Patients taking Plaquenil (hydroxychloroquine, Sanofi-Aventis) on a long-term basis may leave you scratching your head when it comes to coding the patient encounters. Although coding for long-term medications is not a difficult process, it often involves communicating with other physicians or specialists to obtain accurate information. While this clinical example focuses on Plaquenil, the concept works for any long-term medication.

ICD-10 Classifications

The ICD-10 section that covers long-term drug therapy is Z79, with many subsections and specific diagnosis codes. 

Because Plaquenil does not have its own specific category, clinicians should use Z79.899—Other Long Term (Current) Drug Therapy. But getting the right code is just one step in the process of correctly documenting the encounter. 

ICD-10 Codes for Long-term Therapies

CodeLong-term (current) use of
V – Valid For Claim Submission
Z79.01
anticoagulants
Z79.02
antithrombotics/antiplatelets
Z79.1
NSAIDs
Z79.2
antibiotics
Z79.3
hormonal contraceptives 
Z79.4
insulin
Z79.51
inhaled steroids
Z79.52
systemic steroids
Z79.810 selective estrogen receptor modulators
Z79.811
aromatase inhibitors
Z79.818
other agents affecting estrogen receptors and estrogen levels
Z79.82
aspirin
Z79.83
bisphosphonates
Z79.84
oral hypoglycemic drugs
Z79.891
opiate analgesic
Z79.899
other drug therapy
H – Not Valid for Claim Submission
Z79
drug therapy
Z79.0
anticoagulants and antithrombotics/antiplatelets
Z79.5
steroids
Z79.8
other drug therapy
Z79.81
agents affecting estrogen receptors and estrogen levels
Z79.89
other drug therapy

Code the Condition

When coding for these individuals, it is important to understand the mechanism in place. The patient is taking a long-term medication for a specific systemic condition, such as rheumatoid arthritis (RA), so the first step is coding for that. This is where communication with other physicians is paramount. You and the patient’s other providers need to remain consistent with the ICD-10 code used to describe the condition for which the patient is being treated. Once you know the primary systemic condition, you can code the medication use and any adverse effects that require further attention.

Example: Plaquenil 

Here’s the coding for a patient taking Plaquenil for RA:

1. Report M06.08 for RA, other, or M06.9 for RA, unspecified (always report the systemic disease state first).

2. Report Z79.899 for Plaquenil use for RA.

3. Always report both. Link to both, and if the carrier does not pay on the Z code, link to the M code first (or only link to the M code).

4. If maculopathy is present, report the adverse effect of the hydroxychloroquine as well:

T37.2x5A: Adverse effect of anti-malarials and drugs acting on other blood protozoa, initial encounter.

T37.2x5D: Adverse effect of anti-malarials and drugs acting on other blood protozoa, subsequent encounter.

T37.2x5S: Adverse effect of anti-malarials and drugs acting on other blood protozoa, sequela.

Understanding what you are clinically evaluating in a patient taking long-term medications and following the basic ICD-10 rules will help you be quite successful in caring for these patients and adding a valuable care component to your practice. 

Send questions and comments to rocodingconnection@gmail.com.