1.3 Anti-Infective and Analgesic Medications
Key Takeaways
Penicillin allergies affect about 10% of patients; cross-reactivity with cephalosporins is approximately 1-2%.
Fluoroquinolones have a black box warning for tendon rupture and should be avoided in children when possible.
Opioid analgesics are Schedule II controlled substances requiring special handling and DEA compliance.
NSAIDs can cause GI bleeding, kidney damage, and cardiovascular events; avoid in patients with kidney disease.
Acetaminophen maximum daily dose is 3-4 grams; hepatotoxicity risk increases with alcohol use.
Anti-infective and analgesic medications are among the most commonly dispensed drugs. Pharmacy technicians must understand their classifications, uses, and safety considerations.
Antibiotic Classifications
Penicillins (-cillin)
| Generic Name | Brand Name | Spectrum | Key Points |
|---|---|---|---|
| amoxicillin | Amoxil | Broad | Most prescribed antibiotic |
| amoxicillin/clavulanate | Augmentin | Broad + beta-lactamase | Clavulanate extends coverage |
| ampicillin | Principen | Broad | Available IV |
| penicillin V | Pen-Vee K | Narrow | Strep throat first-line |
Storage: Amoxicillin suspension - refrigerate after reconstitution; discard after 14 days
Allergy Alert: ~10% of patients report penicillin allergy; true IgE-mediated allergy is less common
Cephalosporins
| Generation | Examples | Generic | Brand | Coverage |
|---|---|---|---|---|
| 1st | cephalexin | cephalexin | Keflex | Gram-positive, some gram-negative |
| 2nd | cefuroxime | cefuroxime | Ceftin | Expanded gram-negative |
| 3rd | ceftriaxone | ceftriaxone | Rocephin | Broad, CNS penetration |
| 3rd | cefdinir | cefdinir | Omnicef | Oral, good coverage |
Cross-Reactivity: ~1-2% cross-reactivity with penicillin allergy (lower than previously thought)
Fluoroquinolones (-floxacin)
| Generic Name | Brand Name | Key Indications |
|---|---|---|
| ciprofloxacin | Cipro | UTI, respiratory, anthrax |
| levofloxacin | Levaquin | Respiratory, UTI |
| moxifloxacin | Avelox | Respiratory (no UTI coverage) |
Black Box Warnings:
- Tendon rupture (especially Achilles)
- Peripheral neuropathy
- CNS effects
- Avoid in children unless no alternative
Drug Interactions: Chelates with divalent cations (Ca, Mg, Fe, Al) - separate from antacids by 2-4 hours
Macrolides (-mycin/-thromycin)
| Generic Name | Brand Name | Key Points |
|---|---|---|
| azithromycin | Zithromax, Z-Pak | QT prolongation risk |
| clarithromycin | Biaxin | CYP3A4 inhibitor |
| erythromycin | E-Mycin, Ery-Tab | GI side effects common |
Common Use: Azithromycin 250 mg - "Z-Pak" is 6 tablets: 2 on day 1, then 1 daily for 4 days
Tetracyclines (-cycline)
| Generic Name | Brand Name | Key Points |
|---|---|---|
| doxycycline | Vibramycin, Doryx | Photosensitivity, take with food |
| minocycline | Minocin | Vertigo, discoloration |
| tetracycline | Sumycin | Take on empty stomach |
Warnings:
- Contraindicated in pregnancy (category D)
- Avoid in children under 8 (tooth discoloration)
- Photosensitivity - avoid sun exposure
- Take with full glass of water; remain upright 30 minutes
Antiviral Medications
| Generic Name | Brand Name | Indication | Key Points |
|---|---|---|---|
| acyclovir | Zovirax | Herpes, shingles | Dose adjust for renal function |
| valacyclovir | Valtrex | Herpes, shingles | Prodrug of acyclovir, better absorption |
| oseltamivir | Tamiflu | Influenza | Start within 48 hours of symptoms |
| tenofovir/emtricitabine | Truvada, Descovy | HIV prevention (PrEP) | Once daily |
Antifungal Medications
| Generic Name | Brand Name | Type | Key Points |
|---|---|---|---|
| fluconazole | Diflucan | Azole | First-line for Candida; CYP inhibitor |
| itraconazole | Sporanox | Azole | Take with food; drug interactions |
| terbinafine | Lamisil | Allylamine | Onychomycosis; hepatotoxicity risk |
| nystatin | Mycostatin | Polyene | Topical/oral only; not absorbed |
| clotrimazole | Lotrimin | Azole | OTC topical antifungal |
Analgesic Medications
Non-Opioid Analgesics
Acetaminophen (Tylenol)
| Parameter | Details |
|---|---|
| Maximum Daily Dose | 3-4 grams/day (lower in liver disease, elderly, or with alcohol use) |
| Mechanism | COX inhibition in CNS; no peripheral anti-inflammatory effect |
| Hepatotoxicity | Leading cause of acute liver failure; risk increases with alcohol |
| Antidote | N-acetylcysteine (NAC) |
Counseling: Check all medications for acetaminophen content (combination products like Vicodin, Percocet, NyQuil)
NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)
| Generic Name | Brand Name | Key Points |
|---|---|---|
| ibuprofen | Motrin, Advil | Most common OTC NSAID |
| naproxen | Aleve, Naprosyn | Longer duration (BID dosing) |
| meloxicam | Mobic | Once daily, COX-2 preferential |
| diclofenac | Voltaren | Available topical |
| celecoxib | Celebrex | COX-2 selective, less GI risk |
Black Box Warning: Increased risk of cardiovascular events (MI, stroke) and GI bleeding
Contraindications:
- Active GI bleeding or ulcer history
- Severe renal impairment
- Third trimester of pregnancy
- Post-CABG surgery
Opioid Analgesics (Schedule II Controlled Substances)
| Generic Name | Brand Name | Relative Potency | Key Points |
|---|---|---|---|
| hydrocodone/APAP | Vicodin, Norco | Moderate | Schedule II; max APAP dose |
| oxycodone | OxyContin, Roxicodone | High | Immediate and extended release |
| oxycodone/APAP | Percocet | High | Watch total APAP dose |
| morphine | MS Contin, Kadian | Reference standard | Gold standard for severe pain |
| hydromorphone | Dilaudid | Very high | 4-7x more potent than morphine |
| fentanyl | Duragesic patch | Highest | 100x more potent than morphine |
| codeine | Tylenol #3 | Low | Schedule III with acetaminophen |
| tramadol | Ultram | Low | Schedule IV; serotonin syndrome risk |
Opioid Side Effects:
- Constipation (tolerance does NOT develop)
- Respiratory depression
- Sedation
- Nausea/vomiting
- Pruritus (itching)
Naloxone (Narcan): Opioid antagonist for overdose reversal; available OTC in many states
Controlled Substance Schedules Review
| Schedule | Characteristics | Examples |
|---|---|---|
| C-II | High abuse potential, accepted medical use | Oxycodone, morphine, fentanyl, amphetamines |
| C-III | Moderate abuse potential | Codeine combinations, testosterone |
| C-IV | Low abuse potential | Benzodiazepines, tramadol, zolpidem |
| C-V | Lowest abuse potential | Pregabalin, some cough syrups |
C-II Requirements: No refills allowed (21 CFR 1306.12). Federal law sets no time limit for filling a Schedule II prescription, but the pharmacist must confirm it is still needed, and state law may set a limit
A patient presents a prescription for ciprofloxacin and asks about taking it with their calcium supplement. What should they be advised?
Take them together for better absorption
Separate the doses by at least 2 hours
Stop taking the calcium supplement entirely
Crush the ciprofloxacin and mix with the calcium
What is the maximum recommended daily dose of acetaminophen for a healthy adult?
1,000 mg
2,000 mg
3,000-4,000 mg
6,000 mg
Which of the following statements about opioid medications is TRUE?
Tolerance develops to constipation over time
Schedule II opioids may have up to 5 refills
Naloxone can reverse opioid overdose
Tramadol is a Schedule II controlled substance
Sections you finish are checked off in the contents.