Question

A certain antihistamine is often prescribed for allergies. A typical dose for a 100-pound is 21 mg every six hours. Complete parts (a) and (b) below. Following this dosage, how many 13.7 mg chewable tablets would be taken in a week? This antihistamine also comes in a liquid form with a concentration of 13.7 mg/7 mL. Following the prescribed dosage, how much liquid antihistamine should a 100-pound person take in a week?

Answer 1

A 100-pound individual prescribed 21 mg of antihistamine every six hours would take approximately 43 chewable tablets of 13.7 mg each, or about 300 mL of liquid antihistamine with a concentration of 13.7 mg/7 mL, over the span of one week.

Step-by-step explanation:

For the prescribed dosage of 21 mg every six hours for a 100-pound individual, we need to determine how many 13.7 mg chewable tablets and how much liquid antihistamine would be taken in a week.

Tablets

First, let's calculate the total dosage required in a week:

4 doses per day (every 6 hours) × 7 days = 28 doses.

• 28 doses × 21 mg per dose = 588 mg needed in a week.

Next, we find out how many 13.7 mg tablets make up 588 mg:

588 mg ÷ 13.7 mg/tablet ≈ 42.92 tablets.

Since we cannot take a fraction of a tablet, the person would take 43 chewable tablets of the antihistamine in a week (rounded up).

Liquid

For the liquid form:

1. Determine the total liquid required to deliver 588 mg.
2. For every 13.7 mg of the drug, 7 mL of liquid is needed.
3. 588 mg needed ÷ 13.7 mg/mL = 42.92 mL of liquid antihistamine.
4. Since each dose is 21 mg, the liquid required per dose is (21 mg ÷ 13.7 mg/mL) × 7 mL = 10.7 mL approximately.
5. 10.7 mL per dose × 28 doses = 299.6 mL of liquid antihistamine needed in a week.

The person should take approximately 300 mL of the liquid antihistamine in a week (rounded up).