Chlorthalidone

About Chlorthalidone

Chlorthalidone makes the kidneys pass more salt and water, lowering blood pressure and reducing swelling. It treats high blood pressure, alone or with other medicines, and is added for fluid retention from heart failure, cirrhosis, kidney disease, or corticosteroid or estrogen treatment. It works like a thiazide diuretic, but its label notes a different chemical structure, and it lasts far longer: according to the labels, its effect continues for up to 72 hours, against about 6 to 12 hours for hydrochlorothiazide.

Frequent urination, dizziness, nausea and headache are common. It can lower potassium, sodium and magnesium and raise blood sugar, uric acid, cholesterol and calcium, so blood tests are checked; gout can flare, and low potassium is a particular concern with digoxin. It can increase sun sensitivity and may worsen lupus, and people with kidney disease, heart failure or dehydration are at particular risk of sudden kidney failure. It is not used if you cannot pass urine or are allergic to sulfonamide-derived drugs. There is no boxed warning.

For blood pressure, generic tablets usually start at 25 mg once a day, taken in the morning with food. Thalitone is a 15 mg brand tablet, formulated differently, and Hemiclor is a 12.5 mg brand tablet. Chlorthalidone also comes combined with atenolol and with azilsartan (Edarbyclor), which are separate products on their own prescriptions.

Taking Chlorthalidone

How to take it

Once a day, or every other day if prescribed, preferably in the morning with food. Keep taking it even if you feel well. It can make you dizzy when you stand up quickly, especially at first.

If you miss a dose

Take it as soon as you remember, unless the next dose is almost due; then skip the missed dose and continue as usual. Do not take a double dose.

Storage

At room temperature in the original container, tightly closed, protected from light and moisture (not in a bathroom), out of reach of children.

Interactions to know about

It reduces how the kidneys clear lithium, raising the risk of lithium toxicity, and it adds to other blood pressure medicines. Corticosteroids make low potassium more likely, which matters most with digoxin. Insulin needs may change. Your prescriber may advise a low-salt diet and potassium-rich foods such as bananas and orange juice.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Chlorthalidone differs from pharmacy to pharmacy

Generic chlorthalidone has many makers and costs pharmacies little, so a cash quote mostly reflects each pharmacy’s dispensing fee and markup. Over years of use those differences add up, and a ninety-day fill carries one fee instead of three.

Thalitone and Hemiclor are single-source brands priced as brands, and a pharmacy that rarely dispenses them may need to order them. Neither can be swapped for generic tablets without a new prescription.

Ways to pay less for Chlorthalidone without insurance

• If you are prescribed Thalitone or Hemiclor, ask the prescriber whether a generic tablet would suit you; the pharmacy cannot switch it on its own.
• Ask for a ninety-day supply once your dose is settled, and whether chlorthalidone is on the pharmacy’s flat-price generic list.
• If you also take atenolol, ask for quotes on the combination tablet and on the two separate generics.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Chlorthalidone

1. 1.Is this generic chlorthalidone, Thalitone or Hemiclor, at the strength intended?
2. 2.Should I take it every morning with breakfast?
3. 3.Do I need more potassium, and when are my blood tests due?
4. 4.Could it affect my gout, diabetes or lithium?
5. 5.Do I need extra sun protection?

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