PTCE · Medications · 7 min read
Anti-Infective Drugs
- Identify major anti-infective drug classes, their naming conventions, primary mechanisms of action, and common brand and generic names.
- Recognize key safety considerations, auxiliary labeling needs, storage guidelines, and preparation procedures for common antibacterial, antiviral, and antifungal medications.
- Distinguish the technical duties of the pharmacy technician during anti-infective dispensing from clinical tasks that require pharmacist intervention, review, and patient counseling.
Beta-Lactam Antibiotics: Penicillins and Cephalosporins
Penicillins are beta-lactam antibiotics that work by inhibiting bacterial cell wall synthesis. Common medications in this class include amoxicillin, ampicillin, and penicillin V potassium. To overcome bacterial resistance, amoxicillin is frequently combined with clavulanate potassium and sold under the brand name Augmentin. In this combination, clavulanate inhibits certain bacterial beta-lactamases, helping protect amoxicillin from inactivation; the combination does not overcome every form of bacterial resistance.
Cephalosporins are another essential family of beta-lactam antibiotics. Generic cephalosporin names typically begin with the prefix 'cef-' or 'ceph-'. Cephalexin is a widely used first-generation cephalosporin known by the brand name Keflex. Cefdinir is an oral third-generation cephalosporin that carries a distinctive characteristic: it can cause reddish stool discoloration when taken alongside iron supplements. Another third-generation agent is ceftriaxone, an injectable cephalosporin commonly reconstituted for intramuscular or intravenous administration in institutional and outpatient settings.
Because penicillins and cephalosporins share related beta-lactam structures, patients with a documented penicillin allergy may also react to certain cephalosporins. This allergic cross-reactivity is particularly relevant for cephalosporins that possess similar side chains. When an allergy alert appears at order entry, the technician must never override or bypass it; technicians must flag penicillin allergy alerts so the supervising pharmacist can clinically evaluate the risk prior to dispensing.
Oral liquid forms of these antibiotics demand precise handling and clear communication regarding shelf life. Amoxicillin oral suspension is stable either refrigerated or kept at room temperature and is typically discarded after 14 days. By contrast, reconstituted Augmentin oral suspension must be refrigerated and must be discarded after 10 days. Technicians must verify these storage parameters and clearly mark beyond-use dates on the prescription container.
| Medication Name | Active Component(s) | Required Storage Condition | Discard Timeframe (Beyond-Use Date) |
|---|---|---|---|
| Amoxicillin Oral Suspension | Amoxicillin | Refrigerated or room temperature | Discard after 14 days |
| Augmentin Oral Suspension | Amoxicillin combined with clavulanate potassium | Refrigerate only | Discard after 10 days |
Common mistakes
- Assuming all reconstituted antibiotic suspensions share the same storage requirements; for example, confusing amoxicillin (stable refrigerated or at room temperature for 14 days) with Augmentin (must be refrigerated and discarded after 10 days).
- Failing to flag a penicillin allergy alert when filling a cephalosporin prescription, assuming the pharmacist will notice it without the technician highlighting the system alert.
- Using tap water instead of the manufacturer-specified water type when reconstituting oral antibiotic powders under pharmacist supervision.
- Attempting to counsel patients on missed doses, fluid intake, or drug interactions instead of referring these clinical inquiries directly to the pharmacist.
Key points
- Penicillins and cephalosporins are cell-wall inhibitors; technicians must flag penicillin allergy alerts for the pharmacist when dispensing cephalosporins due to potential cross-reactivity.
- Augmentin combines amoxicillin with clavulanic acid (a beta-lactamase inhibitor) and must be refrigerated and discarded after 10 days, while amoxicillin suspension can be kept at room temperature or refrigerated for 14 days.
- Macrolides bind the 50S ribosomal subunit and can cause CYP3A4 drug interactions, whereas tetracyclines bind the 30S subunit, are generally avoided in pregnancy and children under eight, and carry photosensitivity and esophageal irritation risks.
- Fluoroquinolones carry a black-box warning for tendinitis and tendon rupture and bind multivalent cations, while sulfamethoxazole/trimethoprim inhibits folic acid synthesis and requires sulfa allergy screening.
- Antivirals include oseltamivir (most effective within 48 hours for influenza) and acyclovir/valacyclovir, while antifungals include azoles (inhibiting ergosterol synthesis), nystatin, and oral terbinafine (requiring liver enzyme monitoring).
- Technicians reconstitute oral powders using specified water under pharmacist supervision, apply required auxiliary labels like 'Shake Well Before Use', and refer all clinical alerts, counseling, and final verifications to the pharmacist.
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Sample lesson: Generic and Brand Names, Indications and OTC Products25 practice questions on this exam
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