Can you split a losartan (angiotensin II receptor antagonist) and hydrochlorothiazide (HCTZ, diuretic) pill of 100/25 milligrams?

Can You Split a Losartan/Hydrochlorothiazide 100/25 mg Tablet?

No, you should not split a losartan/hydrochlorothiazide 100/25 mg tablet because the 100 mg losartan component is not scored, and splitting would compromise accurate dosing of both active ingredients in this fixed-dose combination.

Tablet Characteristics and Splitting Feasibility

• The losartan 100 mg tablet is described as "round, green film coated, biconvex, beveled-edge tablets; debossed with product identification '54 357' on one side and plain on the other side" with no score line 1
• Only the losartan 50 mg tablet has a score line ("scored on the other side"), which indicates manufacturer intent for potential splitting at that dose 1
• Film-coated tablets without score lines are not designed for splitting and may result in unequal distribution of active ingredients 1

Dosing Strategy for Dose Adjustment

If you need a lower dose than 100/25 mg, the appropriate approach is:

• Use the commercially available losartan 50 mg/hydrochlorothiazide 12.5 mg combination tablet instead of attempting to split the 100/25 mg tablet 2, 3
• The 50/12.5 mg combination is effective in 78.9% of patients with moderate-to-severe hypertension, achieving blood pressure control (sitting diastolic BP <90 mm Hg or ≥10 mm Hg reduction) 2
• This lower-dose combination produces additive antihypertensive effects with mean reductions of 17.2 mm Hg in systolic BP and 13.2 mm Hg in diastolic BP 3

Titration Algorithm

When managing hypertension with losartan/hydrochlorothiazide combinations 2, 4:

1. Start with losartan 50 mg/HCTZ 12.5 mg once daily for initial therapy
2. Reassess BP after 2-4 weeks of treatment
3. If BP goal not achieved (target <130/80 mm Hg for most patients per ACC/AHA guidelines 5), increase to losartan 100 mg/HCTZ 25 mg once daily
4. Monitor electrolytes (potassium, sodium) within 1-2 weeks after dose escalation, as higher HCTZ doses increase risk of hypokalemia and hyponatremia 5, 6

Safety Considerations for the 100/25 mg Dose

• The maximum dose of HCTZ (25 mg) should be used cautiously due to increased metabolic adverse effects without significant additional antihypertensive benefit beyond this dose 6
• Higher HCTZ doses (>25 mg) increase risk of hypokalemia, hyperuricemia, and glucose intolerance without proportional BP reduction 5, 6
• The 100/25 mg combination provides statistically significant additional BP reduction compared to 50/12.5 mg (mean difference -2.2 mm Hg diastolic, P=0.006), with 86.7% responder rate versus 78.9% 2

Common Pitfall to Avoid

Do not attempt to create intermediate doses by splitting unscored combination tablets. If BP control is inadequate on 50/12.5 mg but the full 100/25 mg dose causes adverse effects, add a third agent from a different class (calcium channel blocker or beta-blocker) rather than attempting to split tablets 5, 4.