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Zmax Dosage

Generic name: AZITHROMYCIN DIHYDRATE 2g in 60mL
Dosage form: powder, for oral suspension
Drug class: Macrolides

Medically reviewed by Last updated on Feb 24, 2023.


Zmax should be taken as a single 2 g dose. Zmax provides a full course of antibacterial therapy in a single oral dose. It is recommended that Zmax be taken on an empty stomach (at least 1 hr before or 2 hr following a meal).

Pediatric Patients

For pediatric patients 6 months and older, Zmax should be taken as a single dose of 60 mg/kg (equivalent to 27 mg/lb) body weight. The Zmax dose in mL is equivalent to the child's weight in lb (1 mL/lb dose, see Table 1 below), for a body weight of less than 75 lb (34 kg). It is recommended that Zmax be taken on an empty stomach (at least 1 hr before or 2 hrs following a meal).

Pediatric patients weighing 75 lb (34 kg) or more should receive the adult dose (2 g).

Table 1. Zmax Pediatric Dosage Guidelines: 1-dose regimen
Dosing Calculated on 1 mL/lb, Dose 1 mL of Suspension for every 1 lb of Body Weight for Children <75 lb (34 kg)*
Weight 1 mL/lb Dose
Lb Kg Dose Volume
(mg) (mL)
To ensure accurate dosing, a dosing spoon, medicine syringe, or cup is recommended.
10 5 270 10
15 7 405 15
20 9 540 20
25 11 675 25
30 14 810 30
35 16 945 35
40 18 1080 40
45 20 1215 45
50 23 1350 50
55 25 1485 55
60 27 1620 60
65 30 1755 65
70 32 1890 70
≥75 34 2000 Consume entire contents of bottle

Additional Treatment after Vomiting with Zmax

In the event that a patient vomits within 5 minutes of administration, the health care provider should consider additional antibiotic treatment since there would be minimal absorption of azithromycin. Since insufficient data exist on absorption of azithromycin if a patient vomits between 5 and 60 minutes following administration, alternative therapy should be considered. Neither a second dose of Zmax nor alternative treatment is warranted if vomiting occurs ≥60 minutes following administration, in patients with normal gastric emptying. In patients with delayed gastric emptying, alternative therapy should be considered.

Instructions for the Pharmacist

Constitute with 60 mL of water and replace cap. Shake bottle well before dispensing. Do not refrigerate. Constituted suspension should be consumed within 12 hr.

For pediatric dosing in patients weighing less than 75 lb (34 kg), use of a dosing device is recommended. The pharmacist should inform the patient's caregiver that any suspension remaining after dosing MUST be discarded.

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.