Dosage: Simple, Safe Steps to Take Your Meds Right

Getting the dose right matters more than you think. Too little and the drug may not work. Too much and you can cause harm. This page gives clear, practical rules you can use every time you pick up a pill or pour a liquid medicine.

Quick rules to follow

Always follow the label or your prescriber. If the label says "take one tablet twice daily," that means spacing doses about 12 hours apart for twice-daily drugs. For many common over-the-counter meds there are standard adult limits — for example, acetaminophen is commonly limited to about 3,000 mg per day in many guidelines, but check the product label and your doctor if you have liver problems. Want an example? Cetirizine (Zyrtec) is usually given as 10 mg once daily for adults, but children need a different dose by age or weight. When in doubt, ask the pharmacist.

Measuring and managing doses

Use the right tool. For liquid medicine, use the syringe or dosing cup that comes with the drug — kitchen teaspoons are not accurate. If concentration is listed (like 100 mg/5 mL), you can calculate how many milliliters you need: desired mg ÷ concentration mg per mL = mL to give. Write down the time you take each dose, especially when multiple medicines are involved.

Adjusting doses matters. Age, weight, kidney and liver function change how your body handles drugs. Kids and older adults often need lower doses. If you have kidney disease or take several medicines, your prescriber may lower the dose to avoid toxicity. Never change a prescription dose without talking to the prescriber first.

Watch for interactions. Some drugs boost or block others. Even common supplements can change drug levels. Ask a pharmacist whether your new med interacts with anything you already take. If you start feeling odd symptoms after a dose change — dizziness, severe nausea, new rashes, or heart palpitations — stop and call your provider.

Missed doses and stopping medicines. If you miss a dose, check the label: some meds say "take as soon as you remember," others say "skip if close to next dose." For many psychiatric drugs, antibiotics, or steroids, don’t stop suddenly; you may need a taper plan to avoid withdrawal or relapse. Your prescriber will advise if a taper is needed.

Keep three habits: read labels, measure carefully, and keep a medication list. Bring that list to every doctor visit. Our site has drug-specific articles (like Zyrtec, Protonix, norfloxacin) that go into exact dosing for those medicines — check the article for details and safety notes.

If you're unsure about any dose, call a pharmacist or your prescriber. Small questions now can prevent big problems later.