Does Aldara (imiquimod) cause side effects?

Aldara (imiquimod) is a topical medication that activates the immune system and is used for treating (not curing) genital warts

Although the exact mechanism of action Aldara is not known, Aldara is presumed to work by activating immune cells and chemicals that affect the immune system. 

Common side effects of Aldara include

Serious side effects of Aldara include

No drug-drug interactions have been conducted and established with Aldara. 

There are no adequate studies done on Aldara to determine safe and effective use in pregnant women. 

It is unknown if Aldara enters breast milk. It is best to be cautious before using it in breastfeeding mothers.

What are the side effects of Aldara (imiquimod)?

Side effects of imiquimod are:

Aldara (imiquimod) side effects list for healthcare professionals

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Clinical Trials Experience

Actinic Keratosis

The data described below reflect exposure to Aldara Cream or vehicle in 436 subjects enrolled in two double-blind, vehicle-controlled studies. Subjects applied Aldara Cream or vehicle to a 25 cm2 contiguous treatment area on the face or scalp 2 times per week for 16 weeks.

Table 2: Selected Adverse Reactions Occurring in > 1% of Aldara-Treated Subjects and at a Greater Frequency than with Vehicle in the Combined Studies (Actinic Keratosis)

Preferred Term Aldara Cream (n=215) Vehicle (n=221)
Application Site Reaction 71 (33%) 32 (14%)
Upper Resp Tract Infection 33 (15%) 27 (12%)
Sinusitis 16 (7%) 14 (6%)
Headache 11 (5%) 7 (3%)
Carcinoma Squamous 8 (4%) 5 (2%)
Diarrhea 6 (3%) 2 (1%)
Eczema 4 (2%) 3 (1%)
Back Pain 3 (1%) 2 (1%)
Fatigue 3 (1%) 2 (1%)
Fibrillation Atrial 3 (1%) 2 (1%)
Infection Viral 3 (1%) 2 (1%)
Dizziness 3 (1%) 1 (<1%)
Vomiting 3 (1%) 1 (<1%)
Urinary Tract Infection 3 (1%) 1 (<1%)
Fever 3 (1%) 0 (0%)
Rigors 3 (1%) 0 (0%)
Alopecia 3 (1%) 0 (0%)

Table 3: Application Site Reactions Reported by > 1% of Aldara-Treated Subjects and at a Greater Frequency than with Vehicle in the Combined Studies (Actinic Keratosis)

Included Term Aldara Cream (n=215) Vehicle (n=221)
Itching 44 (20%) 17 (8%)
Burning 13 (6%) 4 (2%)
Bleeding 7 (3%) 1 (<1%)
Stinging 6 (3%) 2 (1%)
Pain 6 (3%) 2 (1%)
Induration 5 (2%) 3 (1%)
Tenderness 4 (2%) 3 (1%)
Irritation 4 (2%) 0 (0%)

Local skin reactions were collected independently of the adverse reaction "application site reaction" in an effort to provide a better picture of the specific types of local reactions that might be seen.

The most frequently reported local skin reactions were

  • erythema,
  • flaking/scaling/dryness, and
  • scabbing/crusting.

The prevalence and severity of local skin reactions that occurred during controlled studies are shown in the following table.

Table 4: Local Skin Reactions in the Treatment Area as Assessed by the Investigator (Actinic Keratosis)

  Aldara Cream (n=215) Vehicle (n=220)
All Grades* Severe All Grades* Severe
Erythema 209 (97%) 38 (18%) 206 (93%) 5 (2%)
Flaking/Scaling/Dryness 199 (93%) 16 (7%) 199 (91%) 7 (3%)
Scabbing/Crusting 169 (79%) 18 (8%) 92 (42%) 4 (2%)
Edema 106 (49%) 0 (0%) 22 (10%) 0 (0%)
Erosion/Ulceration 103 (48%) 5 (2%) 20 (9%) 0 (0%)
Weeping/Exudate 45 (22%) 0 (0%) 3 (1%) 0 (0%)
Vesicles 19 (9%) 0 (0%) 2 (1%) 0 (0%)
*Mild, Moderate, or Severe

The adverse reactions that most frequently resulted in clinical intervention (e.g., rest periods, withdrawal from study) were local skin and application site reactions.

  • Overall, in the clinical studies, 2% (5/215) of subjects discontinued for local skin/application site reactions.
  • Of the 215 subjects treated, 35 subjects (16%) on Aldara Cream and 3 of 220 subjects (1%) on vehicle cream had at least one rest period.
  • Of these Aldara Cream subjects, 32 (91%) resumed therapy after a rest period.
  • In the AK studies, 22 of 678 (3.2%) of Aldara-treated subjects developed treatment site infections that required a rest period off Aldara Cream and were treated with antibiotics (19 with oral and 3 with topical).
  • Of the 206 Aldara subjects with both baseline and 8-week post-treatment scarring assessments, 6 (2.9%) had a greater degree of scarring scores at 8-weeks post-treatment than at baseline.
Superficial Basal Cell Carcinoma

The data described below reflect exposure to Aldara Cream or vehicle in 364 subjects enrolled in two double-blind, vehicle-controlled studies. Subjects applied Aldara Cream or vehicle 5 times per week for 6 weeks. The incidence of adverse reactions reported by > 1% of subjects during the studies is summarized below.

Table 5: Selected Adverse Reactions Reported by > 1% of Aldara-Treated Subjects and at a Greater Frequency than with Vehicle in the Combined Studies (Superficial Basal Cell Carcinoma)

Preferred Term Aldara Cream (n=185)
N%
Vehicle (n=179)
N%
Application Site Reaction 52 (28%) 5 (3%)
Headache 14 (8%) 4 (2%)
Back Pain 7 (4%) 1 (<1%)
Upper Resp Tract Infection 6 (3%) 2 (1%)
Rhinitis 5 (3%) 1 (<1%)
Lymphadenopathy 5 (3%) 1 (<1%)
Fatigue 4 (2%) 2 (1%)
Sinusitis 4 (2%) 1 (<1%)
Dyspepsia 3 (2%) 2 (1%)
Coughing 3 (2%) 1 (<1%)
Fever 3 (2%) 0 (0%)
Dizziness 2 (1%) 1 (<1%)
Anxiety 2 (1%) 1 (<1%)
Pharyngitis 2 (1%) 1 (<1%)
Chest Pain 2 (1%) 0 (0%)
Nausea 2 (1%) 0 (0%)

The most frequently reported adverse reactions were local skin and application site reactions including

  • erythema,
  • edema,
  • induration,
  • erosion,
  • flaking/scaling,
  • scabbing/crusting,
  • itching and burning at the application site.

The incidence of application site reactions reported by > 1% of the subjects during the 6 week treatment period is summarized in Table 6.

Table 6: Application Site Reactions Reported by > 1% of Aldara-Treated Subjects and at a Greater Frequency than with Vehicle in the Combined Studies (Superficial Basal Cell Carcinoma)

Included Term Aldara Cream (n=185) Vehicle (n=179)
Itching 30 (16%) 1 (1%)
Burning 11 (6%) 2 (1%)
Pain 6 (3%) 0 (0%)
Bleeding 4 (2%) 0 (0%)
Erythema 3 (2%) 0 (0%)
Papule(s) 3 (2%) 0 (0%)
Tenderness 2 (1%) 0 (0%)
Infection 2 (1%) 0 (0%)

Local skin reactions were collected independently of the adverse reaction "application site reaction" in an effort to provide a better picture of the specific types of local reactions that might be seen. The prevalence and severity of local skin reactions that occurred during controlled studies are shown in the following table.

Table 7: Local Skin Reactions in the Treatment Area as Assessed by the Investigator (Superficial Basal Cell Carcinoma)

  Aldara Cream (n=184) Vehicle (n=178)
All Grades* Severe All Grades* Severe
Erythema 184 (100%) 57 (31%) 173 (97%) 4 (2%)
Flaking/Scaling 167 (91%) 7 (4%) 135 (76%) 0 (0%)
Induration 154 (84%) 11 (6%) 94 (53%) 0 (0%)
Scabbing/Crusting 152 (83%) 35 (19%) 61 (34%) 0 (0%)
Edema 143 (78%) 13 (7%) 64 (36%) 0 (0%)
Erosion 122 (66%) 23 (13%) 25 (14%) 0 (0%)
Ulceration 73 (40%) 11 (6%) 6 (3%) 0 (0%)
Vesicles 57 (31%) 3 (2%) 4 (2%) 0 (0%)
*Mild, Moderate, or Severe

The adverse reactions that most frequently resulted in clinical intervention (e.g., rest periods, withdrawal from study) were local skin and application site reactions; 10% (19/185) of subjects received rest periods. The average number of doses not received per subject due to rest periods was 7 doses with a range of 2 to 22 doses; 79% of subjects (15/19) resumed therapy after a rest period. Overall, in the clinical studies, 2% (4/185) of subjects discontinued for local skin/application site reactions.

In the sBCC studies, 17 of 1266 (1.3%) Aldara-treated subjects developed treatment site infections that required a rest period and treatment with antibiotics.

External Genital Warts

In controlled clinical trials for genital warts, the most frequently reported adverse reactions were local skin and application site reactions.

Some subjects also reported systemic reactions. Overall, 1.2% (4/327) of the subjects discontinued due to local skin/application site reactions. The incidence and severity of local skin reactions during controlled clinical trials are shown in Table 8.

Table 8: Local Skin Reactions in the Treatment Area as Assessed by the Investigator (External Genital Warts)

  Aldara Cream Vehicle
Females (n=114) Males (n=156) Females (n=99) Males (n=157)
All All All All
Grades* Severe Grades* Severe Grades* Severe Grades* Severe
Erythema 74 (65%) 4 (4%) 90 (58%) 6 (4%) 21 (21%) 0 (0%) 34 (22%) 0 (0%)
Erosion 35 (31%) 1 (1%) 47 (30%) 2 (1%) 8 (8%) 0 (0%) 10 (6%) 0 (0%)
Excoriation/ Flaking 21 (18%) 0 (0%) 40 (26%) 1 (1%) 8 (8%) 0 (0%) 12 (8%) 0 (0%)
Edema 20 (18%) 1 (1%) 19 (12%) 0 (0%) 5 (5%) 0 (0%) 1 (1%) 0 (0%)
Scabbing 4 (4%) 0 (0%) 20 (13%) 0 (0%) 0 (0%) 0 (0%) 4 (3%) 0 (0%)
Induration 6 (5%) 0 (0%) 11 (7%) 0 (0%) 2 (2%) 0 (0%) 3 (2%) 0 (0%)
Ulceration 9 (8%) 3 (3%) 7 (4%) 0 (0%) 1 (1%) 0 (0%) 1 (1%) 0 (0%)
Vesicles 3 (3%) 0 (0%) 3 (2%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) 0 (0%)
*Mild, Moderate, or Severe

Remote site skin reactions were also reported. The severe remote site skin reactions reported for females were

  • erythema (3%),
  • ulceration (2%), and
  • edema (1%).

For males, the skin reactions included

  • erosion (2%), and
  • erythema, edema, induration, and excoriation/flaking (each 1%).

Selected adverse reactions judged to be probably or possibly related to Aldara Cream are listed below.

Table 9: Selected Treatment Related Reactions (External Genital Warts)

  Females Males
Aldara Cream
(n=117)
Vehicle
(n=103)
Aldara Cream
(n=156)
Vehicle
(n=158)
Application Site Disorders:
Application Site Reactions
Wart Site:        
Itching 38 (32%) 21 (20%) 34 (22%) 16 (10%)
Burning 30 (26%) 12 (12%) 14 (9%) 8 (5%)
Pain 9 (8%) 2 (2%) 3 (2%) 1 (1%)
Soreness 3 (3%) 0 (0%) 0 (0%) 1 (1%)
Fungal Infection* 13 (11%) 3 (3%) 3 (2%) 1 (1%)
Systemic Reactions:
Headache 5 (4%) 3 (3%) 8 (5%) 3 (2%)
Influenza-like symptoms 4 (3%) 2 (2%) 2 (1%) 0 (0%)
Myalgia 1 (1%) 0 (0%) 2 (1%) 1 (1%)
*Incidences reported without regard to causality with Aldara Cream.

Adverse reactions judged to be possibly or probably related to Aldara Cream and reported by more than 1% of subjects included:

  • Application Site Disorders: burning, hypopigmentation, irritation, itching, pain, rash, sensitivity, soreness, stinging, tenderness
  • Remote Site Reactions: bleeding, burning, itching, pain, tenderness, tinea cruris.
  • Body as a Whole: fatigue, fever, influenza-like symptoms
  • Central and Peripheral Nervous System Disorders: headache
  • Gastro-Intestinal System Disorders diarrhea
  • Musculo-Skeletal System Disorders: myalgia
Dermal Safety Studies

Provocative repeat insult patch test studies involving induction and challenge phases produced no evidence that Aldara Cream causes photoallergenicity or contact sensitization in healthy skin; however, cumulative irritancy testing revealed the potential for Aldara Cream to cause irritation, and application site reactions were reported in the clinical studies.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of Aldara Cream. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

What drugs interact with Aldara (imiquimod)?

No Information Provided

Summary

Aldara (imiquimod) is a topical medication that activates the immune system and is used for treating (not curing) genital warts. Common side effects of Aldara include application site reactions, upper respiratory tract infections, sinus infection, headache, diarrhea, skin erosion, fluid retention (edema), itching, flaking, and redness. There are no adequate studies done on Aldara to determine safe and effective use in pregnant women. It is unknown if Aldara enters breast milk.

Treatment & Diagnosis

Medications & Supplements

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Medically Reviewed on 10/9/2020
References
FDA Prescribing Information

Professional side effects and drug interactions sections courtesy of the U.S. Food and Drug Administration.
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