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How To Get Comfortable With Prescription Oral Medications

Jimmy D. Bartlett, O.D., D.Sc., FAAOProfessor Emeritus, The University of Alabama

at Birmingham

American Optometric AssociationJune 24, 2015

Disclosure Statement Alcon

Allergan

Bausch & Lomb

Jobson Medical Publishing

Shire Pharmaceuticals

United States Pharmacopeia

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How To Get Comfortable

Know the disease state you’re treating

Know the applicable drug(s) – not all, just the few you will be using

Know your patient and ask the right questions

Don’t memorize dosages – look them up

Clinical experience is key

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Clinical Pearls

Select your patients carefully Treat according to your comfort level, or just a little

beyond As your experience grows, so will your confidence If possible or practical, spend some time in a

colleague’s office, a “referral center,” or other clinic where you can gain hands-on experience

Review your cases with a trusted colleague, partner, or faculty member

Remember that there are many “correct” ways to treat ocular disease

Importance of Patient History

Gives clues to drug contraindications!

Medical

Hepatic

Renal

GI

Allergies

Medications, including OTC

Drug Interactions Causing Decreased GI Absorption of

Tetracyclines

Avoid milk, dairy, and antacids

Formation of drug-drug complexes (Ca2+, Mg2+)

Tetracyclines ↔ milk, dairy, antacids

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ORAL ANTIVIRAL DRUGS

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Ophthalmic Management

No therapy may be required

Topical steroids for corneal edema and anterior uveitis

Oral analgesics Oral Antivirals

Acyclovir

Should be started within 72 hours of skin lesions, but can be as late as 1 week

800 mg 5 times daily for 7 days

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Acyclovir Formulations

200 mg capsule

400 mg tablet

800 mg tablet

200 mg/5 ml suspension

(banana flavor)

Benefits of Acyclovir Therapy

Dendriformkeratopathy

Stromal keratitis

Anterior uveitis

Acute and chronic pain

Few side effects

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Valacyclovir (Valtrex)

Prodrug of acyclovir

Available as 500 mg tablet

Dosage is 1000 mg tid x 7 days

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Famciclovir (Famvir)

Prodrug of penciclovir

Available as 125, 250, 500 mg tablet

Dosage is 500 mg tid x 7 days

Side Effect(s) of Antivirals

Nausea

Diarrhea

What to Ask Before Prescribing

“Are you allergic to antiviral medications such as acyclovir (“Zovirax”)?”

“Have you been treated before with this medicine and had to stop for any reason?”

“Are you pregnant or nursing?”– get in the habit of asking this question unless the patient is not a female of childbearing potential

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Don’t Forget These Procedures!

Slit lamp exam

Uveitis?

IOP

Dilated fundus exam

Retinitis?

Acyclovir in Active HSV Keratitis Oral acyclovir 400 mg 5

times daily for treatment of HSV epithelial keratitis

Does not prevent stromal disease

Does not benefit stromal keratitis in patients receiving topical antivirals and steroids

Acyclovir in Preventing Recurrent HSV Keratitis Effective preventive dose is 400

mg BID (or Valtrex 500 mg QD) Dendritric (epithelial) Even effective for disciform

(stromal) Because of expense, greatest

benefit is in suppression of vision-threatening stromal disease

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ORAL ANTIBACTERIAL DRUGS

Conditions Requiring Oral Antibacterial Drugs

Preseptal cellulitisInternal hordeolumMeibomian gland dysfunction*Chlamydial conjunctivitisOcular rosacea*Dacryocystitis

A Good Place To Start is Preseptal Cellulitis or Internal

Hordeolum

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Eyelid Anatomy

Etiology

Local infection of eyelid or adnexa

Eyelid or facial trauma

Upper respiratory tract infection

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Be Comfortable With The Diagnosis– Differentiate From Orbital Cellulitis Proptosis

Visual acuity

Pupils

Ocular motility

Pain and fever

Constitutional symptoms

Differentiation From Orbital Cellulitis

Clinical Finding Preseptal Cellulitis Orbital Cellulitis

Proptosis Absent Marked

Chemosis Rare Common

Vision Normal Often reduced

Pupils Normal May be APD

Motility Usually normal Restricted

Pain on motion Absent Present

IOP Normal May be elevated

Temperature Usually normal Elevated (>102)

General Treatment Strategy (Adult)

Largely empirical

Penicillinase-resistant penicillin or

First-generation cephalosporin

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Penicillins

Penicillins Resistant to Penicillinase (β Lactamase)

Methacillin

Oxacillin

Cloxacillin

Dicloxacillin

Nafcillin

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Penicillin-ß Lactamase Inhibitor Combination (Broad Spectrum)

Amoxicillin/Clavulanate (Augmentin)

Expensive! (875 mg x 20 = $145)

Generic is $32-$46

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Augmentin*

Formulation Amoxicillin Clavulanic Acid

Tablet 250, 500, 875 mg 125 mg

Chewable Tablet 200, 250, 400 mg 28.5-62.5 mg

Oral Suspension125, 200, 400 mg

per 5 ml

28.5-62.5 mg

per 5 ml*All formulations are pregnancy cat. B and probably safe during breastfeeding

Augmentin Formulations

What To Ask Before Prescribing

“Are you allergic to penicillin or cephalosporin drugs such as Keflex?”

True allergy signs and symptoms include:Hives ItchingRashAcute low blood pressureLaryngeal edema/difficult breathing

Upset stomach is not an allergic response “Are you pregnant or nursing?”

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Cephalosporins

First-Generation Cephalosporins

Name Formulation

Cephalexin (generic)

Keflex

250, 500 cap

250, 500 mg, 1 g tab

125, 250 mg/5ml

Cephradine (generic)

Velosef

250, 500 mg cap

125, 250 mg/5ml

Cefadroxil (generic)

Duricef

250, 500 mg cap

125, 250 mg/5ml

Second-Generation Cephalosporins

Name Formulation

Cefaclor (generic)

Ceclor, Ceclor CD

250, 500 mg cap

375, 500 mg tab

125, 250, 375 mg/5ml

Cefprozil (Cefzil)250, 500 mg tab

125, 250 mg/5ml

Cefuroxime (Ceftin)125, 250, 500 mg tab

125, 250 mg/5ml

Loracarbef (Lorabid) 200, 400 mg cap/100, 200 mg/5ml

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Ceftin Formulations

As You Go From 1st to 2nd to 3rd

You increase gram-negative coverage

You lose gram-positive coverage

You increase cost astronomically!

So use 1st generation cephalosporins for adults and children with presumed staph infection

Use 2nd generation for children with URIs

Allergic Reactions to β-Lactam Antibiotics Prevalence of penicillin allergy is only 2% Avoid penicillin in patients with history of

severe PCN allergyAcute low blood pressureExtensive hives, swelling, itchingLaryngeal edema

Patients with mild PCN reactions can usually be given a cephalosporin

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Macrolides

Azithromycin FormulationsFormulation Strength Cost

Tablet 250, 600 mg

Oral Suspension*100, 200 mg/5ml

2 g/60 ml (single dose)

Z-Pak 250 mg tablets (6) $26

Tri-Pak 500 mg tablets (3) $44

*Take at least 1 hr before or 2 hr after meals

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What To Ask Before Prescribing

“Are you allergic to “mycin” drugs?”

“Did you have to stop treatment with a “mycin” drug for any reason?”

“Are you pregnant?”

Avoid clarithromycin in pregnancy (category C)

Azithromycin and erythromycin are cat. B

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Antibiotic Combinations

Trimethoprim/Sulfamethoxazole

Trimethoprim/Sulfamethoxazole

Name Formulation

Trimethoprim/sulfamethoxazole

(generic)

80 mg trim/400 mg sulf

160/800 mg (double strength)

40/200 mg/5ml

Bactrim, Bactrim DS

Cotrim, Cotrim DS

Septra, Septra DS

Same as above

Bactrim is a Sulfonamide!

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Sulfonamide (“Sulfa”) Allergy

“Sulfur” is not a sulfonamide

“Sulfites” are not sulfonamides

“Sulfates” are not sulfonamides

ACNE ROSACEA AND MEIBOMIAN GLAND DYSFUNCTION (MGD)

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Acne Rosacea

Tetracyclines

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Here We Use Tetracyclines As Antiinflammatories, Not Antimicrobials

Inhibit lipase activity of normal lid flora

Inhibit matrix metalloproteinases (MMPs) and other inflammatory mediators

Anticollagenase properties

Antilipase Activity and Matrix Metalloproteinase (MMP-9) Inhibition

Typical ResponseTo Treatment

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Prescription for Doxycycline

Doxycycline 50 mg

# 60Sig.: Take one PO BID for ocular rosacea

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Side Effects of Tetracyclines

Nausea, diarrhea, pseudomembranous colitis

For nausea, administer with food

Tooth discoloration, bone deformity

Photosensitization

Esophagitis (do not take within 1 hr of bedtime)

Side Effects of Oral Antibacterials

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Side Effects of Antibacterials

Hypersensitivity reactions

GI irritant effects

Nausea, diarrhea

Pseudomembranous colitis

Vaginal candidiasis

Vaginal Candidiasis

Treat with oral fluconazole (Diflucan)

150 mg PO x 1(single oral dose)

1-2 yogurts/day

Antifungal creams

PRESCRIBING DURING PREGNANCY

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Drug Use During Pregnancy

FDA Category

Clinical Implication

Example

A No risk to fetus Levothyroxine, vitamin B6

BNo evidence of risk

Azithromycin, erythromycin, dicloxacillin, cephalexin

CRisk cannot be ruled out

Clarithromycin, ciprofloxacin, methylprednisolone dose pack

D Risk to fetus Tetracycline, doxycycline

X Definite risk! Misoprostol, isotretinoin

PRESCRIBING FOR CHILDREN

Pediatric Dosage Calculation*Clark’s Rule

Pediatric Dose = Adult Dose x

or

Adult Dose x

Weight (kg)70

Weight (lb)150

*5 ml = 1 tsp

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Pediatric Dosage CalculationBy Age

Age Percent of Adult Dose>12 100%

6-12 50%

2-6 25%

Pediatric Azithromycin Example For FDA-Approved Dosage

6 year-old female

Weighs 40 lb

Recent URI

Presents with red, swollen, painful RUL

Dosage is 10mg/kg x 1d, then 5mg/kg x 4d

Zithromax 200mg/5 ml

Sig.: One tsp PO on first day, then one-half tsp QD x 4 days for eye infection. Take 1 h ac or 2 h pc

Pediatric Azithromycin Example

06/24/15

Amanda Jane Doe 6

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Reread Your Prescription for Accuracy!