and have used higher BP thresholds and target BPs in elderly patients compared with those recommended by the 2017 ACC/AHA hypertension guideline.

Some clinicians continue to support previous target BPs recommended by JNC 8 due to concerns about the lack of generalizability of data from some clinical trials (e.g., SPRINT study) used to support the 2017 ACC/AHA hypertension guideline and potential harms (e.g., adverse drug effects, costs of therapy) versus benefits of BP lowering in patients at lower risk of cardiovascular disease.

Consider potential benefits of hypertension management and drug cost, adverse effects, and risks associated with the use of multiple antihypertensive drugs when deciding a patient's BP treatment goal.

For decisions regarding when to initiate drug therapy (BP threshold), the 2017 ACC/AHA hypertension guideline incorporates underlying cardiovascular risk factors. ASCVD risk assessment recommended by ACC/AHA for all adults with hypertension.

ACC/AHA currently recommend initiation of antihypertensive drug therapy in addition to lifestyle/behavioral modifications at an SBP ≥140 mm Hg or DBP ≥90 mm Hg in adults who have no history of cardiovascular disease (i.e., primary prevention) and a low ASCVD risk (10-year risk <10%).

For secondary prevention in adults with known cardiovascular disease or for primary prevention in those at higher risk for ASCVD (10-year risk ≥10%), ACC/AHA recommend initiation of antihypertensive drug therapy at an average SBP ≥130 mm Hg or an average DBP ≥80 mm Hg.

Adults with hypertension and diabetes mellitus, chronic kidney disease (CKD), or age ≥65 years are assumed to be at high risk for cardiovascular disease; ACC/AHA state that such patients should have antihypertensive drug therapy initiated at a BP ≥130/80 mm Hg. Individualize drug therapy in patients with hypertension and underlying cardiovascular or other risk factors.

In stage 1 hypertension, experts state that it is reasonable to initiate drug therapy using the stepped-care approach in which one drug is initiated and titrated and other drugs are added sequentially to achieve the target BP. Initiation of antihypertensive therapy with 2 first-line agents from different pharmacologic classes recommended in adults with stage 2 hypertension and average BP >20/10 mm Hg above BP goal.

Black hypertensive patients generally tend to respond better to monotherapy with thiazide diuretics or calcium-channel blockers than to other antihypertensive drug classes (e.g., ACE inhibitors, angiotensin II receptor antagonists). However, the combination of an ACE inhibitor or an angiotensin II receptor antagonist with a calcium channel blocker or thiazide diuretic produces similar BP lowering in black patients as in other racial groups.

Thiazides may be preferred in hypertensive patients with osteoporosis. Secondary beneficial effect in hypertensive geriatric patients of reducing the risk of osteoporosis due to effect on calcium homeostasis and bone mineralization.

Edema (General)

Management of edema resulting from various causes; diagnose etiology before use.

Edema caused by renal disease or by corticosteroids or estrogens may be relatively resistant to treatment.

Ineffective in patients with Scr or BUN concentrations greater than twice normal.

May be ineffective in patients with GFR <15–25 mL/minute; even when GFR is 25–50 mL/minute, more potent (e.g., loop) diuretics may be indicated.

No substantial difference in clinical effects or toxicity of comparable thiazide or thiazide-like diuretics except metolazone may be more effective in edema with renal impairment.

Edema in Heart Failure

Management of edema associated with heart failure.

Most experts state that all patients with symptomatic heart failure who have evidence for, or history of, fluid retention generally should receive diuretic therapy in conjunction with moderate sodium restriction, an agent to inhibit the renin-angiotensin-aldosterone (RAA) system (e.g., ACE inhibitor, angiotensin II receptor antagonist, angiotensin receptor-neprilysin inhibitor [ARNI]), a β-adrenergic blocking agent (β-blocker), and in selected patients, an aldosterone antagonist.

Loop diuretics (e.g., bumetanide, ethacrynic acid, furosemide, torsemide) are diuretics of choice for most patients with heart failure.

Do not use diuretics as monotherapy in heart failure even if symptoms (e.g., peripheral edema, pulmonary congestion) are well controlled; diuretics alone do not prevent progression of heart failure.

Diuretics produce rapid symptomatic benefits, relieving pulmonary and peripheral edema more rapidly (within hours or days) than cardiac glycosides, ACE inhibitors, or β-blockers (in weeks or months).

Diuretics should be continued in heart failure and comorbid conditions (e.g., hypertension) where ongoing therapy with the drugs are indicated.

Edema Secondary to Nephrotic Syndrome

May be useful if the patient fails to respond to corticosteroid therapy.

More likely to become refractory to thiazides than edema associated with congestive heart failure, and more potent diuretics may be required.

Edema in Pregnancy

Generally responds well to thiazides except when caused by renal disease.

Thiazides should not be used for routine therapy in pregnant women with mild edema who are otherwise healthy.

• Generic Name: colistimethate
• Dosage Forms: n.a.
• Other Brand Names: Coly Mycin M

Colistimethate is an antibiotic that fights bacteria.

Colistimethate is used to treat infections caused by bacteria.

Colistimethate may also be used for purposes not listed in this medication guide.