The Dentist's Drug and Prescription Guide. Mea A. Weinberg
the dose of clarithromycin (Biaxin) in mL for a 10‐year‐old child weighing 70 lb
| Step 1 Convert pounds to kg: | 70 lb × 1 kg/2.2 lb = 31.8 kg |
| Step 2 Calculate the dose in mg: | 31.8 kg × 15 mg/kg/day = 477 mg/day |
| Step 3 Divide the dose by the frequency: | 477 mg/day ÷ 2 (bid) = 238.5 mg/dose bid |
| Step 4 Convert the mg dose to mL: | 238.5 mg/dose ÷ 250 mg/5 mL = 4.77 mL q12h |
| Step 5 Convert mL into teaspoonfulsa | 4.77 mL ÷ 5 mL = 0.954 teaspoonful bid |
a Each teaspoonful is 5 mL.
Table 3.10 Pediatric dosage schedule
Source: Adapted from www.rxlist.com/biaxin‐drug.htm
| Weight (kg) | Weight (lb) | Dosage (q12h) (tablets) | 125 mg/5 mLa (suspension) | 250 mg/5 mL (suspension) |
| 9 | 20 | 67.5 mg q12h | 2.7 mL q12h | 1.35 mL q12h |
| 18 | 40 | 136 mg q12h | 5.4 mL q12h | 2.7 mL q12h |
| 25 | 55 | 187.5 mg q12h | 7.5 mL q12h | 3.75 mL q12h |
| 34 | 75 | 255 mg q12h | 10 mL q12h | 5 mL q12h |
a A teaspoonful is 5 mL.
This is an easy‐to‐follow table for prescribing clarithromycin to pediatric patients; the usual recommended dosage is 15 mg/kg/day divided q12h for 10 days.
Table 3.11 How the clarithromycin (Biaxin) prescription should be written
| Rx: clarithromycin oral suspension 250 mg/5 mL |
| Disp: 1 bottle (100 mL) |
| Sig: Take 1 teaspoonful orally twice a day for 7 days for dental infection |
3.2.4 Azithromycin
3.2.4.1 Oral Suspension (Table 3.12)
Dose required: 10 mg/kg/day q24h × 3 days.
How supplied: oral suspension comes in concentrations of 100 mg/5 mL, 200 mg/5 mL, 1 g powder packet.
1 Q. When should the 100 mg/5 mL suspension be prescribed?
2 A. The 100 mg/5 mL strength is prescribed for younger children weighing less than 44 lb (20 kg). Table 3.12 Calculating the dose of azithromycin oral suspension in mL for a 10‐year‐old child weighing 70 lb and how the prescription should be writtenStep 1 Convert pounds to kg:70 lb × 1 kg/2.2 lb = 31.8 kgStep 2 Calculate the dose in mg:31.8 kg × 10 mg/kg/day = 318 mg/dayStep 3 Divide the dose by the frequency:318 mg/day once a day = 318 mg/doseStep 4 Convert the mg dose to mL:318 mg/dose ÷ 200 mg/5 mL = 7.9 mL q24h Rx: azithromycin oral suspension 200 mg/5 mLDisp: 1 bottle (100 mL)Sig: Take 7.9 mL orally once a day for 3 days for dental infectionTable 3.13 Calculating the dose of azithromycin tablets in mg for a 10‐year‐old child weighing 70 lbStep 1 Convert pounds to kg:70 lb × 1 kg/2.2 lb = 31.8 kgStep 2 Calculate the dose in mg:31.8 kg × 10 mg/kg/day = 318 mg/dayStep 3 Divide the dose by the frequency:318 mg/day once a day = 318 mg/dose once a dayThe strengths of tablets are 250, 500, or 600 mg. Since the dose is 318 mg once a day, it is probably more precise to prescribe the oral suspension.Table 3.14 Calculating the dose of clindamycin oral solution in mL for a 10‐year‐old child weighing 70 lb and how the prescription should be writtenStep 1 Convert pounds to kg:70 lb × 1 kg/2.2 lb = 31.8 kgStep 2 Calculate the dose in mg:31.8 kg × 10 mg/kg/day = 318 mg/dayStep 3 Divide the dose by the frequency:318 mg/day ÷ 3 (tid) = 106 mg/dose q8hStep 4 Convert the mg dose to mL:106 mg/dose ÷ 75 mg/5 mL = 7 mL tidStep 5 Convert mL into teaspoonfulsa7 mL ÷ 5 mL = 1.4 teaspoonful Rx: Clindamycin oral solution 75 mg/5 mLDisp: 1 bottleSig: Take 1.4 teaspoonful orally three times a day for 7 days for dental infectiona Each teaspoonful is 5 mL.
3.2.4.2 Azithromycin Tablets (Table 3.13)
Dose required: 10 mg/kg/day q24h × 3 days.
How supplied: 250 mg, 500 mg, 600 mg tablets.
3.2.5 Clindamycin
3.2.5.1 Clindamycin Oral Solution (Table 3.14)
Dosage required: 10–30 mg/kg/day q6–8 h.
How supplied: oral solution 75 mg/5 mL (100 mL bottle).
3.2.5.2 Clindamycin Capsules (Table 3.15)
Dosage required: 10–30 mg/kg/day q6–8 h.
How supplied: 75, 150, 300 mg capsules.
Table 3.15 Calculating the dose of clindamycin capsules in mg for a 10‐year‐old child weighing 70 lb
| Step 1 Convert pounds to kg: | 70 lb × 1 kg/2.2 lb = 31.8 kg |
| Step 2 Calculate the dose in mg: | 31.8 kg × 10 mg/kg/day = 318 mg/day |
| Step 3 Divide the dose by the frequency: |
318 mg/day ÷ 4 (qid) = 80 mg/dose q6h
|